VintageBigBlue.org

 

Re: ovision worm help-follow up


Feb 3 11:32 AM

 


----------------------------

#41488 Feb 3 11:32 AM

well the good news is that

eyeballing a correction for drift

the range of my PE has been reduced from +/-30 to less than +/-3 arc

seconds!

(before PEC)



the bad news is that the PE is very jagged

jumping 3 arcsec and back over the course of a second or 2

so my long focal length images are much worse now and very difficult

to guide

:(



whwastro.homestead.com/files/temp/ovision_PE_run.xls



i took great care installing the worm

following the directions provided.



i have two observations:

1. there's definitely more backlash now ~2mm

there was almost none in the system with the original worm

perhaps explaining the high PE range

2. the ovision worm assembly itself did not turn smoothly (arrived

like that).



my guess/hope is that there's a bearing problem with the worm assembly

that could be easily corrected



any suggestions would be appreciated

ovision has not responded to my email



thanks



-bill w



----------------------------

#41489 Feb 3 12:03 PM

wups used main pixel scale instead of guider

the PE range is closer to +/- 5 arcsec (still not bad)

with jumps of 5-7 arc-sec in a second ;(

updated spread sheet

--- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@...> wrote:

>

> well the good news is that

> eyeballing a correction for drift

> the range of my PE has been reduced from +/-30 to less than +/-3 arc

> seconds!

> (before PEC)

>

> the bad news is that the PE is very jagged

> jumping 3 arcsec and back over the course of a second or 2

> so my long focal length images are much worse now and very difficult

> to guide

> :(

>

> whwastro.homestead.com/files/temp/ovision_PE_run.xls

>

> i took great care installing the worm

> following the directions provided.

>

> i have two observations:

> 1. there's definitely more backlash now ~2mm

> there was almost none in the system with the original worm

> perhaps explaining the high PE range

> 2. the ovision worm assembly itself did not turn smoothly (arrived

> like that).

>

> my guess/hope is that there's a bearing problem with the worm assembly

> that could be easily corrected

>

> any suggestions would be appreciated

> ovision has not responded to my email

>

> thanks

>

> -bill w

>



----------------------------

#41493 Feb 3 9:32 PM

Check the Oldham coupler for its alignment. Adjust the worm so that

you have 1mm play at the end of the counter weight shaft with the

mount a room temp. Make sure the worm is square with both sides having

an equal spacing from the mount flange.

Floyd --- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@...> wrote:

>

> wups used main pixel scale instead of guider

> the PE range is closer to +/- 5 arcsec (still not bad)

> with jumps of 5-7 arc-sec in a second ;(

> updated spread sheet

>

> --- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> >

> > well the good news is that

> > eyeballing a correction for drift

> > the range of my PE has been reduced from +/-30 to less than +/-3 arc

> > seconds!

> > (before PEC)

> >

> > the bad news is that the PE is very jagged

> > jumping 3 arcsec and back over the course of a second or 2

> > so my long focal length images are much worse now and very difficult

> > to guide

> > :(

> >

> > whwastro.homestead.com/files/temp/ovision_PE_run.xls

> >

> > i took great care installing the worm

> > following the directions provided.

> >

> > i have two observations:

> > 1. there's definitely more backlash now ~2mm

> > there was almost none in the system with the original worm

> > perhaps explaining the high PE range

> > 2. the ovision worm assembly itself did not turn smoothly (arrived

> > like that).

> >

> > my guess/hope is that there's a bearing problem with the worm assembly

> > that could be easily corrected

> >

> > any suggestions would be appreciated

> > ovision has not responded to my email

> >

> > thanks

> >

> > -bill w

> >

>



----------------------------

#41494 Feb 4 12:10 AM

thanks for your reply floyd

the oldham coupler looked well aligned

and the block square on installation

but will check again and cut down on the play a bit



what are your thoughts on the worm not spinning smoothly?

it's hard to imaging smooth tracking with that



-bill

--- In Losmandy_users@yahoogroups.com, "Floyd Blue" fblue@...> wrote:

>

> Check the Oldham coupler for its alignment. Adjust the worm so that

> you have 1mm play at the end of the counter weight shaft with the

> mount a room temp. Make sure the worm is square with both sides having

> an equal spacing from the mount flange.

> Floyd

> --- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> >

> > wups used main pixel scale instead of guider

> > the PE range is closer to +/- 5 arcsec (still not bad)

> > with jumps of 5-7 arc-sec in a second ;(

> > updated spread sheet

> >

> > --- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > >

> > > well the good news is that

> > > eyeballing a correction for drift

> > > the range of my PE has been reduced from +/-30 to less than +/-3 arc

> > > seconds!

> > > (before PEC)

> > >

> > > the bad news is that the PE is very jagged

> > > jumping 3 arcsec and back over the course of a second or 2

> > > so my long focal length images are much worse now and very difficult

> > > to guide

> > > :(

> > >

> > > whwastro.homestead.com/files/temp/ovision_PE_run.xls

> > >

> > > i took great care installing the worm

> > > following the directions provided.

> > >

> > > i have two observations:

> > > 1. there's definitely more backlash now ~2mm

> > > there was almost none in the system with the original worm

> > > perhaps explaining the high PE range

> > > 2. the ovision worm assembly itself did not turn smoothly (arrived

> > > like that).

> > >

> > > my guess/hope is that there's a bearing problem with the worm

assembly

> > > that could be easily corrected

> > >

> > > any suggestions would be appreciated

> > > ovision has not responded to my email

> > >

> > > thanks

> > >

> > > -bill w

> > >

> >

>







----------------------------

#41498 Feb 4 6:46 AM

Hi, Bill -



Another very real possibility is the adjustment of the brass screw on

the west side of the worm block. You should adjust this using the

dowel rod technique to ensure it can turn smoothly and easily using

your fingers. (Another way to easily test how well the complete

system turns is to insert an allen wrench into one of the allen

screws on the Oldham coupler and use that as a lever, with the Gemini

turned off, of course.) First, tighten your RA clutch and loosen the

brass screw. Wiggle the counterweight shaft and look for lateral

movement of the worm itself within the block (too loose). Then

tighten until there is no more play, and possibly another eighth or

sixteenth turn. Then perform the dowel/allen wrench test.



The amount of play or tightness of the worm inside the wormblock is

completely independent of the worm block's spacing on the mount. So,

you will want to get the worm adjustment right first. Then work on

the spacing of the worm block against the mount flange. In other

words, the 1-2mm play at the end of the shaft can be the result of

either too loose meshing between the worm gear and worm, or, too much

lateral play of the Ovision worm within it's housing, or both, and

you need to work these two variables independently.



Regards,



Bill in Gold Canyon, AZ



--- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@...> wrote:

>

> thanks for your reply floyd

> the oldham coupler looked well aligned

> and the block square on installation

> but will check again and cut down on the play a bit

>

> what are your thoughts on the worm not spinning smoothly?

> it's hard to imaging smooth tracking with that

>

> -bill

>

> --- In Losmandy_users@yahoogroups.com, "Floyd Blue" fblue@> wrote:

> >

> > Check the Oldham coupler for its alignment. Adjust the worm so

that

> > you have 1mm play at the end of the counter weight shaft with the

> > mount a room temp. Make sure the worm is square with both sides

having

> > an equal spacing from the mount flange.

> > Floyd

> > --- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@>

wrote:

> > >

> > > wups used main pixel scale instead of guider

> > > the PE range is closer to +/- 5 arcsec (still not bad)

> > > with jumps of 5-7 arc-sec in a second ;(

> > > updated spread sheet

> > >

> > > --- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@>

wrote:

> > > >

> > > > well the good news is that

> > > > eyeballing a correction for drift

> > > > the range of my PE has been reduced from +/-30 to less than

+/-3 arc

> > > > seconds!

> > > > (before PEC)

> > > >

> > > > the bad news is that the PE is very jagged

> > > > jumping 3 arcsec and back over the course of a second or 2

> > > > so my long focal length images are much worse now and very

difficult

> > > > to guide

> > > > :(

> > > >

> > > > whwastro.homestead.com/files/temp/ovision_PE_run.xls

> > > >

> > > > i took great care installing the worm

> > > > following the directions provided.

> > > >

> > > > i have two observations:

> > > > 1. there's definitely more backlash now ~2mm

> > > > there was almost none in the system with the original worm

> > > > perhaps explaining the high PE range

> > > > 2. the ovision worm assembly itself did not turn smoothly

(arrived

> > > > like that).

> > > >

> > > > my guess/hope is that there's a bearing problem with the worm

> assembly

> > > > that could be easily corrected

> > > >

> > > > any suggestions would be appreciated

> > > > ovision has not responded to my email

> > > >

> > > > thanks

> > > >

> > > > -bill w

> > > >

> > >

> >

>



----------------------------

#41502 Feb 4 11:00 AM

Hi Bill,

I would think the preload is too tight. Mark the brass adjuster on the

end then loosen it slightly and check for no lateral play. Then see if

it turns smoothly.

Another person had this problem but sent it back for replacement

without trying to adjust it. I would bet that this is the problem, but

it could be something else.

My worm turned freely and smoothly when I tested it.

Floyd --- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@...> wrote:

>

> thanks for your reply floyd

> the oldham coupler looked well aligned

> and the block square on installation

> but will check again and cut down on the play a bit

>

> what are your thoughts on the worm not spinning smoothly?

> it's hard to imaging smooth tracking with that

>

> -bill

>

> --- In Losmandy_users@yahoogroups.com, "Floyd Blue" fblue@> wrote:

> >

> > Check the Oldham coupler for its alignment. Adjust the worm so that

> > you have 1mm play at the end of the counter weight shaft with the

> > mount a room temp. Make sure the worm is square with both sides having

> > an equal spacing from the mount flange.

> > Floyd

> > --- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > >

> > > wups used main pixel scale instead of guider

> > > the PE range is closer to +/- 5 arcsec (still not bad)

> > > with jumps of 5-7 arc-sec in a second ;(

> > > updated spread sheet

> > >

> > > --- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > >

> > > > well the good news is that

> > > > eyeballing a correction for drift

> > > > the range of my PE has been reduced from +/-30 to less than

+/-3 arc

> > > > seconds!

> > > > (before PEC)

> > > >

> > > > the bad news is that the PE is very jagged

> > > > jumping 3 arcsec and back over the course of a second or 2

> > > > so my long focal length images are much worse now and very

difficult

> > > > to guide

> > > > :(

> > > >

> > > > whwastro.homestead.com/files/temp/ovision_PE_run.xls

> > > >

> > > > i took great care installing the worm

> > > > following the directions provided.

> > > >

> > > > i have two observations:

> > > > 1. there's definitely more backlash now ~2mm

> > > > there was almost none in the system with the original worm

> > > > perhaps explaining the high PE range

> > > > 2. the ovision worm assembly itself did not turn smoothly (arrived

> > > > like that).

> > > >

> > > > my guess/hope is that there's a bearing problem with the worm

> assembly

> > > > that could be easily corrected

> > > >

> > > > any suggestions would be appreciated

> > > > ovision has not responded to my email

> > > >

> > > > thanks

> > > >

> > > > -bill w

> > > >

> > >

> >

>







----------------------------

#41527 Feb 5 11:55 AM

thanks for the replies

i was able to reach ovision by telephone this AM

(my emails didn't get thru)

they suggested loosening the brass screw at one end slightly as well



will let you know how it goes

of course it's raining now



-bill w

--- In Losmandy_users@yahoogroups.com, "Floyd Blue" fblue@...> wrote:

>

> Hi Bill,

> I would think the preload is too tight. Mark the brass adjuster on the

> end then loosen it slightly and check for no lateral play. Then see if

> it turns smoothly.

> Another person had this problem but sent it back for replacement

> without trying to adjust it. I would bet that this is the problem, but

> it could be something else.

> My worm turned freely and smoothly when I tested it.

> Floyd

> --- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> >

> > thanks for your reply floyd

> > the oldham coupler looked well aligned

> > and the block square on installation

> > but will check again and cut down on the play a bit

> >

> > what are your thoughts on the worm not spinning smoothly?

> > it's hard to imaging smooth tracking with that

> >

> > -bill

> >

> > --- In Losmandy_users@yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > >

> > > Check the Oldham coupler for its alignment. Adjust the worm so that

> > > you have 1mm play at the end of the counter weight shaft with the

> > > mount a room temp. Make sure the worm is square with both sides

having

> > > an equal spacing from the mount flange.

> > > Floyd

> > > --- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > >

> > > > wups used main pixel scale instead of guider

> > > > the PE range is closer to +/- 5 arcsec (still not bad)

> > > > with jumps of 5-7 arc-sec in a second ;(

> > > > updated spread sheet

> > > >

> > > > --- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@>

wrote:

> > > > >

> > > > > well the good news is that

> > > > > eyeballing a correction for drift

> > > > > the range of my PE has been reduced from +/-30 to less than

> +/-3 arc

> > > > > seconds!

> > > > > (before PEC)

> > > > >

> > > > > the bad news is that the PE is very jagged

> > > > > jumping 3 arcsec and back over the course of a second or 2

> > > > > so my long focal length images are much worse now and very

> difficult

> > > > > to guide

> > > > > :(

> > > > >

> > > > > whwastro.homestead.com/files/temp/ovision_PE_run.xls

> > > > >

> > > > > i took great care installing the worm

> > > > > following the directions provided.

> > > > >

> > > > > i have two observations:

> > > > > 1. there's definitely more backlash now ~2mm

> > > > > there was almost none in the system with the original worm

> > > > > perhaps explaining the high PE range

> > > > > 2. the ovision worm assembly itself did not turn smoothly

(arrived

> > > > > like that).

> > > > >

> > > > > my guess/hope is that there's a bearing problem with the worm

> > assembly

> > > > > that could be easily corrected

> > > > >

> > > > > any suggestions would be appreciated

> > > > > ovision has not responded to my email

> > > > >

> > > > > thanks

> > > > >

> > > > > -bill w

> > > > >

> > > >

> > >

> >

>



----------------------------

#42548 Apr 21, 2009

just thought i'd give some follow up on my ovision worm

the first worm seemed to have a problem with the bearings

there was a very rough feeling when i rotated the worm by hand

(when not installed)

attempts to change the brass adjuster did not improve it



i was sent a new worm with a new design from ovision

it turns smoothly

i installed it this weekend

and my PE is much improved by virtue of elimination of the 76 second error

which was very large.



i analyzed my PE runs with PEC pro

and found some interesting results:

stock worm

Peak PE+:..18.32 arcsecs

Peak PE-:..-18.36 arcsecs

RMS PE: ..7.48 arcsecs

Av. PE+:..6.35 arcsecs

Av. PE-:..-6.15 arcsecs

Max Delta+:.1.51 arcsecs

Max Delta-:.-1.40 arcsecs

Av. Noise:.0.13 arcsecs



ovision worm

Peak PE+:..8.49 arcsecs

Peak PE-:..-8.20 arcsecs

RMS PE: ..3.79 arcsecs

Av. PE+:..3.31 arcsecs

Av. PE-:..-3.06 arcsecs

Max Delta+:.0.27 arcsecs

Max Delta-:.-0.30 arcsecs

Av. Noise:.0.04 arcsecs



looking at the frequency spectra

for the old worm

the 76 second predicted (calculated) PE was 17.1

the primary worm PE was 8.8

there was also a 117 second error of 8.8

not sure what this last is

it's close to worm bearing ball spin which has a period of 109?



for the new worm

the 76 second error is non existent

the 117 second error is non existent

however, the primary worm PE is 9.2



so the good news is that my PE has been cut in half

and it has the same period as the worm

so it should be amenable to PEC, perhaps halving the PE



but shouldn't the primary PE of the worm

be lower with a high precision worm?



-bill w

astro.whwiii.net

--- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@...> wrote:

>

> thanks for the replies

> i was able to reach ovision by telephone this AM

> (my emails didn't get thru)

> they suggested loosening the brass screw at one end slightly as well

>

> will let you know how it goes

> of course it's raining now

>

> -bill w

>

> --- In Losmandy_users@yahoogroups.com, "Floyd Blue" fblue@> wrote:

> >

> > Hi Bill,

> > I would think the preload is too tight. Mark the brass adjuster on the

> > end then loosen it slightly and check for no lateral play. Then see if

> > it turns smoothly.

> > Another person had this problem but sent it back for replacement

> > without trying to adjust it. I would bet that this is the problem, but

> > it could be something else.

> > My worm turned freely and smoothly when I tested it.

> > Floyd

> > --- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > >

> > > thanks for your reply floyd

> > > the oldham coupler looked well aligned

> > > and the block square on installation

> > > but will check again and cut down on the play a bit

> > >

> > > what are your thoughts on the worm not spinning smoothly?

> > > it's hard to imaging smooth tracking with that

> > >

> > > -bill

> > >

> > > --- In Losmandy_users@yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > >

> > > > Check the Oldham coupler for its alignment. Adjust the worm so that

> > > > you have 1mm play at the end of the counter weight shaft with the

> > > > mount a room temp. Make sure the worm is square with both sides

> having

> > > > an equal spacing from the mount flange.

> > > > Floyd

> > > > --- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > >

> > > > > wups used main pixel scale instead of guider

> > > > > the PE range is closer to +/- 5 arcsec (still not bad)

> > > > > with jumps of 5-7 arc-sec in a second ;(

> > > > > updated spread sheet

> > > > >

> > > > > --- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@>

> wrote:

> > > > > >

> > > > > > well the good news is that

> > > > > > eyeballing a correction for drift

> > > > > > the range of my PE has been reduced from +/-30 to less than

> > +/-3 arc

> > > > > > seconds!

> > > > > > (before PEC)

> > > > > >

> > > > > > the bad news is that the PE is very jagged

> > > > > > jumping 3 arcsec and back over the course of a second or 2

> > > > > > so my long focal length images are much worse now and very

> > difficult

> > > > > > to guide

> > > > > > :(

> > > > > >

> > > > > > whwastro.homestead.com/files/temp/ovision_PE_run.xls

> > > > > >

> > > > > > i took great care installing the worm

> > > > > > following the directions provided.

> > > > > >

> > > > > > i have two observations:

> > > > > > 1. there's definitely more backlash now ~2mm

> > > > > > there was almost none in the system with the original worm

> > > > > > perhaps explaining the high PE range

> > > > > > 2. the ovision worm assembly itself did not turn smoothly

> (arrived

> > > > > > like that).

> > > > > >

> > > > > > my guess/hope is that there's a bearing problem with the worm

> > > assembly

> > > > > > that could be easily corrected

> > > > > >

> > > > > > any suggestions would be appreciated

> > > > > > ovision has not responded to my email

> > > > > >

> > > > > > thanks

> > > > > >

> > > > > > -bill w

> > > > > >

> > > > >

> > > >

> > >

> >

>







----------------------------

#42558 Apr 21, 2009

Bill,







Your original worm will have been run in from your use of the mount, these

aren't bad worms just a good worm in a bad block.



Your new worm will only get better as it is run in.



My mount with original block and worm gives these results







Peak PE+: 2.8 arcsecs

Peak PE-: -3.8 arcsecs

RMS PE: .877 arcsecs



Worm Period PE: 1.45

76 second PE was .55







Roy







-----Original Message-----

From: Losmandy_users@yahoogroups.com [mailto:Losmandy_users@yahoogroups.com]

On Behalf Of fndnmonyhoo

Sent: Tuesday, April 21, 2009 11:57 AM

To: Losmandy_users@yahoogroups.com

Subject: [Losmandy_users] Re: ovision worm help-follow up

















just thought i'd give some follow up on my ovision worm

the first worm seemed to have a problem with the bearings

there was a very rough feeling when i rotated the worm by hand

(when not installed)

attempts to change the brass adjuster did not improve it



i was sent a new worm with a new design from ovision

it turns smoothly

i installed it this weekend

and my PE is much improved by virtue of elimination of the 76 second error

which was very large.



i analyzed my PE runs with PEC pro

and found some interesting results:

stock worm

Peak PE+: 18.32 arcsecs

Peak PE-: -18.36 arcsecs

RMS PE: 7.48 arcsecs

Av. PE+: 6.35 arcsecs

Av. PE-: -6.15 arcsecs

Max Delta+: 1.51 arcsecs

Max Delta-: -1.40 arcsecs

Av. Noise: 0.13 arcsecs



ovision worm

Peak PE+: 8.49 arcsecs

Peak PE-: -8.20 arcsecs

RMS PE: 3.79 arcsecs

Av. PE+: 3.31 arcsecs

Av. PE-: -3.06 arcsecs

Max Delta+: 0.27 arcsecs

Max Delta-: -0.30 arcsecs

Av. Noise: 0.04 arcsecs



looking at the frequency spectra

for the old worm

the 76 second predicted (calculated) PE was 17.1

the primary worm PE was 8.8

there was also a 117 second error of 8.8

not sure what this last is

it's close to worm bearing ball spin which has a period of 109?



for the new worm

the 76 second error is non existent

the 117 second error is non existent

however, the primary worm PE is 9.2



so the good news is that my PE has been cut in half

and it has the same period as the worm

so it should be amenable to PEC, perhaps halving the PE



but shouldn't the primary PE of the worm

be lower with a high precision worm?



-bill w

astro.whwiii.net



--- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

yahoogroups.com, "fndnmonyhoo" mosg@...> wrote: >

> thanks for the replies

> i was able to reach ovision by telephone this AM

> (my emails didn't get thru)

> they suggested loosening the brass screw at one end slightly as well

>

> will let you know how it goes

> of course it's raining now

>

> -bill w

>

> --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

yahoogroups.com, "Floyd Blue" fblue@> wrote: > >

> > Hi Bill,

> > I would think the preload is too tight. Mark the brass adjuster on the

> > end then loosen it slightly and check for no lateral play. Then see if

> > it turns smoothly.

> > Another person had this problem but sent it back for replacement

> > without trying to adjust it. I would bet that this is the problem, but

> > it could be something else.

> > My worm turned freely and smoothly when I tested it.

> > Floyd

> > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

yahoogroups.com, "fndnmonyhoo" mosg@> wrote: > > >

> > > thanks for your reply floyd

> > > the oldham coupler looked well aligned

> > > and the block square on installation

> > > but will check again and cut down on the play a bit

> > >

> > > what are your thoughts on the worm not spinning smoothly?

> > > it's hard to imaging smooth tracking with that

> > >

> > > -bill

> > >

> > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

yahoogroups.com, "Floyd Blue" fblue@> wrote: > > > >

> > > > Check the Oldham coupler for its alignment. Adjust the worm so that

> > > > you have 1mm play at the end of the counter weight shaft with the

> > > > mount a room temp. Make sure the worm is square with both sides

> having

> > > > an equal spacing from the mount flange.

> > > > Floyd

> > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

yahoogroups.com, "fndnmonyhoo" mosg@> wrote: > > > > >

> > > > > wups used main pixel scale instead of guider

> > > > > the PE range is closer to +/- 5 arcsec (still not bad)

> > > > > with jumps of 5-7 arc-sec in a second ;(

> > > > > updated spread sheet

> > > > >

> > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

yahoogroups.com, "fndnmonyhoo" mosg@> > wrote:

> > > > > >

> > > > > > well the good news is that

> > > > > > eyeballing a correction for drift

> > > > > > the range of my PE has been reduced from +/-30 to less than

> > +/-3 arc

> > > > > > seconds!

> > > > > > (before PEC)

> > > > > >

> > > > > > the bad news is that the PE is very jagged

> > > > > > jumping 3 arcsec and back over the course of a second or 2

> > > > > > so my long focal length images are much worse now and very

> > difficult

> > > > > > to guide

> > > > > > :(

> > > > > >

> > > > > > whwastro.

whwastro.homestead.com/files/temp/ovision_PE_run.xls>

homestead.com/files/temp/ovision_PE_run.xls > > > > > >

> > > > > > i took great care installing the worm

> > > > > > following the directions provided.

> > > > > >

> > > > > > i have two observations:

> > > > > > 1. there's definitely more backlash now ~2mm

> > > > > > there was almost none in the system with the original worm

> > > > > > perhaps explaining the high PE range

> > > > > > 2. the ovision worm assembly itself did not turn smoothly

> (arrived

> > > > > > like that).

> > > > > >

> > > > > > my guess/hope is that there's a bearing problem with the worm

> > > assembly

> > > > > > that could be easily corrected

> > > > > >

> > > > > > any suggestions would be appreciated

> > > > > > ovision has not responded to my email

> > > > > >

> > > > > > thanks

> > > > > >

> > > > > > -bill w

> > > > > >

> > > > >

> > > >

> > >

> >

>











[Non-text portions of this message have been removed]







----------------------------

#42560 Apr 21, 2009

how on earth did you get values that low?!

--- In Losmandy_users@yahoogroups.com, "Roy Cummings" tr_cummings@...> wrote:

>

> Bill,

>

>

>

> Your original worm will have been run in from your use of the mount, these

> aren't bad worms just a good worm in a bad block.

>

> Your new worm will only get better as it is run in.

>

> My mount with original block and worm gives these results

>

>

>

> Peak PE+: 2.8 arcsecs

> Peak PE-: -3.8 arcsecs

> RMS PE: .877 arcsecs

>

> Worm Period PE: 1.45

> 76 second PE was .55

>

>

>

> Roy

>

>

>

> -----Original Message-----

> From: Losmandy_users@yahoogroups.com [mailto:Losmandy_users@yahoogroups.com]

> On Behalf Of fndnmonyhoo

> Sent: Tuesday, April 21, 2009 11:57 AM

> To: Losmandy_users@yahoogroups.com

> Subject: [Losmandy_users] Re: ovision worm help-follow up

>

>

>

>

>

>

>

>

> just thought i'd give some follow up on my ovision worm

> the first worm seemed to have a problem with the bearings

> there was a very rough feeling when i rotated the worm by hand

> (when not installed)

> attempts to change the brass adjuster did not improve it

>

> i was sent a new worm with a new design from ovision

> it turns smoothly

> i installed it this weekend

> and my PE is much improved by virtue of elimination of the 76 second error

> which was very large.

>

> i analyzed my PE runs with PEC pro

> and found some interesting results:

> stock worm

> Peak PE+: 18.32 arcsecs

> Peak PE-: -18.36 arcsecs

> RMS PE: 7.48 arcsecs

> Av. PE+: 6.35 arcsecs

> Av. PE-: -6.15 arcsecs

> Max Delta+: 1.51 arcsecs

> Max Delta-: -1.40 arcsecs

> Av. Noise: 0.13 arcsecs

>

> ovision worm

> Peak PE+: 8.49 arcsecs

> Peak PE-: -8.20 arcsecs

> RMS PE: 3.79 arcsecs

> Av. PE+: 3.31 arcsecs

> Av. PE-: -3.06 arcsecs

> Max Delta+: 0.27 arcsecs

> Max Delta-: -0.30 arcsecs

> Av. Noise: 0.04 arcsecs

>

> looking at the frequency spectra

> for the old worm

> the 76 second predicted (calculated) PE was 17.1

> the primary worm PE was 8.8

> there was also a 117 second error of 8.8

> not sure what this last is

> it's close to worm bearing ball spin which has a period of 109?

>

> for the new worm

> the 76 second error is non existent

> the 117 second error is non existent

> however, the primary worm PE is 9.2

>

> so the good news is that my PE has been cut in half

> and it has the same period as the worm

> so it should be amenable to PEC, perhaps halving the PE

>

> but shouldn't the primary PE of the worm

> be lower with a high precision worm?

>

> -bill w

> astro.whwiii.net

>

> --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> >

> > thanks for the replies

> > i was able to reach ovision by telephone this AM

> > (my emails didn't get thru)

> > they suggested loosening the brass screw at one end slightly as well

> >

> > will let you know how it goes

> > of course it's raining now

> >

> > -bill w

> >

> > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > >

> > > Hi Bill,

> > > I would think the preload is too tight. Mark the brass adjuster on the

> > > end then loosen it slightly and check for no lateral play. Then see if

> > > it turns smoothly.

> > > Another person had this problem but sent it back for replacement

> > > without trying to adjust it. I would bet that this is the problem, but

> > > it could be something else.

> > > My worm turned freely and smoothly when I tested it.

> > > Floyd

> > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > >

> > > > thanks for your reply floyd

> > > > the oldham coupler looked well aligned

> > > > and the block square on installation

> > > > but will check again and cut down on the play a bit

> > > >

> > > > what are your thoughts on the worm not spinning smoothly?

> > > > it's hard to imaging smooth tracking with that

> > > >

> > > > -bill

> > > >

> > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > > >

> > > > > Check the Oldham coupler for its alignment. Adjust the worm so that

> > > > > you have 1mm play at the end of the counter weight shaft with the

> > > > > mount a room temp. Make sure the worm is square with both sides

> > having

> > > > > an equal spacing from the mount flange.

> > > > > Floyd

> > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > > >

> > > > > > wups used main pixel scale instead of guider

> > > > > > the PE range is closer to +/- 5 arcsec (still not bad)

> > > > > > with jumps of 5-7 arc-sec in a second ;(

> > > > > > updated spread sheet

> > > > > >

> > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "fndnmonyhoo" mosg@>

> > wrote:

> > > > > > >

> > > > > > > well the good news is that

> > > > > > > eyeballing a correction for drift

> > > > > > > the range of my PE has been reduced from +/-30 to less than

> > > +/-3 arc

> > > > > > > seconds!

> > > > > > > (before PEC)

> > > > > > >

> > > > > > > the bad news is that the PE is very jagged

> > > > > > > jumping 3 arcsec and back over the course of a second or 2

> > > > > > > so my long focal length images are much worse now and very

> > > difficult

> > > > > > > to guide

> > > > > > > :(

> > > > > > >

> > > > > > > whwastro.

> whwastro.homestead.com/files/temp/ovision_PE_run.xls>

> homestead.com/files/temp/ovision_PE_run.xls

> > > > > > >

> > > > > > > i took great care installing the worm

> > > > > > > following the directions provided.

> > > > > > >

> > > > > > > i have two observations:

> > > > > > > 1. there's definitely more backlash now ~2mm

> > > > > > > there was almost none in the system with the original worm

> > > > > > > perhaps explaining the high PE range

> > > > > > > 2. the ovision worm assembly itself did not turn smoothly

> > (arrived

> > > > > > > like that).

> > > > > > >

> > > > > > > my guess/hope is that there's a bearing problem with the worm

> > > > assembly

> > > > > > > that could be easily corrected

> > > > > > >

> > > > > > > any suggestions would be appreciated

> > > > > > > ovision has not responded to my email

> > > > > > >

> > > > > > > thanks

> > > > > > >

> > > > > > > -bill w

> > > > > > >

> > > > > >

> > > > >

> > > >

> > >

> >

>

>

>

>

>

> [Non-text portions of this message have been removed]

>







----------------------------

#42561 Apr 21, 2009

Try this-stainless worm, gears lapped. The backlash in the gears is only about 2arc minutes. Havn't done the Pem pro thing but the PE measured from the film (the old way...) on this 60 min trail shows +-1.25 arc sec! (No PEC). this shot is prime focus with a C8 (2000mmfl).

-------------- Original message from "fndnmonyhoo" mosg@...>: --------------









how on earth did you get values that low?!

--- In Losmandy_users@yahoogroups.com, "Roy Cummings" tr_cummings@...> wrote:

>

> Bill,

>

>

>

> Your original worm will have been run in from your use of the mount, these

> aren't bad worms just a good worm in a bad block.

>

> Your new worm will only get better as it is run in.

>

> My mount with original block and worm gives these results

>

>

>

> Peak PE+: 2.8 arcsecs

> Peak PE-: -3.8 arcsecs

> RMS PE: .877 arcsecs

>

> Worm Period PE: 1.45

> 76 second PE was .55

>

>

>

> Roy

>

>

>

> -----Original Message-----

> From: Losmandy_users@yahoogroups.com [mailto:Losmandy_users@yahoogroups.com]

> On Behalf Of fndnmonyhoo

> Sent: Tuesday, April 21, 2009 11:57 AM

> To: Losmandy_users@yahoogroups.com

> Subject: [Losmandy_users] Re: ovision worm help-follow up

>

>

>

>

>

>

>

>

> just thought i'd give some follow up on my ovision worm

> the first worm seemed to have a problem with the bearings

> there was a very rough feeling when i rotated the worm by hand

> (when not installed)

> attempts to change the brass adjuster did not improve it

>

> i was sent a new worm with a new design from ovision

> it turns smoothly

> i installed it this weekend

> and my PE is much improved by virtue of elimination of the 76 second error

> which was very large.

>

> i analyzed my PE runs with PEC pro

> and found some interesting results:

> stock worm

> Peak PE+: 18.32 arcsecs

> Peak PE-: -18.36 arcsecs

> RMS PE: 7.48 arcsecs

> Av. PE+: 6.35 arcsecs

> Av. PE-: -6.15 arcsecs

> Max Delta+: 1.51 arcsecs

> Max Delta-: -1.40 arcsecs

> Av. Noise: 0.13 arcsecs

>

> ovision worm

> Peak PE+: 8.49 arcsecs

> Peak PE-: -8.20 arcsecs

> RMS PE: 3.79 arcsecs

> Av. PE+: 3.31 arcsecs

> Av. PE-: -3.06 arcsecs

> Max Delta+: 0.27 arcsecs

> Max Delta-: -0.30 arcsecs

> Av. Noise: 0.04 arcsecs

>

> looking at the frequency spectra

> for the old worm

> the 76 second predicted (calculated) PE was 17.1

> the primary worm PE was 8.8

> there was also a 117 second error of 8.8

> not sure what this last is

> it's close to worm bearing ball spin which has a period of 109?

>

> for the new worm

> the 76 second error is non existent

> the 117 second error is non existent

> however, the primary worm PE is 9.2

>

> so the good news is that my PE has been cut in half

> and it has the same period as the worm

> so it should be amenable to PEC, perhaps halving the PE

>

> but shouldn't the primary PE of the worm

> be lower with a high precision worm?

>

> -bill w

> astro.whwiii.net

>

> --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> >

> > thanks for the replies

> > i was able to reach ovision by telephone this AM

> > (my emails didn't get thru)

> > they suggested loosening the brass screw at one end slightly as well

> >

> > will let you know how it goes

> > of course it's raining now

> >

> > -bill w

> >

> > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > >

> > > Hi Bill,

> > > I would think the preload is too tight. Mark the brass adjuster on the

> > > end then loosen it slightly and check for no lateral play. Then see if

> > > it turns smoothly.

> > > Another person had this problem but sent it back for replacement

> > > without trying to adjust it. I would bet that this is the problem, but

> > > it could be something else.

> > > My worm turned freely and smoothly when I tested it.

> > > Floyd

> > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > >

> > > > thanks for your reply floyd

> > > > the oldham coupler looked well aligned

> > > > and the block square on installation

> > > > but will check again and cut down on the play a bit

> > > >

> > > > what are your thoughts on the worm not spinning smoothly?

> > > > it's hard to imaging smooth tracking with that

> > > >

> > > > -bill

> > > >

> > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > > >

> > > > > Check the Oldham coupler for its alignment. Adjust the worm so that

> > > > > you have 1mm play at the end of the counter weight shaft with the

> > > > > mount a room temp. Make sure the worm is square with both sides

> > having

> > > > > an equal spacing from the mount flange.

> > > > > Floyd

> > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > > >

> > > > > > wups used main pixel scale instead of guider

> > > > > > the PE range is closer to +/- 5 arcsec (still not bad)

> > > > > > with jumps of 5-7 arc-sec in a second ;(

> > > > > > updated spread sheet

> > > > > >

> > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "fndnmonyhoo" mosg@>

> > wrote:

> > > > > > >

> > > > > > > well the good news is that

> > > > > > > eyeballing a correction for drift

> > > > > > > the range of my PE has been reduced from +/-30 to less than

> > > +/-3 arc

> > > > > > > seconds!

> > > > > > > (before PEC)

> > > > > > >

> > > > > > > the bad news is that the PE is very jagged

> > > > > > > jumping 3 arcsec and back over the course of a second or 2

> > > > > > > so my long focal length images are much worse now and very

> > > difficult

> > > > > > > to guide

> > > > > > > :(

> > > > > > >

> > > > > > > whwastro.

> whwastro.homestead.com/files/temp/ovision_PE_run.xls>

> homestead.com/files/temp/ovision_PE_run.xls

> > > > > > >

> > > > > > > i took great care installing the worm

> > > > > > > following the directions provided.

> > > > > > >

> > > > > > > i have two observations:

> > > > > > > 1. there's definitely more backlash now ~2mm

> > > > > > > there was almost none in the system with the original worm

> > > > > > > perhaps explaining the high PE range

> > > > > > > 2. the ovision worm assembly itself did not turn smoothly

> > (arrived

> > > > > > > like that).

> > > > > > >

> > > > > > > my guess/hope is that there's a bearing problem with the worm

> > > > assembly

> > > > > > > that could be easily corrected

> > > > > > >

> > > > > > > any suggestions would be appreciated

> > > > > > > ovision has not responded to my email

> > > > > > >

> > > > > > > thanks

> > > > > > >

> > > > > > > -bill w

> > > > > > >

> > > > > >

> > > > >

> > > >

> > >

> >

>

>

>

>

>

> [Non-text portions of this message have been removed]

>











[Non-text portions of this message have been removed]







----------------------------

#42565 Apr 22, 2009

FYI, I routinely get good values like this with my Ovision worm as well. I actively guide so the guiding RMS is more important to me than PE, so I haven't measured the PE lately, but my guiding RMS is typically less than 1 arcsec, and sometimes it settles down to around 0.3 arcsec. That's important to me because I image at 2350 mm (C9.25 prime focus) and 0.8 arcsec/pixel.



My guider is a 400mm AT-66 so I'm dealing w/ fractions of a pixel in the guider. I usually get 0.2-0.3 pixels RMS guiding, and at 3.5 arcsec/pixel this is around 1 arcsec. When the guiding error drops down to 0.1 pixel (0.3 arcsec) or slightly lower, I'm having a good night.



And yes, this is all on a Losmandy G-11 sitting on a tripod. Fortunately I don't see much differential flexure, at least not in the 5 minute exposures I typically do.

-Joe



MaxIm DL

ST-402 main imager on C9.25

Atik-16ic as guider on AT-66

www.skyinsight.net/gallery/v/Ulowetz/

--- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@...> wrote:

>

> how on earth did you get values that low?!

>

> --- In Losmandy_users@yahoogroups.com, "Roy Cummings" tr_cummings@> wrote:

> >

> > Bill,

> >

> >

> >

> > Your original worm will have been run in from your use of the mount, these

> > aren't bad worms just a good worm in a bad block.

> >

> > Your new worm will only get better as it is run in.

> >

> > My mount with original block and worm gives these results

> >

> >

> >

> > Peak PE+: 2.8 arcsecs

> > Peak PE-: -3.8 arcsecs

> > RMS PE: .877 arcsecs

> >

> > Worm Period PE: 1.45

> > 76 second PE was .55

> >

> >

> >

> > Roy



----------------------------

#42572 Apr 22, 2009

Hi Bill,







Measured fixed worm block end distance to stop and adjusted right hand

(adjustable) block end to exact same. Used feeler gauges jammed in gap both

sides.



These measurements were only at 1.98 arc/pixel plate scale 770mm FL. In

looking over the run I see the star used was saturated, this may be why the

results are so low. Last year (maybe longer) with a C8 F6.3 .98 arc/pixel

plate scale and the mount was very (before worm block adjustment) new the

results were +5.8 /-7.8. I can send you the PEMPro data file if you like.

The mount guides without problems at my current FL with 20min exposures as

the norm. I just came up on the AP list for a MACH1 have to make a decision

in the next few days if I still want to go that route.







Roy







-----Original Message-----

From: Losmandy_users@yahoogroups.com [mailto:Losmandy_users@yahoogroups.com]

On Behalf Of fndnmonyhoo

Sent: Tuesday, April 21, 2009 9:02 PM

To: Losmandy_users@yahoogroups.com

Subject: [Losmandy_users] Re: ovision worm help-follow up

















how on earth did you get values that low?!



--- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

yahoogroups.com, "Roy Cummings" tr_cummings@...> wrote: >

> Bill,

>

>

>

> Your original worm will have been run in from your use of the mount, these

> aren't bad worms just a good worm in a bad block.

>

> Your new worm will only get better as it is run in.

>

> My mount with original block and worm gives these results

>

>

>

> Peak PE+: 2.8 arcsecs

> Peak PE-: -3.8 arcsecs

> RMS PE: .877 arcsecs

>

> Worm Period PE: 1.45

> 76 second PE was .55

>

>

>

> Roy

>

>

>

> -----Original Message-----

> From: Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

yahoogroups.com [mailto:Losmandy_users@

mailto:Losmandy_users%40yahoogroups.com> yahoogroups.com] > On Behalf Of fndnmonyhoo

> Sent: Tuesday, April 21, 2009 11:57 AM

> To: Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

yahoogroups.com > Subject: [Losmandy_users] Re: ovision worm help-follow up

>

>

>

>

>

>

>

>

> just thought i'd give some follow up on my ovision worm

> the first worm seemed to have a problem with the bearings

> there was a very rough feeling when i rotated the worm by hand

> (when not installed)

> attempts to change the brass adjuster did not improve it

>

> i was sent a new worm with a new design from ovision

> it turns smoothly

> i installed it this weekend

> and my PE is much improved by virtue of elimination of the 76 second error

> which was very large.

>

> i analyzed my PE runs with PEC pro

> and found some interesting results:

> stock worm

> Peak PE+: 18.32 arcsecs

> Peak PE-: -18.36 arcsecs

> RMS PE: 7.48 arcsecs

> Av. PE+: 6.35 arcsecs

> Av. PE-: -6.15 arcsecs

> Max Delta+: 1.51 arcsecs

> Max Delta-: -1.40 arcsecs

> Av. Noise: 0.13 arcsecs

>

> ovision worm

> Peak PE+: 8.49 arcsecs

> Peak PE-: -8.20 arcsecs

> RMS PE: 3.79 arcsecs

> Av. PE+: 3.31 arcsecs

> Av. PE-: -3.06 arcsecs

> Max Delta+: 0.27 arcsecs

> Max Delta-: -0.30 arcsecs

> Av. Noise: 0.04 arcsecs

>

> looking at the frequency spectra

> for the old worm

> the 76 second predicted (calculated) PE was 17.1

> the primary worm PE was 8.8

> there was also a 117 second error of 8.8

> not sure what this last is

> it's close to worm bearing ball spin which has a period of 109?

>

> for the new worm

> the 76 second error is non existent

> the 117 second error is non existent

> however, the primary worm PE is 9.2

>

> so the good news is that my PE has been cut in half

> and it has the same period as the worm

> so it should be amenable to PEC, perhaps halving the PE

>

> but shouldn't the primary PE of the worm

> be lower with a high precision worm?

>

> -bill w

> astro.whwiii.net

>

> --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> >

> > thanks for the replies

> > i was able to reach ovision by telephone this AM

> > (my emails didn't get thru)

> > they suggested loosening the brass screw at one end slightly as well

> >

> > will let you know how it goes

> > of course it's raining now

> >

> > -bill w

> >

> > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > >

> > > Hi Bill,

> > > I would think the preload is too tight. Mark the brass adjuster on the

> > > end then loosen it slightly and check for no lateral play. Then see if

> > > it turns smoothly.

> > > Another person had this problem but sent it back for replacement

> > > without trying to adjust it. I would bet that this is the problem, but

> > > it could be something else.

> > > My worm turned freely and smoothly when I tested it.

> > > Floyd

> > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > >

> > > > thanks for your reply floyd

> > > > the oldham coupler looked well aligned

> > > > and the block square on installation

> > > > but will check again and cut down on the play a bit

> > > >

> > > > what are your thoughts on the worm not spinning smoothly?

> > > > it's hard to imaging smooth tracking with that

> > > >

> > > > -bill

> > > >

> > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > > >

> > > > > Check the Oldham coupler for its alignment. Adjust the worm so

that > > > > > you have 1mm play at the end of the counter weight shaft with the

> > > > > mount a room temp. Make sure the worm is square with both sides

> > having

> > > > > an equal spacing from the mount flange.

> > > > > Floyd

> > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > > >

> > > > > > wups used main pixel scale instead of guider

> > > > > > the PE range is closer to +/- 5 arcsec (still not bad)

> > > > > > with jumps of 5-7 arc-sec in a second ;(

> > > > > > updated spread sheet

> > > > > >

> > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "fndnmonyhoo" mosg@>

> > wrote:

> > > > > > >

> > > > > > > well the good news is that

> > > > > > > eyeballing a correction for drift

> > > > > > > the range of my PE has been reduced from +/-30 to less than

> > > +/-3 arc

> > > > > > > seconds!

> > > > > > > (before PEC)

> > > > > > >

> > > > > > > the bad news is that the PE is very jagged

> > > > > > > jumping 3 arcsec and back over the course of a second or 2

> > > > > > > so my long focal length images are much worse now and very

> > > difficult

> > > > > > > to guide

> > > > > > > :(

> > > > > > >

> > > > > > > whwastro.

> whwastro.

whwastro.homestead.com/files/temp/ovision_PE_run.xls>

homestead.com/files/temp/ovision_PE_run.xls> > homestead.com/files/temp/ovision_PE_run.xls

> > > > > > >

> > > > > > > i took great care installing the worm

> > > > > > > following the directions provided.

> > > > > > >

> > > > > > > i have two observations:

> > > > > > > 1. there's definitely more backlash now ~2mm

> > > > > > > there was almost none in the system with the original worm

> > > > > > > perhaps explaining the high PE range

> > > > > > > 2. the ovision worm assembly itself did not turn smoothly

> > (arrived

> > > > > > > like that).

> > > > > > >

> > > > > > > my guess/hope is that there's a bearing problem with the worm

> > > > assembly

> > > > > > > that could be easily corrected

> > > > > > >

> > > > > > > any suggestions would be appreciated

> > > > > > > ovision has not responded to my email

> > > > > > >

> > > > > > > thanks

> > > > > > >

> > > > > > > -bill w

> > > > > > >

> > > > > >

> > > > >

> > > >

> > >

> >

>

>

>

>

>

> [Non-text portions of this message have been removed]

>











[Non-text portions of this message have been removed]







----------------------------

#42575 Apr 22, 2009

interesting,

i'll admit it, having no machining experience,

i've never heard of lapping

is this something that everyone knows about and does without difficulty

or do i risk messing up my new precision gear etc?



what was your PE before the lapping?



-bill w

--- In Losmandy_users@yahoogroups.com, drgenovese@... wrote:

>

> Try this-stainless worm, gears lapped. The backlash in the gears is only about 2arc minutes. Havn't done the Pem pro thing but the PE measured from the film (the old way...) on this 60 min trail shows +-1.25 arc sec! (No PEC). this shot is prime focus with a C8 (2000mmfl).

> -------------- Original message from "fndnmonyhoo" mosg@...>: --------------

>

>

>

>

> how on earth did you get values that low?!

>

> --- In Losmandy_users@yahoogroups.com, "Roy Cummings" tr_cummings@> wrote:

> >

> > Bill,

> >

> >

> >

> > Your original worm will have been run in from your use of the mount, these

> > aren't bad worms just a good worm in a bad block.

> >

> > Your new worm will only get better as it is run in.

> >

> > My mount with original block and worm gives these results

> >

> >

> >

> > Peak PE+: 2.8 arcsecs

> > Peak PE-: -3.8 arcsecs

> > RMS PE: .877 arcsecs

> >

> > Worm Period PE: 1.45

> > 76 second PE was .55

> >

> >

> >

> > Roy

> >

> >

> >

> > -----Original Message-----

> > From: Losmandy_users@yahoogroups.com [mailto:Losmandy_users@yahoogroups.com]

> > On Behalf Of fndnmonyhoo

> > Sent: Tuesday, April 21, 2009 11:57 AM

> > To: Losmandy_users@yahoogroups.com

> > Subject: [Losmandy_users] Re: ovision worm help-follow up

> >

> >

> >

> >

> >

> >

> >

> >

> > just thought i'd give some follow up on my ovision worm

> > the first worm seemed to have a problem with the bearings

> > there was a very rough feeling when i rotated the worm by hand

> > (when not installed)

> > attempts to change the brass adjuster did not improve it

> >

> > i was sent a new worm with a new design from ovision

> > it turns smoothly

> > i installed it this weekend

> > and my PE is much improved by virtue of elimination of the 76 second error

> > which was very large.

> >

> > i analyzed my PE runs with PEC pro

> > and found some interesting results:

> > stock worm

> > Peak PE+: 18.32 arcsecs

> > Peak PE-: -18.36 arcsecs

> > RMS PE: 7.48 arcsecs

> > Av. PE+: 6.35 arcsecs

> > Av. PE-: -6.15 arcsecs

> > Max Delta+: 1.51 arcsecs

> > Max Delta-: -1.40 arcsecs

> > Av. Noise: 0.13 arcsecs

> >

> > ovision worm

> > Peak PE+: 8.49 arcsecs

> > Peak PE-: -8.20 arcsecs

> > RMS PE: 3.79 arcsecs

> > Av. PE+: 3.31 arcsecs

> > Av. PE-: -3.06 arcsecs

> > Max Delta+: 0.27 arcsecs

> > Max Delta-: -0.30 arcsecs

> > Av. Noise: 0.04 arcsecs

> >

> > looking at the frequency spectra

> > for the old worm

> > the 76 second predicted (calculated) PE was 17.1

> > the primary worm PE was 8.8

> > there was also a 117 second error of 8.8

> > not sure what this last is

> > it's close to worm bearing ball spin which has a period of 109?

> >

> > for the new worm

> > the 76 second error is non existent

> > the 117 second error is non existent

> > however, the primary worm PE is 9.2

> >

> > so the good news is that my PE has been cut in half

> > and it has the same period as the worm

> > so it should be amenable to PEC, perhaps halving the PE

> >

> > but shouldn't the primary PE of the worm

> > be lower with a high precision worm?

> >

> > -bill w

> > astro.whwiii.net

> >

> > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > >

> > > thanks for the replies

> > > i was able to reach ovision by telephone this AM

> > > (my emails didn't get thru)

> > > they suggested loosening the brass screw at one end slightly as well

> > >

> > > will let you know how it goes

> > > of course it's raining now

> > >

> > > -bill w

> > >

> > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > >

> > > > Hi Bill,

> > > > I would think the preload is too tight. Mark the brass adjuster on the

> > > > end then loosen it slightly and check for no lateral play. Then see if

> > > > it turns smoothly.

> > > > Another person had this problem but sent it back for replacement

> > > > without trying to adjust it. I would bet that this is the problem, but

> > > > it could be something else.

> > > > My worm turned freely and smoothly when I tested it.

> > > > Floyd

> > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > >

> > > > > thanks for your reply floyd

> > > > > the oldham coupler looked well aligned

> > > > > and the block square on installation

> > > > > but will check again and cut down on the play a bit

> > > > >

> > > > > what are your thoughts on the worm not spinning smoothly?

> > > > > it's hard to imaging smooth tracking with that

> > > > >

> > > > > -bill

> > > > >

> > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > > > >

> > > > > > Check the Oldham coupler for its alignment. Adjust the worm so that

> > > > > > you have 1mm play at the end of the counter weight shaft with the

> > > > > > mount a room temp. Make sure the worm is square with both sides

> > > having

> > > > > > an equal spacing from the mount flange.

> > > > > > Floyd

> > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > > > >

> > > > > > > wups used main pixel scale instead of guider

> > > > > > > the PE range is closer to +/- 5 arcsec (still not bad)

> > > > > > > with jumps of 5-7 arc-sec in a second ;(

> > > > > > > updated spread sheet

> > > > > > >

> > > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "fndnmonyhoo" mosg@>

> > > wrote:

> > > > > > > >

> > > > > > > > well the good news is that

> > > > > > > > eyeballing a correction for drift

> > > > > > > > the range of my PE has been reduced from +/-30 to less than

> > > > +/-3 arc

> > > > > > > > seconds!

> > > > > > > > (before PEC)

> > > > > > > >

> > > > > > > > the bad news is that the PE is very jagged

> > > > > > > > jumping 3 arcsec and back over the course of a second or 2

> > > > > > > > so my long focal length images are much worse now and very

> > > > difficult

> > > > > > > > to guide

> > > > > > > > :(

> > > > > > > >

> > > > > > > > whwastro.

> > whwastro.homestead.com/files/temp/ovision_PE_run.xls>

> > homestead.com/files/temp/ovision_PE_run.xls

> > > > > > > >

> > > > > > > > i took great care installing the worm

> > > > > > > > following the directions provided.

> > > > > > > >

> > > > > > > > i have two observations:

> > > > > > > > 1. there's definitely more backlash now ~2mm

> > > > > > > > there was almost none in the system with the original worm

> > > > > > > > perhaps explaining the high PE range

> > > > > > > > 2. the ovision worm assembly itself did not turn smoothly

> > > (arrived

> > > > > > > > like that).

> > > > > > > >

> > > > > > > > my guess/hope is that there's a bearing problem with the worm

> > > > > assembly

> > > > > > > > that could be easily corrected

> > > > > > > >

> > > > > > > > any suggestions would be appreciated

> > > > > > > > ovision has not responded to my email

> > > > > > > >

> > > > > > > > thanks

> > > > > > > >

> > > > > > > > -bill w

> > > > > > > >

> > > > > > >

> > > > > >

> > > > >

> > > >

> > >

> >

> >

> >

> >

> >

> > [Non-text portions of this message have been removed]

> >

>

>

>

>

>

> [Non-text portions of this message have been removed]

>







----------------------------

#42580 Apr 22, 2009

Bill- first the bearing blocks have to be set square to avoid any side torque on the bearings which cause the dreaded "76 sec error". In my case the bearing blocks were square when placed flat against the mounting plate. If they arn't, simply slightly enlarge the bearing recess with a dremel so the bearing can move slightly and drill a tiny hole from the side. When squared off, a drop of red locktight wil keep it from wiggling further. To adjust the worm/worm wheel contact forget the spacers. Push the worm against the worm gear and lightly hand tighten the bolts to the bearing blocks keeping the worm tangent to the worm wheel (I scribed a reference line on the plate). To open the space up a little, just rotate the worm back and forth with you fingers until there is about 5 degrees of back and forth free rotation of the worm. Gently tighten the bolts and recheck this free rotation. If it opens up or tightens down readjust it- there is some feel to how tight the bolts should be to allow the bearing blocks to back off slightly but not slip when they are further tightened. Now - this will take a while- using your fingers turn the worm until the worm gear goes all the way around and mark the most play area of the worm gear to "map" it . Now readjust the worm/bearing blocks the same as above at the most play area of the worm gear (again with about 5 degrees of rotational play in rotating the worm.) (Of course it will be too tight everywhere else- it is instructive to hand turn the worm all the way around the worm gear again to see how rough the contact is in spots) ). Now apply 160 grit valve grinding coumpound ( from any car parts store) to the worm and worm gear and use a flexible shaft drill extension and chuck to attach a regular hand drill to the worm shaft. Now turn the worm at medium speed for 20 minutes or so- this will wear down the high spots on both gears(this is "lapping" ). To finish spend a while wiping all the oil and grit from all the teeth in both gears- you can't disassemble it because when you reassemble it the contact areas will shift slightly. Now try turning the worm by hand all the way around the worm gear again- the change is impressive! Regrease it ( I'm using white lithium grease but I don't think it matters). The result is the pictures on my DrG photo section. No I never got around to checking it before ( like I should have) But I am sure it is a hell of a lot lower now- +-1.25 arc sec. ( and that may be due to the Oldham coupler). One day I'll get around to doing a computer map with PhD guide....don't hold your breath though. This same technique should be used with the Ovision worms!-the roughness is in the worm gear! (By the way I have a Stainless worm)

-------------- Original message from "fndnmonyhoo" mosg@...>: --------------









interesting,

i'll admit it, having no machining experience,

i've never heard of lapping

is this something that everyone knows about and does without difficulty

or do i risk messing up my new precision gear etc?



what was your PE before the lapping?



-bill w

--- In Losmandy_users@yahoogroups.com, drgenovese@... wrote:

>

> Try this-stainless worm, gears lapped. The backlash in the gears is only about 2arc minutes. Havn't done the Pem pro thing but the PE measured from the film (the old way...) on this 60 min trail shows +-1.25 arc sec! (No PEC). this shot is prime focus with a C8 (2000mmfl).

> -------------- Original message from "fndnmonyhoo" mosg@...>: --------------

>

>

>

>

> how on earth did you get values that low?!

>

> --- In Losmandy_users@yahoogroups.com, "Roy Cummings" tr_cummings@> wrote:

> >

> > Bill,

> >

> >

> >

> > Your original worm will have been run in from your use of the mount, these

> > aren't bad worms just a good worm in a bad block.

> >

> > Your new worm will only get better as it is run in.

> >

> > My mount with original block and worm gives these results

> >

> >

> >

> > Peak PE+: 2.8 arcsecs

> > Peak PE-: -3.8 arcsecs

> > RMS PE: .877 arcsecs

> >

> > Worm Period PE: 1.45

> > 76 second PE was .55

> >

> >

> >

> > Roy

> >

> >

> >

> > -----Original Message-----

> > From: Losmandy_users@yahoogroups.com [mailto:Losmandy_users@yahoogroups.com]

> > On Behalf Of fndnmonyhoo

> > Sent: Tuesday, April 21, 2009 11:57 AM

> > To: Losmandy_users@yahoogroups.com

> > Subject: [Losmandy_users] Re: ovision worm help-follow up

> >

> >

> >

> >

> >

> >

> >

> >

> > just thought i'd give some follow up on my ovision worm

> > the first worm seemed to have a problem with the bearings

> > there was a very rough feeling when i rotated the worm by hand

> > (when not installed)

> > attempts to change the brass adjuster did not improve it

> >

> > i was sent a new worm with a new design from ovision

> > it turns smoothly

> > i installed it this weekend

> > and my PE is much improved by virtue of elimination of the 76 second error

> > which was very large.

> >

> > i analyzed my PE runs with PEC pro

> > and found some interesting results:

> > stock worm

> > Peak PE+: 18.32 arcsecs

> > Peak PE-: -18.36 arcsecs

> > RMS PE: 7.48 arcsecs

> > Av. PE+: 6.35 arcsecs

> > Av. PE-: -6.15 arcsecs

> > Max Delta+: 1.51 arcsecs

> > Max Delta-: -1.40 arcsecs

> > Av. Noise: 0.13 arcsecs

> >

> > ovision worm

> > Peak PE+: 8.49 arcsecs

> > Peak PE-: -8.20 arcsecs

> > RMS PE: 3.79 arcsecs

> > Av. PE+: 3.31 arcsecs

> > Av. PE-: -3.06 arcsecs

> > Max Delta+: 0.27 arcsecs

> > Max Delta-: -0.30 arcsecs

> > Av. Noise: 0.04 arcsecs

> >

> > looking at the frequency spectra

> > for the old worm

> > the 76 second predicted (calculated) PE was 17.1

> > the primary worm PE was 8.8

> > there was also a 117 second error of 8.8

> > not sure what this last is

> > it's close to worm bearing ball spin which has a period of 109?

> >

> > for the new worm

> > the 76 second error is non existent

> > the 117 second error is non existent

> > however, the primary worm PE is 9.2

> >

> > so the good news is that my PE has been cut in half

> > and it has the same period as the worm

> > so it should be amenable to PEC, perhaps halving the PE

> >

> > but shouldn't the primary PE of the worm

> > be lower with a high precision worm?

> >

> > -bill w

> > astro.whwiii.net

> >

> > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > >

> > > thanks for the replies

> > > i was able to reach ovision by telephone this AM

> > > (my emails didn't get thru)

> > > they suggested loosening the brass screw at one end slightly as well

> > >

> > > will let you know how it goes

> > > of course it's raining now

> > >

> > > -bill w

> > >

> > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > >

> > > > Hi Bill,

> > > > I would think the preload is too tight. Mark the brass adjuster on the

> > > > end then loosen it slightly and check for no lateral play. Then see if

> > > > it turns smoothly.

> > > > Another person had this problem but sent it back for replacement

> > > > without trying to adjust it. I would bet that this is the problem, but

> > > > it could be something else.

> > > > My worm turned freely and smoothly when I tested it.

> > > > Floyd

> > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > >

> > > > > thanks for your reply floyd

> > > > > the oldham coupler looked well aligned

> > > > > and the block square on installation

> > > > > but will check again and cut down on the play a bit

> > > > >

> > > > > what are your thoughts on the worm not spinning smoothly?

> > > > > it's hard to imaging smooth tracking with that

> > > > >

> > > > > -bill

> > > > >

> > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > > > >

> > > > > > Check the Oldham coupler for its alignment. Adjust the worm so that

> > > > > > you have 1mm play at the end of the counter weight shaft with the

> > > > > > mount a room temp. Make sure the worm is square with both sides

> > > having

> > > > > > an equal spacing from the mount flange.

> > > > > > Floyd

> > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > > > >

> > > > > > > wups used main pixel scale instead of guider

> > > > > > > the PE range is closer to +/- 5 arcsec (still not bad)

> > > > > > > with jumps of 5-7 arc-sec in a second ;(

> > > > > > > updated spread sheet

> > > > > > >

> > > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "fndnmonyhoo" mosg@>

> > > wrote:

> > > > > > > >

> > > > > > > > well the good news is that

> > > > > > > > eyeballing a correction for drift

> > > > > > > > the range of my PE has been reduced from +/-30 to less than

> > > > +/-3 arc

> > > > > > > > seconds!

> > > > > > > > (before PEC)

> > > > > > > >

> > > > > > > > the bad news is that the PE is very jagged

> > > > > > > > jumping 3 arcsec and back over the course of a second or 2

> > > > > > > > so my long focal length images are much worse now and very

> > > > difficult

> > > > > > > > to guide

> > > > > > > > :(

> > > > > > > >

> > > > > > > > whwastro.

> > whwastro.homestead.com/files/temp/ovision_PE_run.xls>

> > homestead.com/files/temp/ovision_PE_run.xls

> > > > > > > >

> > > > > > > > i took great care installing the worm

> > > > > > > > following the directions provided.

> > > > > > > >

> > > > > > > > i have two observations:

> > > > > > > > 1. there's definitely more backlash now ~2mm

> > > > > > > > there was almost none in the system with the original worm

> > > > > > > > perhaps explaining the high PE range

> > > > > > > > 2. the ovision worm assembly itself did not turn smoothly

> > > (arrived

> > > > > > > > like that).

> > > > > > > >

> > > > > > > > my guess/hope is that there's a bearing problem with the worm

> > > > > assembly

> > > > > > > > that could be easily corrected

> > > > > > > >

> > > > > > > > any suggestions would be appreciated

> > > > > > > > ovision has not responded to my email

> > > > > > > >

> > > > > > > > thanks

> > > > > > > >

> > > > > > > > -bill w

> > > > > > > >

> > > > > > >

> > > > > >

> > > > >

> > > >

> > >

> >

> >

> >

> >

> >

> > [Non-text portions of this message have been removed]

> >

>

>

>

>

>

> [Non-text portions of this message have been removed]

>









[Non-text portions of this message have been removed]







----------------------------

#42587 Apr 22, 2009

sheesh your PE out of the box was almost 1/3 of mine

i'm curious to see what the PEMPro data looks like

if you don't mind sending it



thanks

--- In Losmandy_users@yahoogroups.com, "Roy Cummings" tr_cummings@...> wrote:

>

> Hi Bill,

>

>

>

> Measured fixed worm block end distance to stop and adjusted right hand

> (adjustable) block end to exact same. Used feeler gauges jammed in gap both

> sides.

>

> These measurements were only at 1.98 arc/pixel plate scale 770mm FL. In

> looking over the run I see the star used was saturated, this may be why the

> results are so low. Last year (maybe longer) with a C8 F6.3 .98 arc/pixel

> plate scale and the mount was very (before worm block adjustment) new the

> results were +5.8 /-7.8. I can send you the PEMPro data file if you like.

> The mount guides without problems at my current FL with 20min exposures as

> the norm. I just came up on the AP list for a MACH1 have to make a decision

> in the next few days if I still want to go that route.

>

>

>

> Roy

>

>

>

> -----Original Message-----

> From: Losmandy_users@yahoogroups.com [mailto:Losmandy_users@yahoogroups.com]

> On Behalf Of fndnmonyhoo

> Sent: Tuesday, April 21, 2009 9:02 PM

> To: Losmandy_users@yahoogroups.com

> Subject: [Losmandy_users] Re: ovision worm help-follow up

>

>

>

>

>

>

>

>

> how on earth did you get values that low?!

>

> --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "Roy Cummings" tr_cummings@> wrote:

> >

> > Bill,

> >

> >

> >

> > Your original worm will have been run in from your use of the mount, these

> > aren't bad worms just a good worm in a bad block.

> >

> > Your new worm will only get better as it is run in.

> >

> > My mount with original block and worm gives these results

> >

> >

> >

> > Peak PE+: 2.8 arcsecs

> > Peak PE-: -3.8 arcsecs

> > RMS PE: .877 arcsecs

> >

> > Worm Period PE: 1.45

> > 76 second PE was .55

> >

> >

> >

> > Roy

> >

> >

> >

> > -----Original Message-----

> > From: Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com [mailto:Losmandy_users@

> mailto:Losmandy_users%40yahoogroups.com> yahoogroups.com]

> > On Behalf Of fndnmonyhoo

> > Sent: Tuesday, April 21, 2009 11:57 AM

> > To: Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com

> > Subject: [Losmandy_users] Re: ovision worm help-follow up

> >

> >

> >

> >

> >

> >

> >

> >

> > just thought i'd give some follow up on my ovision worm

> > the first worm seemed to have a problem with the bearings

> > there was a very rough feeling when i rotated the worm by hand

> > (when not installed)

> > attempts to change the brass adjuster did not improve it

> >

> > i was sent a new worm with a new design from ovision

> > it turns smoothly

> > i installed it this weekend

> > and my PE is much improved by virtue of elimination of the 76 second error

> > which was very large.

> >

> > i analyzed my PE runs with PEC pro

> > and found some interesting results:

> > stock worm

> > Peak PE+: 18.32 arcsecs

> > Peak PE-: -18.36 arcsecs

> > RMS PE: 7.48 arcsecs

> > Av. PE+: 6.35 arcsecs

> > Av. PE-: -6.15 arcsecs

> > Max Delta+: 1.51 arcsecs

> > Max Delta-: -1.40 arcsecs

> > Av. Noise: 0.13 arcsecs

> >

> > ovision worm

> > Peak PE+: 8.49 arcsecs

> > Peak PE-: -8.20 arcsecs

> > RMS PE: 3.79 arcsecs

> > Av. PE+: 3.31 arcsecs

> > Av. PE-: -3.06 arcsecs

> > Max Delta+: 0.27 arcsecs

> > Max Delta-: -0.30 arcsecs

> > Av. Noise: 0.04 arcsecs

> >

> > looking at the frequency spectra

> > for the old worm

> > the 76 second predicted (calculated) PE was 17.1

> > the primary worm PE was 8.8

> > there was also a 117 second error of 8.8

> > not sure what this last is

> > it's close to worm bearing ball spin which has a period of 109?

> >

> > for the new worm

> > the 76 second error is non existent

> > the 117 second error is non existent

> > however, the primary worm PE is 9.2

> >

> > so the good news is that my PE has been cut in half

> > and it has the same period as the worm

> > so it should be amenable to PEC, perhaps halving the PE

> >

> > but shouldn't the primary PE of the worm

> > be lower with a high precision worm?

> >

> > -bill w

> > astro.whwiii.net

> >

> > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > >

> > > thanks for the replies

> > > i was able to reach ovision by telephone this AM

> > > (my emails didn't get thru)

> > > they suggested loosening the brass screw at one end slightly as well

> > >

> > > will let you know how it goes

> > > of course it's raining now

> > >

> > > -bill w

> > >

> > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > >

> > > > Hi Bill,

> > > > I would think the preload is too tight. Mark the brass adjuster on the

> > > > end then loosen it slightly and check for no lateral play. Then see if

> > > > it turns smoothly.

> > > > Another person had this problem but sent it back for replacement

> > > > without trying to adjust it. I would bet that this is the problem, but

> > > > it could be something else.

> > > > My worm turned freely and smoothly when I tested it.

> > > > Floyd

> > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > >

> > > > > thanks for your reply floyd

> > > > > the oldham coupler looked well aligned

> > > > > and the block square on installation

> > > > > but will check again and cut down on the play a bit

> > > > >

> > > > > what are your thoughts on the worm not spinning smoothly?

> > > > > it's hard to imaging smooth tracking with that

> > > > >

> > > > > -bill

> > > > >

> > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > > > >

> > > > > > Check the Oldham coupler for its alignment. Adjust the worm so

> that

> > > > > > you have 1mm play at the end of the counter weight shaft with the

> > > > > > mount a room temp. Make sure the worm is square with both sides

> > > having

> > > > > > an equal spacing from the mount flange.

> > > > > > Floyd

> > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > > > >

> > > > > > > wups used main pixel scale instead of guider

> > > > > > > the PE range is closer to +/- 5 arcsec (still not bad)

> > > > > > > with jumps of 5-7 arc-sec in a second ;(

> > > > > > > updated spread sheet

> > > > > > >

> > > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "fndnmonyhoo" mosg@>

> > > wrote:

> > > > > > > >

> > > > > > > > well the good news is that

> > > > > > > > eyeballing a correction for drift

> > > > > > > > the range of my PE has been reduced from +/-30 to less than

> > > > +/-3 arc

> > > > > > > > seconds!

> > > > > > > > (before PEC)

> > > > > > > >

> > > > > > > > the bad news is that the PE is very jagged

> > > > > > > > jumping 3 arcsec and back over the course of a second or 2

> > > > > > > > so my long focal length images are much worse now and very

> > > > difficult

> > > > > > > > to guide

> > > > > > > > :(

> > > > > > > >

> > > > > > > > whwastro.

> > whwastro.

> whwastro.homestead.com/files/temp/ovision_PE_run.xls>

> homestead.com/files/temp/ovision_PE_run.xls>

> > homestead.com/files/temp/ovision_PE_run.xls

> > > > > > > >

> > > > > > > > i took great care installing the worm

> > > > > > > > following the directions provided.

> > > > > > > >

> > > > > > > > i have two observations:

> > > > > > > > 1. there's definitely more backlash now ~2mm

> > > > > > > > there was almost none in the system with the original worm

> > > > > > > > perhaps explaining the high PE range

> > > > > > > > 2. the ovision worm assembly itself did not turn smoothly

> > > (arrived

> > > > > > > > like that).

> > > > > > > >

> > > > > > > > my guess/hope is that there's a bearing problem with the worm

> > > > > assembly

> > > > > > > > that could be easily corrected

> > > > > > > >

> > > > > > > > any suggestions would be appreciated

> > > > > > > > ovision has not responded to my email

> > > > > > > >

> > > > > > > > thanks

> > > > > > > >

> > > > > > > > -bill w

> > > > > > > >

> > > > > > >

> > > > > >

> > > > >

> > > >

> > >

> >

> >

> >

> >

> >

> > [Non-text portions of this message have been removed]

> >

>

>

>

>

>

> [Non-text portions of this message have been removed]

>







----------------------------

#42588 Apr 22, 2009

Place the PEMPro txt file in this groups file section in a folder called

Cummings.







Roy











-----Original Message-----

From: Losmandy_users@yahoogroups.com [mailto:Losmandy_users@yahoogroups.com]

On Behalf Of fndnmonyhoo

Sent: Thursday, April 23, 2009 12:34 AM

To: Losmandy_users@yahoogroups.com

Subject: [Losmandy_users] Re: ovision worm help-follow up

















sheesh your PE out of the box was almost 1/3 of mine

i'm curious to see what the PEMPro data looks like

if you don't mind sending it



thanks



--- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

yahoogroups.com, "Roy Cummings" tr_cummings@...> wrote: >

> Hi Bill,

>

>

>

> Measured fixed worm block end distance to stop and adjusted right hand

> (adjustable) block end to exact same. Used feeler gauges jammed in gap

both > sides.

>

> These measurements were only at 1.98 arc/pixel plate scale 770mm FL. In

> looking over the run I see the star used was saturated, this may be why

the > results are so low. Last year (maybe longer) with a C8 F6.3 .98 arc/pixel

> plate scale and the mount was very (before worm block adjustment) new the

> results were +5.8 /-7.8. I can send you the PEMPro data file if you like.

> The mount guides without problems at my current FL with 20min exposures as

> the norm. I just came up on the AP list for a MACH1 have to make a

decision > in the next few days if I still want to go that route.

>

>

>

> Roy

>

>

>

> -----Original Message-----

> From: Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

yahoogroups.com [mailto:Losmandy_users@

mailto:Losmandy_users%40yahoogroups.com> yahoogroups.com] > On Behalf Of fndnmonyhoo

> Sent: Tuesday, April 21, 2009 9:02 PM

> To: Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

yahoogroups.com > Subject: [Losmandy_users] Re: ovision worm help-follow up

>

>

>

>

>

>

>

>

> how on earth did you get values that low?!

>

> --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "Roy Cummings" tr_cummings@> wrote:

> >

> > Bill,

> >

> >

> >

> > Your original worm will have been run in from your use of the mount,

these > > aren't bad worms just a good worm in a bad block.

> >

> > Your new worm will only get better as it is run in.

> >

> > My mount with original block and worm gives these results

> >

> >

> >

> > Peak PE+: 2.8 arcsecs

> > Peak PE-: -3.8 arcsecs

> > RMS PE: .877 arcsecs

> >

> > Worm Period PE: 1.45

> > 76 second PE was .55

> >

> >

> >

> > Roy

> >

> >

> >

> > -----Original Message-----

> > From: Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com [mailto:Losmandy_users@

> mailto:Losmandy_users%40yahoogroups.com> yahoogroups.com]

> > On Behalf Of fndnmonyhoo

> > Sent: Tuesday, April 21, 2009 11:57 AM

> > To: Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com

> > Subject: [Losmandy_users] Re: ovision worm help-follow up

> >

> >

> >

> >

> >

> >

> >

> >

> > just thought i'd give some follow up on my ovision worm

> > the first worm seemed to have a problem with the bearings

> > there was a very rough feeling when i rotated the worm by hand

> > (when not installed)

> > attempts to change the brass adjuster did not improve it

> >

> > i was sent a new worm with a new design from ovision

> > it turns smoothly

> > i installed it this weekend

> > and my PE is much improved by virtue of elimination of the 76 second

error > > which was very large.

> >

> > i analyzed my PE runs with PEC pro

> > and found some interesting results:

> > stock worm

> > Peak PE+: 18.32 arcsecs

> > Peak PE-: -18.36 arcsecs

> > RMS PE: 7.48 arcsecs

> > Av. PE+: 6.35 arcsecs

> > Av. PE-: -6.15 arcsecs

> > Max Delta+: 1.51 arcsecs

> > Max Delta-: -1.40 arcsecs

> > Av. Noise: 0.13 arcsecs

> >

> > ovision worm

> > Peak PE+: 8.49 arcsecs

> > Peak PE-: -8.20 arcsecs

> > RMS PE: 3.79 arcsecs

> > Av. PE+: 3.31 arcsecs

> > Av. PE-: -3.06 arcsecs

> > Max Delta+: 0.27 arcsecs

> > Max Delta-: -0.30 arcsecs

> > Av. Noise: 0.04 arcsecs

> >

> > looking at the frequency spectra

> > for the old worm

> > the 76 second predicted (calculated) PE was 17.1

> > the primary worm PE was 8.8

> > there was also a 117 second error of 8.8

> > not sure what this last is

> > it's close to worm bearing ball spin which has a period of 109?

> >

> > for the new worm

> > the 76 second error is non existent

> > the 117 second error is non existent

> > however, the primary worm PE is 9.2

> >

> > so the good news is that my PE has been cut in half

> > and it has the same period as the worm

> > so it should be amenable to PEC, perhaps halving the PE

> >

> > but shouldn't the primary PE of the worm

> > be lower with a high precision worm?

> >

> > -bill w

> > astro.whwiii.net

> >

> > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > >

> > > thanks for the replies

> > > i was able to reach ovision by telephone this AM

> > > (my emails didn't get thru)

> > > they suggested loosening the brass screw at one end slightly as well

> > >

> > > will let you know how it goes

> > > of course it's raining now

> > >

> > > -bill w

> > >

> > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > >

> > > > Hi Bill,

> > > > I would think the preload is too tight. Mark the brass adjuster on

the > > > > end then loosen it slightly and check for no lateral play. Then see

if > > > > it turns smoothly.

> > > > Another person had this problem but sent it back for replacement

> > > > without trying to adjust it. I would bet that this is the problem,

but > > > > it could be something else.

> > > > My worm turned freely and smoothly when I tested it.

> > > > Floyd

> > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > >

> > > > > thanks for your reply floyd

> > > > > the oldham coupler looked well aligned

> > > > > and the block square on installation

> > > > > but will check again and cut down on the play a bit

> > > > >

> > > > > what are your thoughts on the worm not spinning smoothly?

> > > > > it's hard to imaging smooth tracking with that

> > > > >

> > > > > -bill

> > > > >

> > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > > > >

> > > > > > Check the Oldham coupler for its alignment. Adjust the worm so

> that

> > > > > > you have 1mm play at the end of the counter weight shaft with

the > > > > > > mount a room temp. Make sure the worm is square with both sides

> > > having

> > > > > > an equal spacing from the mount flange.

> > > > > > Floyd

> > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > > > >

> > > > > > > wups used main pixel scale instead of guider

> > > > > > > the PE range is closer to +/- 5 arcsec (still not bad)

> > > > > > > with jumps of 5-7 arc-sec in a second ;(

> > > > > > > updated spread sheet

> > > > > > >

> > > > > > > --- In Losmandy_users@

mailto:Losmandy_users%40yahoogroups.com> > > yahoogroups.com, "fndnmonyhoo" mosg@>

> > > wrote:

> > > > > > > >

> > > > > > > > well the good news is that

> > > > > > > > eyeballing a correction for drift

> > > > > > > > the range of my PE has been reduced from +/-30 to less than

> > > > +/-3 arc

> > > > > > > > seconds!

> > > > > > > > (before PEC)

> > > > > > > >

> > > > > > > > the bad news is that the PE is very jagged

> > > > > > > > jumping 3 arcsec and back over the course of a second or 2

> > > > > > > > so my long focal length images are much worse now and very

> > > > difficult

> > > > > > > > to guide

> > > > > > > > :(

> > > > > > > >

> > > > > > > > whwastro.

> > whwastro.

> whwastro.

whwastro.homestead.com/files/temp/ovision_PE_run.xls>

homestead.com/files/temp/ovision_PE_run.xls> > homestead.com/files/temp/ovision_PE_run.xls>

> > homestead.com/files/temp/ovision_PE_run.xls

> > > > > > > >

> > > > > > > > i took great care installing the worm

> > > > > > > > following the directions provided.

> > > > > > > >

> > > > > > > > i have two observations:

> > > > > > > > 1. there's definitely more backlash now ~2mm

> > > > > > > > there was almost none in the system with the original worm

> > > > > > > > perhaps explaining the high PE range

> > > > > > > > 2. the ovision worm assembly itself did not turn smoothly

> > > (arrived

> > > > > > > > like that).

> > > > > > > >

> > > > > > > > my guess/hope is that there's a bearing problem with the

worm > > > > > assembly

> > > > > > > > that could be easily corrected

> > > > > > > >

> > > > > > > > any suggestions would be appreciated

> > > > > > > > ovision has not responded to my email

> > > > > > > >

> > > > > > > > thanks

> > > > > > > >

> > > > > > > > -bill w

> > > > > > > >

> > > > > > >

> > > > > >

> > > > >

> > > >

> > >

> >

> >

> >

> >

> >

> > [Non-text portions of this message have been removed]

> >

>

>

>

>

>

> [Non-text portions of this message have been removed]

>











[Non-text portions of this message have been removed]







----------------------------

#42596 Apr 23, 2009

thanks for the write up!



-bill w

--- In Losmandy_users@yahoogroups.com, drgenovese@... wrote:

>

> Bill- first the bearing blocks have to be set square to avoid any side torque on the bearings which cause the dreaded "76 sec error". In my case the bearing blocks were square when placed flat against the mounting plate. If they arn't, simply slightly enlarge the bearing recess with a dremel so the bearing can move slightly and drill a tiny hole from the side. When squared off, a drop of red locktight wil keep it from wiggling further. To adjust the worm/worm wheel contact forget the spacers. Push the worm against the worm gear and lightly hand tighten the bolts to the bearing blocks keeping the worm tangent to the worm wheel (I scribed a reference line on the plate). To open the space up a little, just rotate the worm back and forth with you fingers until there is about 5 degrees of back and forth free rotation of the worm. Gently tighten the bolts and recheck this free rotation. If it opens up or tightens down readjust it- there is some feel to how tight the bolts should be to allow the bearing blocks to back off slightly but not slip when they are further tightened. Now - this will take a while- using your fingers turn the worm until the worm gear goes all the way around and mark the most play area of the worm gear to "map" it . Now readjust the worm/bearing blocks the same as above at the most play area of the worm gear (again with about 5 degrees of rotational play in rotating the worm.) (Of course it will be too tight everywhere else- it is instructive to hand turn the worm all the way around the worm gear again to see how rough the contact is in spots) ). Now apply 160 grit valve grinding coumpound ( from any car parts store) to the worm and worm gear and use a flexible shaft drill extension and chuck to attach a regular hand drill to the worm shaft. Now turn the worm at medium speed for 20 minutes or so- this will wear down the high spots on both gears(this is "lapping" ). To finish spend a while wiping all the oil and grit from all the teeth in both gears- you can't disassemble it because when you reassemble it the contact areas will shift slightly. Now try turning the worm by hand all the way around the worm gear again- the change is impressive! Regrease it ( I'm using white lithium grease but I don't think it matters). The result is the pictures on my DrG photo section. No I never got around to checking it before ( like I should have) But I am sure it is a hell of a lot lower now- +-1.25 arc sec. ( and that may be due to the Oldham coupler). One day I'll get around to doing a computer map with PhD guide....don't hold your breath though. This same technique should be used with the Ovision worms!-the roughness is in the worm gear! (By the way I have a Stainless worm)

> -------------- Original message from "fndnmonyhoo" mosg@...>: --------------

>



----------------------------

#42600 Apr 24, 2009

Lapping is a way of getting your gears to "run-in" faster.

en.wikipedia.org/wiki/Lapping



In any machine, the surfaces, on a micron scale are rough. The highest peaks get worn off, but the process of running in can take many hours (in many cars you find the engine friction is of the order of 10-15% higher when the engine is new compared to what it is after 10,000 miles).



Once the surfaces are fully "run-in" the machine should be smoother than when it is new.

"Running-in" is however a natural process, and I personally would be somewhat reluctant to put an abrasive into the gears on my G11. You would also need to worry about the compatibility with the worm gear (this is usually bronze).



In other words, I don't believe it is necessary, provided you use your mount regularly, it should run-in naturally.



--- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@...> wrote:

>

> interesting,

> i'll admit it, having no machining experience,

> i've never heard of lapping

> is this something that everyone knows about and does without difficulty

> or do i risk messing up my new precision gear etc?

>

> what was your PE before the lapping?

>

> -bill w

>

> --- In Losmandy_users@yahoogroups.com, drgenovese@ wrote:

> >

> > Try this-stainless worm, gears lapped. The backlash in the gears is only about 2arc minutes. Havn't done the Pem pro thing but the PE measured from the film (the old way...) on this 60 min trail shows +-1.25 arc sec! (No PEC). this shot is prime focus with a C8 (2000mmfl).

> > -------------- Original message from "fndnmonyhoo" mosg@>: --------------

> >

> >

> >

> >

> > how on earth did you get values that low?!

> >

> > --- In Losmandy_users@yahoogroups.com, "Roy Cummings" tr_cummings@> wrote:

> > >

> > > Bill,

> > >

> > >

> > >

> > > Your original worm will have been run in from your use of the mount, these

> > > aren't bad worms just a good worm in a bad block.

> > >

> > > Your new worm will only get better as it is run in.

> > >

> > > My mount with original block and worm gives these results

> > >

> > >

> > >

> > > Peak PE+: 2.8 arcsecs

> > > Peak PE-: -3.8 arcsecs

> > > RMS PE: .877 arcsecs

> > >

> > > Worm Period PE: 1.45

> > > 76 second PE was .55

> > >

> > >

> > >

> > > Roy

> > >

> > >

> > >

> > > -----Original Message-----

> > > From: Losmandy_users@yahoogroups.com [mailto:Losmandy_users@yahoogroups.com]

> > > On Behalf Of fndnmonyhoo

> > > Sent: Tuesday, April 21, 2009 11:57 AM

> > > To: Losmandy_users@yahoogroups.com

> > > Subject: [Losmandy_users] Re: ovision worm help-follow up

> > >

> > >

> > >

> > >

> > >

> > >

> > >

> > >

> > > just thought i'd give some follow up on my ovision worm

> > > the first worm seemed to have a problem with the bearings

> > > there was a very rough feeling when i rotated the worm by hand

> > > (when not installed)

> > > attempts to change the brass adjuster did not improve it

> > >

> > > i was sent a new worm with a new design from ovision

> > > it turns smoothly

> > > i installed it this weekend

> > > and my PE is much improved by virtue of elimination of the 76 second error

> > > which was very large.

> > >

> > > i analyzed my PE runs with PEC pro

> > > and found some interesting results:

> > > stock worm

> > > Peak PE+: 18.32 arcsecs

> > > Peak PE-: -18.36 arcsecs

> > > RMS PE: 7.48 arcsecs

> > > Av. PE+: 6.35 arcsecs

> > > Av. PE-: -6.15 arcsecs

> > > Max Delta+: 1.51 arcsecs

> > > Max Delta-: -1.40 arcsecs

> > > Av. Noise: 0.13 arcsecs

> > >

> > > ovision worm

> > > Peak PE+: 8.49 arcsecs

> > > Peak PE-: -8.20 arcsecs

> > > RMS PE: 3.79 arcsecs

> > > Av. PE+: 3.31 arcsecs

> > > Av. PE-: -3.06 arcsecs

> > > Max Delta+: 0.27 arcsecs

> > > Max Delta-: -0.30 arcsecs

> > > Av. Noise: 0.04 arcsecs

> > >

> > > looking at the frequency spectra

> > > for the old worm

> > > the 76 second predicted (calculated) PE was 17.1

> > > the primary worm PE was 8.8

> > > there was also a 117 second error of 8.8

> > > not sure what this last is

> > > it's close to worm bearing ball spin which has a period of 109?

> > >

> > > for the new worm

> > > the 76 second error is non existent

> > > the 117 second error is non existent

> > > however, the primary worm PE is 9.2

> > >

> > > so the good news is that my PE has been cut in half

> > > and it has the same period as the worm

> > > so it should be amenable to PEC, perhaps halving the PE

> > >

> > > but shouldn't the primary PE of the worm

> > > be lower with a high precision worm?

> > >

> > > -bill w

> > > astro.whwiii.net

> > >

> > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > >

> > > > thanks for the replies

> > > > i was able to reach ovision by telephone this AM

> > > > (my emails didn't get thru)

> > > > they suggested loosening the brass screw at one end slightly as well

> > > >

> > > > will let you know how it goes

> > > > of course it's raining now

> > > >

> > > > -bill w

> > > >

> > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > > >

> > > > > Hi Bill,

> > > > > I would think the preload is too tight. Mark the brass adjuster on the

> > > > > end then loosen it slightly and check for no lateral play. Then see if

> > > > > it turns smoothly.

> > > > > Another person had this problem but sent it back for replacement

> > > > > without trying to adjust it. I would bet that this is the problem, but

> > > > > it could be something else.

> > > > > My worm turned freely and smoothly when I tested it.

> > > > > Floyd

> > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > > >

> > > > > > thanks for your reply floyd

> > > > > > the oldham coupler looked well aligned

> > > > > > and the block square on installation

> > > > > > but will check again and cut down on the play a bit

> > > > > >

> > > > > > what are your thoughts on the worm not spinning smoothly?

> > > > > > it's hard to imaging smooth tracking with that

> > > > > >

> > > > > > -bill

> > > > > >

> > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > > > > >

> > > > > > > Check the Oldham coupler for its alignment. Adjust the worm so that

> > > > > > > you have 1mm play at the end of the counter weight shaft with the

> > > > > > > mount a room temp. Make sure the worm is square with both sides

> > > > having

> > > > > > > an equal spacing from the mount flange.

> > > > > > > Floyd

> > > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > > > > >

> > > > > > > > wups used main pixel scale instead of guider

> > > > > > > > the PE range is closer to +/- 5 arcsec (still not bad)

> > > > > > > > with jumps of 5-7 arc-sec in a second ;(

> > > > > > > > updated spread sheet

> > > > > > > >

> > > > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com, "fndnmonyhoo" mosg@>

> > > > wrote:

> > > > > > > > >

> > > > > > > > > well the good news is that

> > > > > > > > > eyeballing a correction for drift

> > > > > > > > > the range of my PE has been reduced from +/-30 to less than

> > > > > +/-3 arc

> > > > > > > > > seconds!

> > > > > > > > > (before PEC)

> > > > > > > > >

> > > > > > > > > the bad news is that the PE is very jagged

> > > > > > > > > jumping 3 arcsec and back over the course of a second or 2

> > > > > > > > > so my long focal length images are much worse now and very

> > > > > difficult

> > > > > > > > > to guide

> > > > > > > > > :(

> > > > > > > > >

> > > > > > > > > whwastro.

> > > whwastro.homestead.com/files/temp/ovision_PE_run.xls>

> > > homestead.com/files/temp/ovision_PE_run.xls

> > > > > > > > >

> > > > > > > > > i took great care installing the worm

> > > > > > > > > following the directions provided.

> > > > > > > > >

> > > > > > > > > i have two observations:

> > > > > > > > > 1. there's definitely more backlash now ~2mm

> > > > > > > > > there was almost none in the system with the original worm

> > > > > > > > > perhaps explaining the high PE range

> > > > > > > > > 2. the ovision worm assembly itself did not turn smoothly

> > > > (arrived

> > > > > > > > > like that).

> > > > > > > > >

> > > > > > > > > my guess/hope is that there's a bearing problem with the worm

> > > > > > assembly

> > > > > > > > > that could be easily corrected

> > > > > > > > >

> > > > > > > > > any suggestions would be appreciated

> > > > > > > > > ovision has not responded to my email

> > > > > > > > >

> > > > > > > > > thanks

> > > > > > > > >

> > > > > > > > > -bill w

> > > > > > > > >

> > > > > > > >

> > > > > > >

> > > > > >

> > > > >

> > > >

> > >

> > >

> > >

> > >

> > >

> > > [Non-text portions of this message have been removed]

> > >

> >

> >

> >

> >

> >

> > [Non-text portions of this message have been removed]

> >

>







----------------------------

#42604 Apr 24, 2009

I disagree-auto motors are broken in after several thousand miles at several thousand RPM. At the speed of our motors it will take YEARS. Additionally it requires some pressure, and the motors do not have enough torque to turn through tight ares and they will stall and possibly burn out. My backlash is only about 11/2 arc minutes and if you try adjusting the gears this close without a run in you will burn out the motors.

-------------- Original message from "Ian Taylor" iantaylor2uk@...>: --------------









Lapping is a way of getting your gears to "run-in" faster.

en.wikipedia.org/wiki/Lapping



In any machine, the surfaces, on a micron scale are rough. The highest peaks get worn off, but the process of running in can take many hours (in many cars you find the engine friction is of the order of 10-15% higher when the engine is new compared to what it is after 10,000 miles).



Once the surfaces are fully "run-in" the machine should be smoother than when it is new.

"Running-in" is however a natural process, and I personally would be somewhat reluctant to put an abrasive into the gears on my G11. You would also need to worry about the compatibility with the worm gear (this is usually bronze).



In other words, I don't believe it is necessary, provided you use your mount regularly, it should run-in naturally.

--- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@...> wrote:

>

> interesting,

> i'll admit it, having no machining experience,

> i've never heard of lapping

> is this something that everyone knows about and does without difficulty

> or do i risk messing up my new precision gear etc?

>

> what was your PE before the lapping?

>

> -bill w

>

> --- In Losmandy_users@yahoogroups.com, drgenovese@ wrote:

> >

> > Try this-stainless worm, gears lapped. The backlash in the gears is only about 2arc minutes. Havn't done the Pem pro thing but the PE measured from the film (the old way...) on this 60 min trail shows +-1.25 arc sec! (No PEC). this shot is prime focus with a C8 (2000mmfl).

> > -------------- Original message from "fndnmonyhoo" mosg@>: --------------

> >

> >

> >

> >

> > how on earth did you get values that low?!

> >

> > --- In Losmandy_users@yahoogroups.com, "Roy Cummings" tr_cummings@> wrote:

> > >

> > > Bill,

> > >

> > >

> > >

> > > Your original worm will have been run in from your use of the mount, these

> > > aren't bad worms just a good worm in a bad block.

> > >

> > > Your new worm will only get better as it is run in.

> > >

> > > My mount with original block and worm gives these results

> > >

> > >

> > >

> > > Peak PE+: 2.8 arcsecs

> > > Peak PE-: -3.8 arcsecs

> > > RMS PE: .877 arcsecs

> > >

> > > Worm Period PE: 1.45

> > > 76 second PE was .55

> > >

> > >

> > >

> > > Roy

> > >

> > >

> > >

> > > -----Original Message-----

> > > From: Losmandy_users@yahoogroups.com [mailto:Losmandy_users@yahoogroups.com]

> > > On Behalf Of fndnmonyhoo

> > > Sent: Tuesday, April 21, 2009 11:57 AM

> > > To: Losmandy_users@yahoogroups.com

> > > Subject: [Losmandy_users] Re: ovision worm help-follow up

> > >

> > >

> > >

> > >

> > >

> > >

> > >

> > >

> > > just thought i'd give some follow up on my ovision worm

> > > the first worm seemed to have a problem with the bearings

> > > there was a very rough feeling when i rotated the worm by hand

> > > (when not installed)

> > > attempts to change the brass adjuster did not improve it

> > >

> > > i was sent a new worm with a new design from ovision

> > > it turns smoothly

> > > i installed it this weekend

> > > and my PE is much improved by virtue of elimination of the 76 second error

> > > which was very large.

> > >

> > > i analyzed my PE runs with PEC pro

> > > and found some interesting results:

> > > stock worm

> > > Peak PE+: 18.32 arcsecs

> > > Peak PE-: -18.36 arcsecs

> > > RMS PE: 7.48 arcsecs

> > > Av. PE+: 6.35 arcsecs

> > > Av. PE-: -6.15 arcsecs

> > > Max Delta+: 1.51 arcsecs

> > > Max Delta-: -1.40 arcsecs

> > > Av. Noise: 0.13 arcsecs

> > >

> > > ovision worm

> > > Peak PE+: 8.49 arcsecs

> > > Peak PE-: -8.20 arcsecs

> > > RMS PE: 3.79 arcsecs

> > > Av. PE+: 3.31 arcsecs

> > > Av. PE-: -3.06 arcsecs

> > > Max Delta+: 0.27 arcsecs

> > > Max Delta-: -0.30 arcsecs

> > > Av. Noise: 0.04 arcsecs

> > >

> > > looking at the frequency spectra

> > > for the old worm

> > > the 76 second predicted (calculated) PE was 17.1

> > > the primary worm PE was 8.8

> > > there was also a 117 second error of 8.8

> > > not sure what this last is

> > > it's close to worm bearing ball spin which has a period of 109?

> > >

> > > for the new worm

> > > the 76 second error is non existent

> > > the 117 second error is non existent

> > > however, the primary worm PE is 9.2

> > >

> > > so the good news is that my PE has been cut in half

> > > and it has the same period as the worm

> > > so it should be amenable to PEC, perhaps halving the PE

> > >

> > > but shouldn't the primary PE of the worm

> > > be lower with a high precision worm?

> > >

> > > -bill w

> > > astro.whwiii.net

> > >

> > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > >

> > > > thanks for the replies

> > > > i was able to reach ovision by telephone this AM

> > > > (my emails didn't get thru)

> > > > they suggested loosening the brass screw at one end slightly as well

> > > >

> > > > will let you know how it goes

> > > > of course it's raining now

> > > >

> > > > -bill w

> > > >

> > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > > >

> > > > > Hi Bill,

> > > > > I would think the preload is too tight. Mark the brass adjuster on the

> > > > > end then loosen it slightly and check for no lateral play. Then see if

> > > > > it turns smoothly.

> > > > > Another person had this problem but sent it back for replacement

> > > > > without trying to adjust it. I would bet that this is the problem, but

> > > > > it could be something else.

> > > > > My worm turned freely and smoothly when I tested it.

> > > > > Floyd

> > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > > >

> > > > > > thanks for your reply floyd

> > > > > > the oldham coupler looked well aligned

> > > > > > and the block square on installation

> > > > > > but will check again and cut down on the play a bit

> > > > > >

> > > > > > what are your thoughts on the worm not spinning smoothly?

> > > > > > it's hard to imaging smooth tracking with that

> > > > > >

> > > > > > -bill

> > > > > >

> > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > > > > >

> > > > > > > Check the Oldham coupler for its alignment. Adjust the worm so that

> > > > > > > you have 1mm play at the end of the counter weight shaft with the

> > > > > > > mount a room temp. Make sure the worm is square with both sides

> > > > having

> > > > > > > an equal spacing from the mount flange.

> > > > > > > Floyd

> > > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > > > > >

> > > > > > > > wups used main pixel scale instead of guider

> > > > > > > > the PE range is closer to +/- 5 arcsec (still not bad)

> > > > > > > > with jumps of 5-7 arc-sec in a second ;(

> > > > > > > > updated spread sheet

> > > > > > > >

> > > > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com, "fndnmonyhoo" mosg@>

> > > > wrote:

> > > > > > > > >

> > > > > > > > > well the good news is that

> > > > > > > > > eyeballing a correction for drift

> > > > > > > > > the range of my PE has been reduced from +/-30 to less than

> > > > > +/-3 arc

> > > > > > > > > seconds!

> > > > > > > > > (before PEC)

> > > > > > > > >

> > > > > > > > > the bad news is that the PE is very jagged

> > > > > > > > > jumping 3 arcsec and back over the course of a second or 2

> > > > > > > > > so my long focal length images are much worse now and very

> > > > > difficult

> > > > > > > > > to guide

> > > > > > > > > :(

> > > > > > > > >

> > > > > > > > > whwastro.

> > > whwastro.homestead.com/files/temp/ovision_PE_run.xls>

> > > homestead.com/files/temp/ovision_PE_run.xls

> > > > > > > > >

> > > > > > > > > i took great care installing the worm

> > > > > > > > > following the directions provided.

> > > > > > > > >

> > > > > > > > > i have two observations:

> > > > > > > > > 1. there's definitely more backlash now ~2mm

> > > > > > > > > there was almost none in the system with the original worm

> > > > > > > > > perhaps explaining the high PE range

> > > > > > > > > 2. the ovision worm assembly itself did not turn smoothly

> > > > (arrived

> > > > > > > > > like that).

> > > > > > > > >

> > > > > > > > > my guess/hope is that there's a bearing problem with the worm

> > > > > > assembly

> > > > > > > > > that could be easily corrected

> > > > > > > > >

> > > > > > > > > any suggestions would be appreciated

> > > > > > > > > ovision has not responded to my email

> > > > > > > > >

> > > > > > > > > thanks

> > > > > > > > >

> > > > > > > > > -bill w

> > > > > > > > >

> > > > > > > >

> > > > > > >

> > > > > >

> > > > >

> > > >

> > >

> > >

> > >

> > >

> > >

> > > [Non-text portions of this message have been removed]

> > >

> >

> >

> >

> >

> >

> > [Non-text portions of this message have been removed]

> >

>











[Non-text portions of this message have been removed]







----------------------------

#42605 Apr 24, 2009

Ian Taylor wrote: > In other words, I don't believe it is necessary, provided you use your mount regularly, it should run-in naturally.

>

It makes a difference that over a year an automobile engine would make

several million revolutions while over a year the polar axis of a

telescope would make a couple of hundred revolutions.



Bud



----------------------------

#42608 Apr 25, 2009

The fact that it is such a low speed will help running in. The lubricant film thickness between the gears will be very small at the low speeds encountered in the Losmandy gears. Most wear that occurs in a car occurs at starting and stopping - so although the car may experience millions of revs/year, it is only the first few revs at starting and stopping that will be important - most people only probably start their car around 4000 times per year.



Running in of the gears will also be helped if you load up the mount. If you don't have much weight on, then I agree it could take quite a while to run in.

--- In Losmandy_users@yahoogroups.com, William Hamblen wrhamblen@...> wrote:

>

> Ian Taylor wrote:

> > In other words, I don't believe it is necessary, provided you use your mount regularly, it should run-in naturally.

> >

> It makes a difference that over a year an automobile engine would make

> several million revolutions while over a year the polar axis of a

> telescope would make a couple of hundred revolutions.

>

> Bud

>



----------------------------

#42651 Apr 28, 2009

thanks for posting it roy

astounding that you got that PE out of the box, while i was +/- 18



well with the ovision worm and a heavier counter weight

i was able to tweak it down to a PE of +/- 6 with an RMS of 3



i guess it's time for PEC training

do you use that at all?



-bill



ps good luck with the mach1!

--- In Losmandy_users@yahoogroups.com, "Roy Cummings" tr_cummings@...> wrote:

>

> Place the PEMPro txt file in this groups file section in a folder called

> Cummings.

>

>

>

> Roy

>

>

>

>

>

> -----Original Message-----

> From: Losmandy_users@yahoogroups.com [mailto:Losmandy_users@yahoogroups.com]

> On Behalf Of fndnmonyhoo

> Sent: Thursday, April 23, 2009 12:34 AM

> To: Losmandy_users@yahoogroups.com

> Subject: [Losmandy_users] Re: ovision worm help-follow up

>

>

>

>

>

>

>

>

> sheesh your PE out of the box was almost 1/3 of mine

> i'm curious to see what the PEMPro data looks like

> if you don't mind sending it

>

> thanks

>

> --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com, "Roy Cummings" tr_cummings@> wrote:

> >

> > Hi Bill,

> >

> >

> >

> > Measured fixed worm block end distance to stop and adjusted right hand

> > (adjustable) block end to exact same. Used feeler gauges jammed in gap

> both

> > sides.

> >

> > These measurements were only at 1.98 arc/pixel plate scale 770mm FL. In

> > looking over the run I see the star used was saturated, this may be why

> the

> > results are so low. Last year (maybe longer) with a C8 F6.3 .98 arc/pixel

> > plate scale and the mount was very (before worm block adjustment) new the

> > results were +5.8 /-7.8. I can send you the PEMPro data file if you like.

> > The mount guides without problems at my current FL with 20min exposures as

> > the norm. I just came up on the AP list for a MACH1 have to make a

> decision

> > in the next few days if I still want to go that route.

> >

> >

> >

> > Roy

> >

> >

> >

> > -----Original Message-----

> > From: Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com [mailto:Losmandy_users@

> mailto:Losmandy_users%40yahoogroups.com> yahoogroups.com]

> > On Behalf Of fndnmonyhoo

> > Sent: Tuesday, April 21, 2009 9:02 PM

> > To: Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> yahoogroups.com

> > Subject: [Losmandy_users] Re: ovision worm help-follow up

> >

> >

> >

> >

> >

> >

> >

> >

> > how on earth did you get values that low?!

> >

> > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "Roy Cummings" tr_cummings@> wrote:

> > >

> > > Bill,

> > >

> > >

> > >

> > > Your original worm will have been run in from your use of the mount,

> these

> > > aren't bad worms just a good worm in a bad block.

> > >

> > > Your new worm will only get better as it is run in.

> > >

> > > My mount with original block and worm gives these results

> > >

> > >

> > >

> > > Peak PE+: 2.8 arcsecs

> > > Peak PE-: -3.8 arcsecs

> > > RMS PE: .877 arcsecs

> > >

> > > Worm Period PE: 1.45

> > > 76 second PE was .55

> > >

> > >

> > >

> > > Roy

> > >

> > >

> > >

> > > -----Original Message-----

> > > From: Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com [mailto:Losmandy_users@

> > mailto:Losmandy_users%40yahoogroups.com> yahoogroups.com]

> > > On Behalf Of fndnmonyhoo

> > > Sent: Tuesday, April 21, 2009 11:57 AM

> > > To: Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com

> > > Subject: [Losmandy_users] Re: ovision worm help-follow up

> > >

> > >

> > >

> > >

> > >

> > >

> > >

> > >

> > > just thought i'd give some follow up on my ovision worm

> > > the first worm seemed to have a problem with the bearings

> > > there was a very rough feeling when i rotated the worm by hand

> > > (when not installed)

> > > attempts to change the brass adjuster did not improve it

> > >

> > > i was sent a new worm with a new design from ovision

> > > it turns smoothly

> > > i installed it this weekend

> > > and my PE is much improved by virtue of elimination of the 76 second

> error

> > > which was very large.

> > >

> > > i analyzed my PE runs with PEC pro

> > > and found some interesting results:

> > > stock worm

> > > Peak PE+: 18.32 arcsecs

> > > Peak PE-: -18.36 arcsecs

> > > RMS PE: 7.48 arcsecs

> > > Av. PE+: 6.35 arcsecs

> > > Av. PE-: -6.15 arcsecs

> > > Max Delta+: 1.51 arcsecs

> > > Max Delta-: -1.40 arcsecs

> > > Av. Noise: 0.13 arcsecs

> > >

> > > ovision worm

> > > Peak PE+: 8.49 arcsecs

> > > Peak PE-: -8.20 arcsecs

> > > RMS PE: 3.79 arcsecs

> > > Av. PE+: 3.31 arcsecs

> > > Av. PE-: -3.06 arcsecs

> > > Max Delta+: 0.27 arcsecs

> > > Max Delta-: -0.30 arcsecs

> > > Av. Noise: 0.04 arcsecs

> > >

> > > looking at the frequency spectra

> > > for the old worm

> > > the 76 second predicted (calculated) PE was 17.1

> > > the primary worm PE was 8.8

> > > there was also a 117 second error of 8.8

> > > not sure what this last is

> > > it's close to worm bearing ball spin which has a period of 109?

> > >

> > > for the new worm

> > > the 76 second error is non existent

> > > the 117 second error is non existent

> > > however, the primary worm PE is 9.2

> > >

> > > so the good news is that my PE has been cut in half

> > > and it has the same period as the worm

> > > so it should be amenable to PEC, perhaps halving the PE

> > >

> > > but shouldn't the primary PE of the worm

> > > be lower with a high precision worm?

> > >

> > > -bill w

> > > astro.whwiii.net

> > >

> > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > >

> > > > thanks for the replies

> > > > i was able to reach ovision by telephone this AM

> > > > (my emails didn't get thru)

> > > > they suggested loosening the brass screw at one end slightly as well

> > > >

> > > > will let you know how it goes

> > > > of course it's raining now

> > > >

> > > > -bill w

> > > >

> > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > > >

> > > > > Hi Bill,

> > > > > I would think the preload is too tight. Mark the brass adjuster on

> the

> > > > > end then loosen it slightly and check for no lateral play. Then see

> if

> > > > > it turns smoothly.

> > > > > Another person had this problem but sent it back for replacement

> > > > > without trying to adjust it. I would bet that this is the problem,

> but

> > > > > it could be something else.

> > > > > My worm turned freely and smoothly when I tested it.

> > > > > Floyd

> > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > > >

> > > > > > thanks for your reply floyd

> > > > > > the oldham coupler looked well aligned

> > > > > > and the block square on installation

> > > > > > but will check again and cut down on the play a bit

> > > > > >

> > > > > > what are your thoughts on the worm not spinning smoothly?

> > > > > > it's hard to imaging smooth tracking with that

> > > > > >

> > > > > > -bill

> > > > > >

> > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > > > > >

> > > > > > > Check the Oldham coupler for its alignment. Adjust the worm so

> > that

> > > > > > > you have 1mm play at the end of the counter weight shaft with

> the

> > > > > > > mount a room temp. Make sure the worm is square with both sides

> > > > having

> > > > > > > an equal spacing from the mount flange.

> > > > > > > Floyd

> > > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > > > > >

> > > > > > > > wups used main pixel scale instead of guider

> > > > > > > > the PE range is closer to +/- 5 arcsec (still not bad)

> > > > > > > > with jumps of 5-7 arc-sec in a second ;(

> > > > > > > > updated spread sheet

> > > > > > > >

> > > > > > > > --- In Losmandy_users@

> mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com, "fndnmonyhoo" mosg@>

> > > > wrote:

> > > > > > > > >

> > > > > > > > > well the good news is that

> > > > > > > > > eyeballing a correction for drift

> > > > > > > > > the range of my PE has been reduced from +/-30 to less than

> > > > > +/-3 arc

> > > > > > > > > seconds!

> > > > > > > > > (before PEC)

> > > > > > > > >

> > > > > > > > > the bad news is that the PE is very jagged

> > > > > > > > > jumping 3 arcsec and back over the course of a second or 2

> > > > > > > > > so my long focal length images are much worse now and very

> > > > > difficult

> > > > > > > > > to guide

> > > > > > > > > :(

> > > > > > > > >

> > > > > > > > > whwastro.

> > > whwastro.

> > whwastro.

> whwastro.homestead.com/files/temp/ovision_PE_run.xls>

> homestead.com/files/temp/ovision_PE_run.xls>

> > homestead.com/files/temp/ovision_PE_run.xls>

> > > homestead.com/files/temp/ovision_PE_run.xls

> > > > > > > > >

> > > > > > > > > i took great care installing the worm

> > > > > > > > > following the directions provided.

> > > > > > > > >

> > > > > > > > > i have two observations:

> > > > > > > > > 1. there's definitely more backlash now ~2mm

> > > > > > > > > there was almost none in the system with the original worm

> > > > > > > > > perhaps explaining the high PE range

> > > > > > > > > 2. the ovision worm assembly itself did not turn smoothly

> > > > (arrived

> > > > > > > > > like that).

> > > > > > > > >

> > > > > > > > > my guess/hope is that there's a bearing problem with the

> worm

> > > > > > assembly

> > > > > > > > > that could be easily corrected

> > > > > > > > >

> > > > > > > > > any suggestions would be appreciated

> > > > > > > > > ovision has not responded to my email

> > > > > > > > >

> > > > > > > > > thanks

> > > > > > > > >

> > > > > > > > > -bill w

> > > > > > > > >

> > > > > > > >

> > > > > > >

> > > > > >

> > > > >

> > > >

> > >

> > >

> > >

> > >

> > >

> > > [Non-text portions of this message have been removed]

> > >

> >

> >

> >

> >

> >

> > [Non-text portions of this message have been removed]

> >

>

>

>

>

>

> [Non-text portions of this message have been removed]

>







----------------------------

#42652 Apr 29, 2009

Bill,



I didn't mean to miss-lead you. My out of the box PE was something like +5.8 -7.8 PP=13.6 and that trained down to a PP of less than 5.

At that time I was imaging @ F6.3 with a C8 1280mm FL ST2000XM with 7.4um pixels .95arcsec/pixel. Since that time I adjusted the alignment of the worm to worm-wheel trying to get the pair as perpendicular as I could with feeler gauges. The imaging package has changed and is heaver now. Imaging equipment now is FLT110wTMBFF-VanSlyke 3in focuser ST4000XCM/AO8 side-by-side with TV76wRF2008-Moonlight 2" focuser ST2000XM/CFW8a. I always keep the package loaded east about 2-5lbs. This is not your seldom-used mount either; it is in my observatory and is running 6 to 8 hours almost every clear night. This G11 is nicely adjusted and well run-in.

Had to pass on the MACH1 hard to justify that in these times, given the performance of my G11.



Roy



--- In Losmandy_users@yahoogroups.com, "fndnmonyhoo" mosg@...> wrote:

>

> thanks for posting it roy

> astounding that you got that PE out of the box, while i was +/- 18

>

> well with the ovision worm and a heavier counter weight

> i was able to tweak it down to a PE of +/- 6 with an RMS of 3

>

> i guess it's time for PEC training

> do you use that at all?

>

> -bill

>

> ps good luck with the mach1!

>

> --- In Losmandy_users@yahoogroups.com, "Roy Cummings" tr_cummings@> wrote:

> >

> > Place the PEMPro txt file in this groups file section in a folder called

> > Cummings.

> >

> >

> >

> > Roy

> >

> >

> >

> >

> >

> > -----Original Message-----

> > From: Losmandy_users@yahoogroups.com [mailto:Losmandy_users@yahoogroups.com]

> > On Behalf Of fndnmonyhoo

> > Sent: Thursday, April 23, 2009 12:34 AM

> > To: Losmandy_users@yahoogroups.com

> > Subject: [Losmandy_users] Re: ovision worm help-follow up

> >

> >

> >

> >

> >

> >

> >

> >

> > sheesh your PE out of the box was almost 1/3 of mine

> > i'm curious to see what the PEMPro data looks like

> > if you don't mind sending it

> >

> > thanks

> >

> > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com, "Roy Cummings" tr_cummings@> wrote:

> > >

> > > Hi Bill,

> > >

> > >

> > >

> > > Measured fixed worm block end distance to stop and adjusted right hand

> > > (adjustable) block end to exact same. Used feeler gauges jammed in gap

> > both

> > > sides.

> > >

> > > These measurements were only at 1.98 arc/pixel plate scale 770mm FL. In

> > > looking over the run I see the star used was saturated, this may be why

> > the

> > > results are so low. Last year (maybe longer) with a C8 F6.3 .98 arc/pixel

> > > plate scale and the mount was very (before worm block adjustment) new the

> > > results were +5.8 /-7.8. I can send you the PEMPro data file if you like.

> > > The mount guides without problems at my current FL with 20min exposures as

> > > the norm. I just came up on the AP list for a MACH1 have to make a

> > decision

> > > in the next few days if I still want to go that route.

> > >

> > >

> > >

> > > Roy

> > >

> > >

> > >

> > > -----Original Message-----

> > > From: Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com [mailto:Losmandy_users@

> > mailto:Losmandy_users%40yahoogroups.com> yahoogroups.com]

> > > On Behalf Of fndnmonyhoo

> > > Sent: Tuesday, April 21, 2009 9:02 PM

> > > To: Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > yahoogroups.com

> > > Subject: [Losmandy_users] Re: ovision worm help-follow up

> > >

> > >

> > >

> > >

> > >

> > >

> > >

> > >

> > > how on earth did you get values that low?!

> > >

> > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com, "Roy Cummings" tr_cummings@> wrote:

> > > >

> > > > Bill,

> > > >

> > > >

> > > >

> > > > Your original worm will have been run in from your use of the mount,

> > these

> > > > aren't bad worms just a good worm in a bad block.

> > > >

> > > > Your new worm will only get better as it is run in.

> > > >

> > > > My mount with original block and worm gives these results

> > > >

> > > >

> > > >

> > > > Peak PE+: 2.8 arcsecs

> > > > Peak PE-: -3.8 arcsecs

> > > > RMS PE: .877 arcsecs

> > > >

> > > > Worm Period PE: 1.45

> > > > 76 second PE was .55

> > > >

> > > >

> > > >

> > > > Roy

> > > >

> > > >

> > > >

> > > > -----Original Message-----

> > > > From: Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com [mailto:Losmandy_users@

> > > mailto:Losmandy_users%40yahoogroups.com> yahoogroups.com]

> > > > On Behalf Of fndnmonyhoo

> > > > Sent: Tuesday, April 21, 2009 11:57 AM

> > > > To: Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > yahoogroups.com

> > > > Subject: [Losmandy_users] Re: ovision worm help-follow up

> > > >

> > > >

> > > >

> > > >

> > > >

> > > >

> > > >

> > > >

> > > > just thought i'd give some follow up on my ovision worm

> > > > the first worm seemed to have a problem with the bearings

> > > > there was a very rough feeling when i rotated the worm by hand

> > > > (when not installed)

> > > > attempts to change the brass adjuster did not improve it

> > > >

> > > > i was sent a new worm with a new design from ovision

> > > > it turns smoothly

> > > > i installed it this weekend

> > > > and my PE is much improved by virtue of elimination of the 76 second

> > error

> > > > which was very large.

> > > >

> > > > i analyzed my PE runs with PEC pro

> > > > and found some interesting results:

> > > > stock worm

> > > > Peak PE+: 18.32 arcsecs

> > > > Peak PE-: -18.36 arcsecs

> > > > RMS PE: 7.48 arcsecs

> > > > Av. PE+: 6.35 arcsecs

> > > > Av. PE-: -6.15 arcsecs

> > > > Max Delta+: 1.51 arcsecs

> > > > Max Delta-: -1.40 arcsecs

> > > > Av. Noise: 0.13 arcsecs

> > > >

> > > > ovision worm

> > > > Peak PE+: 8.49 arcsecs

> > > > Peak PE-: -8.20 arcsecs

> > > > RMS PE: 3.79 arcsecs

> > > > Av. PE+: 3.31 arcsecs

> > > > Av. PE-: -3.06 arcsecs

> > > > Max Delta+: 0.27 arcsecs

> > > > Max Delta-: -0.30 arcsecs

> > > > Av. Noise: 0.04 arcsecs

> > > >

> > > > looking at the frequency spectra

> > > > for the old worm

> > > > the 76 second predicted (calculated) PE was 17.1

> > > > the primary worm PE was 8.8

> > > > there was also a 117 second error of 8.8

> > > > not sure what this last is

> > > > it's close to worm bearing ball spin which has a period of 109?

> > > >

> > > > for the new worm

> > > > the 76 second error is non existent

> > > > the 117 second error is non existent

> > > > however, the primary worm PE is 9.2

> > > >

> > > > so the good news is that my PE has been cut in half

> > > > and it has the same period as the worm

> > > > so it should be amenable to PEC, perhaps halving the PE

> > > >

> > > > but shouldn't the primary PE of the worm

> > > > be lower with a high precision worm?

> > > >

> > > > -bill w

> > > > astro.whwiii.net

> > > >

> > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > >

> > > > > thanks for the replies

> > > > > i was able to reach ovision by telephone this AM

> > > > > (my emails didn't get thru)

> > > > > they suggested loosening the brass screw at one end slightly as well

> > > > >

> > > > > will let you know how it goes

> > > > > of course it's raining now

> > > > >

> > > > > -bill w

> > > > >

> > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > > yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > > > >

> > > > > > Hi Bill,

> > > > > > I would think the preload is too tight. Mark the brass adjuster on

> > the

> > > > > > end then loosen it slightly and check for no lateral play. Then see

> > if

> > > > > > it turns smoothly.

> > > > > > Another person had this problem but sent it back for replacement

> > > > > > without trying to adjust it. I would bet that this is the problem,

> > but

> > > > > > it could be something else.

> > > > > > My worm turned freely and smoothly when I tested it.

> > > > > > Floyd

> > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > > > >

> > > > > > > thanks for your reply floyd

> > > > > > > the oldham coupler looked well aligned

> > > > > > > and the block square on installation

> > > > > > > but will check again and cut down on the play a bit

> > > > > > >

> > > > > > > what are your thoughts on the worm not spinning smoothly?

> > > > > > > it's hard to imaging smooth tracking with that

> > > > > > >

> > > > > > > -bill

> > > > > > >

> > > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > > yahoogroups.com, "Floyd Blue" fblue@> wrote:

> > > > > > > >

> > > > > > > > Check the Oldham coupler for its alignment. Adjust the worm so

> > > that

> > > > > > > > you have 1mm play at the end of the counter weight shaft with

> > the

> > > > > > > > mount a room temp. Make sure the worm is square with both sides

> > > > > having

> > > > > > > > an equal spacing from the mount flange.

> > > > > > > > Floyd

> > > > > > > > --- In Losmandy_users@ mailto:Losmandy_users%40yahoogroups.com>

> > > > yahoogroups.com, "fndnmonyhoo" mosg@> wrote:

> > > > > > > > >

> > > > > > > > > wups used main pixel scale instead of guider

> > > > > > > > > the PE range is closer to +/- 5 arcsec (still not bad)

> > > > > > > > > with jumps of 5-7 arc-sec in a second ;(

> > > > > > > > > updated spread sheet

> > > > > > > > >

> > > > > > > > > --- In Losmandy_users@

> > mailto:Losmandy_users%40yahoogroups.com>

> > > > yahoogroups.com, "fndnmonyhoo" mosg@>

> > > > > wrote:

> > > > > > > > > >

> > > > > > > > > > well the good news is that

> > > > > > > > > > eyeballing a correction for drift

> > > > > > > > > > the range of my PE has been reduced from +/-30 to less than

> > > > > > +/-3 arc

> > > > > > > > > > seconds!

> > > > > > > > > > (before PEC)

> > > > > > > > > >

> > > > > > > > > > the bad news is that the PE is very jagged

> > > > > > > > > > jumping 3 arcsec and back over the course of a second or 2

> > > > > > > > > > so my long focal length images are much worse now and very

> > > > > > difficult

> > > > > > > > > > to guide

> > > > > > > > > > :(

> > > > > > > > > >

> > > > > > > > > > whwastro.

> > > > whwastro.

> > > whwastro.

> > whwastro.homestead.com/files/temp/ovision_PE_run.xls>

> > homestead.com/files/temp/ovision_PE_run.xls>

> > > homestead.com/files/temp/ovision_PE_run.xls>

> > > > homestead.com/files/temp/ovision_PE_run.xls

> > > > > > > > > >

> > > > > > > > > > i took great care installing the worm

> > > > > > > > > > following the directions provided.

> > > > > > > > > >

> > > > > > > > > > i have two observations:

> > > > > > > > > > 1. there's definitely more backlash now ~2mm

> > > > > > > > > > there was almost none in the system with the original worm

> > > > > > > > > > perhaps explaining the high PE range

> > > > > > > > > > 2. the ovision worm assembly itself did not turn smoothly

> > > > > (arrived

> > > > > > > > > > like that).

> > > > > > > > > >

> > > > > > > > > > my guess/hope is that there's a bearing problem with the

> > worm

> > > > > > > assembly

> > > > > > > > > > that could be easily corrected

> > > > > > > > > >

> > > > > > > > > > any suggestions would be appreciated

> > > > > > > > > > ovision has not responded to my email

> > > > > > > > > >

> > > > > > > > > > thanks

> > > > > > > > > >

> > > > > > > > > > -bill w

> > > > > > > > > >

> > > > > > > > >

> > > > > > > >

> > > > > > >

> > > > > >

> > > > >

> > > >

> > > >

> > > >

> > > >

> > > >

> > > > [Non-text portions of this message have been removed]

> > > >

> > >

> > >

> > >

> > >

> > >

> > > [Non-text portions of this message have been removed]

> > >

> >

> >

> >

> >

> >

> > [Non-text portions of this message have been removed]

> >

>







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