VintageBigBlue.org

 

Re: phd or mount problem?


Dec 28, 2002

 


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

#13282 Dec 28, 2002

After months og going round and around, I believe I got my C-9.25

dovetail problem worked. This is what was wrong. I could NOT mount

the Losmandy C-9.25 dovetail on the right side of th eC-9.25.



Source of problem: One bracket had holes too far apart to use the

7/8 in. spaced mounting holes on the rear of the C-9.25 where the

original dovetai went. I had to use the other side of the tube, thus

making it impossible to mount finder.



I sent bracket in question back to Scott for re-doing. Now, when

lining up dovetail, another problem: If Back bracket with dovetail

is attached, the way to (from Scott) align is to moung dovetail to

front bracket, then center and tighten THROUGH the dovetsil. Problem

is, there is NOT a center hole in either end of the dovetail that is

in alignment with the holes for mounting the dovetail to the brackets.



It seems odd to me that with what one pays, the parts ought to fit

the first time, without any additional alterations. I will need to

machine-out a hole in the front end of the dovetail, on center and in

line with dovetail mounting holes.



Anyways, it took a long time to get some people convinced there was a

problem. Now, if only I can get the Telrad mount off the C-9.25

where the dovetail must now go, without breaking it.



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

#14603 Mar 31, 2003

I have a C-11 mounted on top of a G-11 Losmandy mount. I attach

a 9x50 spotting scope, a Telrad, a metal dew shield, a 2"

diameter 90 degree bend, and a 2" diameter eyepiece to the scope.

I use 2, eleven pound counter balance weights which are

positioned fully down on the shaft. The mount is about 2 years

old and has the original stepper motors.



My problem is that the movement on the RA axis is hesitant and

jerky when I press the RA button on the hand controller. This

problem has just recently appeared. I use a 3 amp, 12-volt power

supply which actually produces 13.8 volts with no load.



Does any ideas what the problem is and how to fix it (other than

upgrading to the Gemini)?



Jim Benet

OCA Outreach Coordinator

email: jimbenet@...

Home Phone: (714) 693-1639

Cell Phone: (714) 931-1639

:-)



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

#15327 May 17, 2003

I would like suggestions on how to fix a problem I have with my Losmandy

G-11 mount.



The RA motor is intermittent and sometimes doesn't track. When I advance

the RA with the hand controller, there is a 2 to 3 second delay before is

starts moving. When it does move, I noticed that the movement was rather

jerking -- moving then stopping then moving again. If I swap the RA and Dec

cables and push the hand controller buttons, the problem still persists with

the RA motor, but Dec motor always works fine (no matter which cable is

driving the motor).



This problem occurs when I first start using the mount. After about a half

hour, it seems to work properly. Could this be a gear problem? If so, how

do I fix it? Should I send the mount back to Losmandy for service?



The mount is about 3 years old with the original motors. I have it loaded

with a C-11 scope, 2-inch diameter diagonal and optics, a Telrad, and a

metal dew shield. I use two 11-pound counter weights place near the end of

the counter-weight shaft. The scope is balanced before using the telescope.



Jim Benet



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

#15329 May 18, 2003

Jim,



The RA motor shaft, is connected to the worm gear via an oldham

coupler.



It's possible that this coupler, has become loose on end or the

other.



Remove the RA worm cover, and watch the motor shaft as well as the

worm shaft while using your handcontroller to slew the scope one way

or the other in RA.



If you are slewing at slow speeds (say 32X or slower), then you can

stick an allen wrench into one of the set-screws of the oldham

coupler (there are two on each side) and watch the allen wrench to

see if it is moving (it will draw a much larger arc than the coupler

itself, and makes it easier to detect movement).



It the coupler is loose, just gently snug down all the set-screws.

Not a lot of torque is required, and these small set-screws are easy

to strip, so exercise some care.



Take Care,





--- In Losmandy_users@yahoogroups.com, "jimbenet" jimbenet@p...>

wrote: > I would like suggestions on how to fix a problem I have with my

Losmandy > G-11 mount.

>

> The RA motor is intermittent and sometimes doesn't track. When I

advance > the RA with the hand controller, there is a 2 to 3 second delay

before is > starts moving. When it does move, I noticed that the movement was

rather > jerking -- moving then stopping then moving again. If I swap the

RA and Dec > cables and push the hand controller buttons, the problem still

persists with > the RA motor, but Dec motor always works fine (no matter which

cable is > driving the motor).

>

> This problem occurs when I first start using the mount. After

about a half > hour, it seems to work properly. Could this be a gear problem?

If so, how > do I fix it? Should I send the mount back to Losmandy for service?

>

> The mount is about 3 years old with the original motors. I have

it loaded > with a C-11 scope, 2-inch diameter diagonal and optics, a Telrad,

and a > metal dew shield. I use two 11-pound counter weights place near

the end of > the counter-weight shaft. The scope is balanced before using the

telescope. >

> Jim Benet







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

#15365 May 22, 2003

James-



Thanks for your suggestion. The coupling wasn't the problem; however, your

suggestion led me to the problem.



I removed the cover and checked the set screws. They were all tight. Then

I activated the hand controller and noticed that the motor itself was not

moving. I check the voltage on the battery as I pressed the hand

controller. I measured only 10.3 volts under load. I then switched to my

13.8-volt power supply. Everything worked fine then.



It turns out that my battery is no longer holding a charge. I think I have

to get a new one. I was using a Power Sonic 7 amp-hour gel cell battery.

Maybe I should go with a battery with a larger capacity. Perhaps I can find

something at RTMC this weekend.



Thanks again for your help.



Jim Benet





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

From: cjl023 [mailto:james.lacey@...]

Sent: Sunday, May 18, 2003 5:37 AM

To: Losmandy_users@yahoogroups.com

Subject: [Losmandy_users] Re: Mount Problem





Jim,



The RA motor shaft, is connected to the worm gear via an oldham

coupler.



It's possible that this coupler, has become loose on end or the

other.



Remove the RA worm cover, and watch the motor shaft as well as the

worm shaft while using your handcontroller to slew the scope one way

or the other in RA.



If you are slewing at slow speeds (say 32X or slower), then you can

stick an allen wrench into one of the set-screws of the oldham

coupler (there are two on each side) and watch the allen wrench to

see if it is moving (it will draw a much larger arc than the coupler

itself, and makes it easier to detect movement).



It the coupler is loose, just gently snug down all the set-screws.

Not a lot of torque is required, and these small set-screws are easy

to strip, so exercise some care.



Take Care,





--- In Losmandy_users@yahoogroups.com, "jimbenet" jimbenet@p...>

wrote: > I would like suggestions on how to fix a problem I have with my

Losmandy > G-11 mount.

>

> The RA motor is intermittent and sometimes doesn't track. When I

advance > the RA with the hand controller, there is a 2 to 3 second delay

before is > starts moving. When it does move, I noticed that the movement was

rather > jerking -- moving then stopping then moving again. If I swap the

RA and Dec > cables and push the hand controller buttons, the problem still

persists with > the RA motor, but Dec motor always works fine (no matter which

cable is > driving the motor).

>

> This problem occurs when I first start using the mount. After

about a half > hour, it seems to work properly. Could this be a gear problem?

If so, how > do I fix it? Should I send the mount back to Losmandy for service?

>

> The mount is about 3 years old with the original motors. I have

it loaded > with a C-11 scope, 2-inch diameter diagonal and optics, a Telrad,

and a > metal dew shield. I use two 11-pound counter weights place near

the end of > the counter-weight shaft. The scope is balanced before using the

telescope. >

> Jim Benet







To unsubscribe from this group, send an email to:

Losmandy_users-unsubscribe@egroups.com







Your use of Yahoo! Groups is subject to docs.yahoo.com/info/terms/



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

#16184 Jul 15, 2003

I have an original Losmandy GM-100 mount on which I have mounted a C-

8. I am using an SBIG STV to guide for imaging. I am experiencing

guiding spikes at regulare intervals within the 4 min worm period.

The intensity of the spikes vary by the focal length of the guiding

scope. If I attach the STV to a mini-Borg (250 mm), the spikes can

be as much as +/-5. If I use a 400mm refractor, they have been +/-3.

At f/6.3 on the C-8, they are around 1.5. I had someone in my club

re-lap the worm and check the gears in the RA motor. Did not help. I

have uploaded an off polar-aligned star image taken with the STV (7

min at 1280 mm, 320 x 200 pixels) showing my periodic error. I also

created a graph from that image. They are in the JohnD_PE folder. I

have calculated my periodic error to be about 10" but the graph is

very uneven.

Any suggestions would be appreciated.



JohnD



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

#16189 Jul 16, 2003

John;



Have you tried guiding with a ST-4 or some other CCD besides another

STV to compare your results?...joe :)





"May You Go Among The Imperishable Stars"



Joe Mize: www.svic.net/jmize

Chiefland, FL 29:24'33.4"N 82:51'37.7"W

Moon Phase: tycho.usno.navy.mil/cgi-bin/phase.gif

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

From: "j_dwyer99" j-dwyer@...>

To: Losmandy_users@yahoogroups.com>

Sent: Tuesday, July 15, 2003 11:43 PM

Subject: [Losmandy_users] Mount Problems





> I have an original Losmandy GM-100 mount on which I have mounted a C-

> 8. I am using an SBIG STV to guide for imaging. I am experiencing

> guiding spikes at regulare intervals within the 4 min worm period.

> The intensity of the spikes vary by the focal length of the guiding

> scope. If I attach the STV to a mini-Borg (250 mm), the spikes can

> be as much as +/-5. If I use a 400mm refractor, they have been +/-3.

> At f/6.3 on the C-8, they are around 1.5. I had someone in my club

> re-lap the worm and check the gears in the RA motor. Did not help. I

> have uploaded an off polar-aligned star image taken with the STV (7

> min at 1280 mm, 320 x 200 pixels) showing my periodic error. I also

> created a graph from that image. They are in the JohnD_PE folder. I

> have calculated my periodic error to be about 10" but the graph is

> very uneven.

> Any suggestions would be appreciated.

>

> JohnD

>

>

>

> To unsubscribe from this group, send an email to:

> Losmandy_users-unsubscribe@egroups.com

>

>

>

> Your use of Yahoo! Groups is subject to docs.yahoo.com/info/terms/

>

>

>







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

#16192 Jul 16, 2003

joe wrote: >

> John;

>

> Have you tried guiding with a ST-4 or some other CCD besides another

> STV to compare your results?...joe :)



John,



I would have to agree with Joe here. The STV is somewhat prone to this

on some pretty high-end mounts and a few have even sold them to go back

to other means. So if you have access to an ST-4 then try that. I have a

GM-100 with the HP Gearset and ST-4 and even overloaded it tracks very

well unless windy. And then I wouldn't expect it to.



Regards



Bill





--

William R. Mattil.| Fred Astaire wasn't so great.

wrmattil@....| Ginger had to do it all backwards

(972) 399-4106..| and... in high heels.



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

#16193 Jul 16, 2003

j_dwyer99 wrote: >



Let me make a stab at this John,

> I have an original Losmandy GM-100 mount on which I have mounted a C-

> 8. I am using an SBIG STV to guide for imaging. I am experiencing

> guiding spikes at regulare intervals within the 4 min worm period.

> The intensity of the spikes vary by the focal length of the guiding

> scope.



I would expect this to be the case. The longer the focal length the

greater the apparent error.

> If I attach the STV to a mini-Borg (250 mm), the spikes can

> be as much as +/-5. If I use a 400mm refractor, they have been +/-3.

> At f/6.3 on the C-8, they are around 1.5.



Huh ???????? Warning Bells are sounding on this one. The longer focal

length instrument should give you greater granularity and thus if the

error is actually present in the mount it should be greater with the C8

(longest focal length). Either this is backwards or something else is

wrong.

> I had someone in my club

> re-lap the worm and check the gears in the RA motor. Did not help. I

> have uploaded an off polar-aligned star image taken with the STV (7

> min at 1280 mm, 320 x 200 pixels) showing my periodic error. I also

> created a graph from that image. They are in the JohnD_PE folder. I

> have calculated my periodic error to be about 10" but the graph is

> very uneven.



My experience is that having the guiding instruments focal length

somewhat close to that of the imaging instrument provides the best

results. But that is using an ST-4. The STV has the efinder option that

supposedly will allow consistant tracking with relatively short focal

length. Not having an STV I cannot confirm, nor deny this.



What do your pictures (images) actually look like ? One of the local

users of an STV (AP155/AP1200) pretty much ignores the tracking errors

that the STV reports because he doesn't see them on the images. His STV

will sometimes oscillate in Dec and he spent a lot of time and film

trying to resolve it and hasn't.



So my instinct is to ask "Do you see a problem other than the tracking

report that the STV gives you ?"



"Can you confirm visually that this PE error actually exists and is

magnitude?"



"What configuration options on the STV have you tried ?" My

understanding from watching my imaging partner is that there is a very

real learning curve to the STV. Much worse than that of the ST-4.



Just some additional random thoughts ....



Regards



Bill



--

William R. Mattil.| Fred Astaire wasn't so great.

wrmattil@....| Ginger had to do it all backwards

(972) 399-4106..| and... in high heels.



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

#16194 Jul 16, 2003

I guess the question I have is: Are the refractors you mention mounted

on top of the C8 as guide scopes??



As Bill mentions, did you reverse the numbers?? If there's a problem,

it would certainly be most pronounced through an f/10 C8....



If those errors ARE correct-- it could be some issues with the mounting

rings, or focuser slop, or some other mechanical issue associated with

the way those scopes are mounted rather than the RA drive.



10" sounds pretty bad..... Hope it's not so!



Good luck!

Bob



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

From: "William R. Mattil" wrmattil@...>

Date: Wednesday, July 16, 2003 1:01 pm

Subject: Re: [Losmandy_users] Mount Problems



> span>p>span>p>

>

>

> tt>

> j_dwyer99 wrote:

>

> >

>

>

>

> Let me make a stab at this John,

>

>

>

> > I have an original Losmandy GM-100 mount on which I have

> mounted a C-

>

> > 8. I am using an SBIG STV to guide for imaging. I am experiencing

>

> > guiding spikes at regulare intervals within the 4 min worm

> period.

> > The intensity of the spikes vary by the focal length of the

> guiding

> > scope.

>

>

>

> I would expect this to be the case. The longer the focal length the

>

> greater the apparent error.

>

>

>

> > If I attach the STV to a mini-Borg (250 mm), the spikes can

>

> > be as much as +/-5. If I use a 400mm refractor, they have

> been +/-3.

>

> > At f/6.3 on the C-8, they are around 1.5.

>

>

>

> Huh ???????? Warning Bells are sounding on this one. The longer focal

>

> length instrument should give you greater granularity and thus if the

>

> error is actually present in the mount it should be greater with

> the C8

>

> (longest focal length). Either this is backwards or something else is

>

> wrong.

>

>

>

> > I had someone in my club

>

> > re-lap the worm and check the gears in the RA motor. Did not

> help. I

>

> > have uploaded an off polar-aligned star image taken with the

> STV (7

>

> > min at 1280 mm, 320 x 200 pixels) showing my periodic error.

> I also

>

> > created a graph from that image. They are in the JohnD_PE

> folder. I

>

> > have calculated my periodic error to be about 10" but

> the graph is

>

> > very uneven.

>

>

>

> My experience is that having the guiding instruments focal length

>

> somewhat close to that of the imaging instrument provides the best

>

> results. But that is using an ST-4. The STV has the efinder option

> that

> supposedly will allow consistant tracking with relatively short focal

>

> length. Not having an STV I cannot confirm, nor deny this.

>

>

>

> What do your pictures (images) actually look like ? One of the local

>

> users of an STV (AP155/AP1200) pretty much ignores the tracking errors

>

> that the STV reports because he doesn't see them on the images.

> His STV

>

> will sometimes oscillate in Dec and he spent a lot of time and film

>

> trying to resolve it and hasn't.

>

>

>

> So my instinct is to ask "Do you see a problem other than the

> tracking

> report that the STV gives you ?"

>

>

>

> "Can you confirm visually that this PE error actually exists

> and is

>

> magnitude?"

>

>

>

> "What configuration options on the STV have you tried ?" My

>

> understanding from watching my imaging partner is that there is a very

>

> real learning curve to the STV. Much worse than that of the ST-4.

>

>

>

> Just some additional random thoughts ....

>

>

>

> Regards

>

>

>

> Bill

>

>

>

> --

>

> William R. Mattil | Fred Astaire wasn't so great.

>

> wrmattil@... | Ginger had to do it all backwards

>

> (972) 399-4106 | and... in high heels.

>

> /tt>

>

>

>

>

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

#16197 Jul 16, 2003

Hi guys,



Thanks for your responses. I will try to respond to your comments.



1) I have not tried the ST-4 at this point. That is a thought. I can

try to contact a club member who has one to see if I can borrow it

and see if I get the same results. I actually had one several years

ago but did not get much of a chance to use it. I dont recall the

tracking accuracy of it. I found it was a little difficult to use at

times. That is why I went with the STV. I find it is much easier to

use as far as finding guide stars and focusing. It is also great for

displaying objects on the video screen at public star parties. It

does have more tracking adjustment options available than the ST-4.

You have to be certain you enter your guiding scope parameters for

it to calibrate and track properly. In addition to X/Y axis

aggessiveness adjustment, it has a "Maximum Correction" option

(which limits the amount of any adjustments) and "Exposures to Avg"

(which can average a number of exposures before making an

adjustment). I have tried all the tracking options.



2) The size of errors being inverse to the focal length have been

reported by other STV users. The eFinder mode supposedly can track

to within a 1" accuracy. Some people have been able to use this mode

with great success.



3) I am aware of the issues with the STV. It has been driving a lot

of people crazy (including me). I have a fellow club member who has

an AP1200 which exhibits spikes although he claims it is in RA not

Dec.



4) I have seen problems in images due to the tracking errors. The PE

image and graph of my mount seems to show some points where there

are some sharper changes in movement. As I recall the GM-100 was

rated at about 9" when it first casme out. I have the guide scopes

mounted on top of the C-8 using a 1/4-20 piggyback mount adapter.

I have considered possible issues with the mounting of the guide

scopes, but the precise regularity of the errors seem to point

elsewhere.



JohnD



--- In Losmandy_users@yahoogroups.com, "j_dwyer99" j-dwyer@a...>

wrote: > I have an original Losmandy GM-100 mount on which I have mounted a

C- > 8. I am using an SBIG STV to guide for imaging. I am experiencing

> guiding spikes at regulare intervals within the 4 min worm period.

> The intensity of the spikes vary by the focal length of the

guiding > scope. If I attach the STV to a mini-Borg (250 mm), the spikes can

> be as much as +/-5. If I use a 400mm refractor, they have been +/-

3. > At f/6.3 on the C-8, they are around 1.5. I had someone in my club

> re-lap the worm and check the gears in the RA motor. Did not help.

I > have uploaded an off polar-aligned star image taken with the STV

(7 > min at 1280 mm, 320 x 200 pixels) showing my periodic error. I

also > created a graph from that image. They are in the JohnD_PE folder.

I > have calculated my periodic error to be about 10" but the graph is

> very uneven.

> Any suggestions would be appreciated.

>

> JohnD



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

#16198 Jul 16, 2003

j_dwyer99 wrote: >

> Hi guys,

>

> Thanks for your responses. I will try to respond to your comments.

>

> 1) I have not tried the ST-4 at this point. That is a thought. I can

> try to contact a club member who has one to see if I can borrow it

> and see if I get the same results. I actually had one several years

> ago but did not get much of a chance to use it. I dont recall the

> tracking accuracy of it. I found it was a little difficult to use at

> times.



I find this hard to believe John. The ST-4 is a breeze. The first night

I used it was tracking just fine. But read on. There are some other

issues/items to consider.

> That is why I went with the STV. I find it is much easier to

> use as far as finding guide stars and focusing.



This *may* be :^) But FWIW there isn't IMHO a free lunch when it comes

to Astrophotography. It requires attention to detail.

> It is also great for

> displaying objects on the video screen at public star parties. It

> does have more tracking adjustment options available than the ST-4.

> You have to be certain you enter your guiding scope parameters for

> it to calibrate and track properly.



Not on the ST-4 .... you must be talking about the STV here. My ST-4

works straight up with my GM-100. Assuming appropriate guide star

paramters of course. If I am taking integrations of less than 1 sec I

will turn on AA (Average Adjust) to average two or three iterations. The

GM-100 is fine up to 2 sec. The Sa (Scintallation Adjust *must* be set

on 8 or greater to start. You can lower this once it is assured that the

seeing is excellent. Not often the case :^(

> In addition to X/Y axis

> aggessiveness adjustment, it has a "Maximum Correction" option

> (which limits the amount of any adjustments) and "Exposures to Avg"

> (which can average a number of exposures before making an

> adjustment). I have tried all the tracking options.

>

> 2) The size of errors being inverse to the focal length have been

> reported by other STV users. The eFinder mode supposedly can track

> to within a 1" accuracy. Some people have been able to use this mode

> with great success.

>

> 3) I am aware of the issues with the STV. It has been driving a lot

> of people crazy (including me). I have a fellow club member who has

> an AP1200 which exhibits spikes although he claims it is in RA not

> Dec.

>

> 4) I have seen problems in images due to the tracking errors. The PE

> image and graph of my mount seems to show some points where there

> are some sharper changes in movement. As I recall the GM-100 was

> rated at about 9" when it first casme out. I have the guide scopes

> mounted on top of the C-8 using a 1/4-20 piggyback mount adapter.

> I have considered possible issues with the mounting of the guide

> scopes, but the precise regularity of the errors seem to point

> elsewhere.



I would *strongly* recommend that you obtain an off axis guider and try

that. Any moving mirror system is prone to exhibit movement that can be

impossible to track down. I wish this wasn't the case. But my success

rate quadrupled once I stared using the OAG. I spent over a year trying

to get my setup dialed in and there are numerous tests that you can run

and I would suggest that you do them. Obtain two reticle EP's and place

them in each optical tube aligned on the same object. Slew 30 degree

away to another bright star. The had better both be dead-on or you have

movement. Slew back and recheck. Are they still dead-on the original

star ????? Probably not :^( This is in my experience a difficult task

and sometimes it is diffult to sort out the details John. But you have

something going for you that I didn't laughs> Someone actually using

GM-100 with very good results (me). Therefore in my naivete I would

suggest that you look elsewhere for your problem(s). And the STV, sadly

enough seems to be a good place to start followed closely by your

Imaging OTA/Guide OTA configuration.



Sure wish you were close by John. It would be easy to isolate your

problem.



Regards



Bill



--

William R. Mattil.| Fred Astaire wasn't so great.

wrmattil@....| Ginger had to do it all backwards

(972) 399-4106..| and... in high heels.







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

#16201 Jul 16, 2003

Hi Bill,



I do have an OAG assembly (Taurus Tracker) which I have used with

mixed results. Near the pole I get great tracking, but further away

is where the tracking degrades. Using the OAG I have found it

difficult at times to find guide stars and keeping the object

properly framed in my imaging CCD using this method. This is why I

was trying the guide scope method. It gives me a lot more

flexibility.

I was able to work with the ST-4, but I ran into the above issue

of framing and getting good focus. I felt the STV would be better

since it was more sensitive and had the display screen so you could

see visually what was happening.

I will give your flexure test a try. I keep wondering what is

causing these spikes to be exactly 4mins apart. I live in the

Chicago area. Not sure where you are.



JohnD



--- In Losmandy_users@yahoogroups.com, "William R. Mattil"

wrmattil@i...> wrote: > j_dwyer99 wrote:

> >

> > Hi guys,

> >

> > Thanks for your responses. I will try to respond to your

comments. > >

> > 1) I have not tried the ST-4 at this point. That is a thought. I

can > > try to contact a club member who has one to see if I can borrow

it > > and see if I get the same results. I actually had one several

years > > ago but did not get much of a chance to use it. I dont recall the

> > tracking accuracy of it. I found it was a little difficult to

use at > > times.

>

> I find this hard to believe John. The ST-4 is a breeze. The first

night > I used it was tracking just fine. But read on. There are some other

> issues/items to consider.

>

> > That is why I went with the STV. I find it is much easier to

> > use as far as finding guide stars and focusing.

>

> This *may* be :^) But FWIW there isn't IMHO a free lunch when it

comes > to Astrophotography. It requires attention to detail.

>

> > It is also great for

> > displaying objects on the video screen at public star parties. It

> > does have more tracking adjustment options available than the ST-

4. > > You have to be certain you enter your guiding scope parameters

for > > it to calibrate and track properly.

>

> Not on the ST-4 .... you must be talking about the STV here. My ST-

4 > works straight up with my GM-100. Assuming appropriate guide star

> paramters of course. If I am taking integrations of less than 1

sec I > will turn on AA (Average Adjust) to average two or three

iterations. The > GM-100 is fine up to 2 sec. The Sa (Scintallation Adjust *must* be

set > on 8 or greater to start. You can lower this once it is assured

that the > seeing is excellent. Not often the case :^(

>

> > In addition to X/Y axis

> > aggessiveness adjustment, it has a "Maximum Correction" option

> > (which limits the amount of any adjustments) and "Exposures to

Avg" > > (which can average a number of exposures before making an

> > adjustment). I have tried all the tracking options.

> >

> > 2) The size of errors being inverse to the focal length have been

> > reported by other STV users. The eFinder mode supposedly can

track > > to within a 1" accuracy. Some people have been able to use this

mode > > with great success.

> >

> > 3) I am aware of the issues with the STV. It has been driving a

lot > > of people crazy (including me). I have a fellow club member who

has > > an AP1200 which exhibits spikes although he claims it is in RA

not > > Dec.

> >

> > 4) I have seen problems in images due to the tracking errors.

The PE > > image and graph of my mount seems to show some points where there

> > are some sharper changes in movement. As I recall the GM-100 was

> > rated at about 9" when it first casme out. I have the guide

scopes > > mounted on top of the C-8 using a 1/4-20 piggyback mount adapter.

> > I have considered possible issues with the mounting of the guide

> > scopes, but the precise regularity of the errors seem to point

> > elsewhere.

>

> I would *strongly* recommend that you obtain an off axis guider

and try > that. Any moving mirror system is prone to exhibit movement that

can be > impossible to track down. I wish this wasn't the case. But my

success > rate quadrupled once I stared using the OAG. I spent over a year

trying > to get my setup dialed in and there are numerous tests that you

can run > and I would suggest that you do them. Obtain two reticle EP's and

place > them in each optical tube aligned on the same object. Slew 30

degree > away to another bright star. The had better both be dead-on or you

have > movement. Slew back and recheck. Are they still dead-on the

original > star ????? Probably not :^( This is in my experience a difficult

task > and sometimes it is diffult to sort out the details John. But you

have > something going for you that I didn't laughs> Someone actually

using > GM-100 with very good results (me). Therefore in my naivete I would

> suggest that you look elsewhere for your problem(s). And the STV,

sadly > enough seems to be a good place to start followed closely by your

> Imaging OTA/Guide OTA configuration.

>

> Sure wish you were close by John. It would be easy to isolate your

> problem.

>

> Regards

>

> Bill

>

> --

> William R. Mattil.| Fred Astaire wasn't so great.

> wrmattil@i....| Ginger had to do it all backwards

> (972) 399-4106..| and... in high heels.







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

#38532 Jul 26, 2008

My large altitude (latitude) adjustment knob came loose and screwed

free. As such I unscrewed it and cleaned the threaded shaft and knob.

However, when I went to put it back on, it wouldn't thread flush with

the mount again and leaves a gap. (See Mount photos in the photo

section.) After closer examination it appears that the threads were

damaged by the set screws used to hold the knob in place on the

threaded shaft. I have used a jewelers file and got them looking

pretty good. However, no matter what I do the knob won't go past a

certain point. When I try to force it past, which I am pretty sure it

would do, it simply starts screwing out the threaded shaft since there

is nothing to keep it from turning. Any suggestions?



Thank you,



Paul Atkinson



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

#38540 Jul 26, 2008

paulatkinson22 wrote: > My large altitude (latitude) adjustment knob came loose and screwed

> free. As such I unscrewed it and cleaned the threaded shaft and knob.

> However, when I went to put it back on, it wouldn't thread flush with

> the mount again and leaves a gap. (See Mount photos in the photo

> section.)



I suggest you take a look at the photos here:

www.astro.uni-bonn.de/~mischa/mounts/g11_disassembly.html>



and maybe also disassemble your mount to discover where it differs.



--

Mike



Mike Dodd

Montpelier, VA USA

astronomy.mdodd.com



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

#53671 Dec 28, 2013

for drift align i use phd with 'disable guide output.' while waiting for the second blown gear i decided to mess with the gear mesh due to the constant lag tracking messages i get on the gemini 2 screen.



ever since i messed with the gear mesh i get the chart below when drift aligning with phd.



i1176.photobucket.com/albums/x328/diurnal1/Untitled_zps9dcf32f6.jpg



when i calibrate on a star it seems to do fine and tracks decent. but i cant drift align anymore. that is just weird that it tracks okay, but when i'm unguided with PHD the red line goes off the chart.



ive checked cables for snags and i used a new rj12 cable hooked in the autoguider and that didn't work. also i been messing with the bearing block spacing. i got it to .863mm for RA and DEC. Is this a correct spacing of the bearing blocks?



the last information i can give you is last night it wouldn't guide right either. the red line on phd went off the chart. here's the last PHD chart and PE chart.

i1176.photobucket.com/albums/x328/diurnal1/calibratedsirius_zpsf0bf8d57.jpg



i1176.photobucket.com/albums/x328/diurnal1/yo_zps48ff5c89.jpg



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

#53672 Dec 28, 2013

--- In Losmandy_users@yahoogroups.com, "Mick" pctradition@...> wrote: >

> for drift align i use phd with 'disable guide output.' while waiting for the second blown gear i decided to mess with the gear mesh due to the constant lag tracking messages i get on the gemini 2 screen.

>

> ever since i messed with the gear mesh i get the chart below when drift aligning with phd.

>

> i1176.photobucket.com/albums/x328/diurnal1/Untitled_zps9dcf32f6.jpg

>

> when i calibrate on a star it seems to do fine and tracks decent. but i cant drift align anymore. that is just weird that it tracks okay, but when i'm unguided with PHD the red line goes off the chart.

>

> ive checked cables for snags and i used a new rj12 cable hooked in the autoguider and that didn't work. also i been messing with the bearing block spacing. i got it to .863mm for RA and DEC. Is this a correct spacing of the bearing blocks?

>

> the last information i can give you is last night it wouldn't guide right either. the red line on phd went off the chart. here's the last PHD chart and PE chart.

> i1176.photobucket.com/albums/x328/diurnal1/calibratedsirius_zpsf0bf8d57.jpg

>

> i1176.photobucket.com/albums/x328/diurnal1/yo_zps48ff5c89.jpg

>





fixed the second link

s1176.photobucket.com/user/diurnal1/media/calibratedsirius_zpsf0bf8d57.jpg.html



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

#53673 Dec 28, 2013

i1176.photobucket.com/albums/x328/diurnal1/calibratedsirius_zpsf0bf8d57.jpg



try again. second link --- In Losmandy_users@yahoogroups.com, "Mick" pctradition@...> wrote:

>

>

>

> --- In Losmandy_users@yahoogroups.com, "Mick" pctradition@> wrote:

> >

> > for drift align i use phd with 'disable guide output.' while waiting for the second blown gear i decided to mess with the gear mesh due to the constant lag tracking messages i get on the gemini 2 screen.

> >

> > ever since i messed with the gear mesh i get the chart below when drift aligning with phd.

> >

> > i1176.photobucket.com/albums/x328/diurnal1/Untitled_zps9dcf32f6.jpg

> >

> > when i calibrate on a star it seems to do fine and tracks decent. but i cant drift align anymore. that is just weird that it tracks okay, but when i'm unguided with PHD the red line goes off the chart.

> >

> > ive checked cables for snags and i used a new rj12 cable hooked in the autoguider and that didn't work. also i been messing with the bearing block spacing. i got it to .863mm for RA and DEC. Is this a correct spacing of the bearing blocks?

> >

> > the last information i can give you is last night it wouldn't guide right either. the red line on phd went off the chart. here's the last PHD chart and PE chart.

> > i1176.photobucket.com/albums/x328/diurnal1/calibratedsirius_zpsf0bf8d57.jpg

> >

> > i1176.photobucket.com/albums/x328/diurnal1/yo_zps48ff5c89.jpg

> >

>

>

> fixed the second link

> s1176.photobucket.com/user/diurnal1/media/calibratedsirius_zpsf0bf8d57.jpg.html

>







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