VintageBigBlue.org

 

Re: ovision vs losmandy graphs


Jun 22, 2008

 


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

#37989 Jun 22, 2008

f1.grp.yahoofs.com/v1/kPVeSIY7eizpE1rmFrrkrc620ZDvDKvrlYQqayANRZZSMNUoKEgI7HA8b42l5JT63K7Uea28d1RSoQdvRGCo/%20Losmandy%20vs.%20Ovision/ovision%20vs%20losmandy%20graph%20and%20pics.jpg>



Hi gang:



The link above is to a graphic compiled by my collaborator Harvey.

These are all 750 second periods. The star trails are pretty easy to

see. The graphs were generated by Harvey using software bisque's

track and accumulate position data to which Harvey then fitted the

graphed curves.



3 to 4 arc seconds is the best way to interpret the results, more

likely a tad under 4 arc seconds peak to peak.



I'm sorry that I have been unable to accommodate requests for better

data, PEMPRO output etc. If you look at the graph there are a couple

of bumps on the Ovision towards the end which may or may not be

something significant: as someone mentioned, several runs are best for

doing this kind of evaluation, and given the difficulties of hauling

this stuff out to Harvey's house it's not likely to happen. Many

people are unaware that to get as far as I did with this project I not

only had to shell out the money, install the worm, and get a volunteer

to help me with the imaging, I also had to haul the G11, marine

battery, telescope, and everything else across nearly one hundred

yards of lawn. I was very interested in the project but I'm not sure

I want to make a habit of this.



I do think the data show that extremely good results are possible with

the Ovision worm and that there is enough there to encourage a few

folks who've been sitting on the sidelines to take the plunge and tell

us how they do.



I think Eric's observation that the Ovision is probably about as good

as it will get with a G11 is basically correct. There may be other

kinds of hardware aftermarket improvements but probably not in the

worm proper. For people interested in squeezing the most out of their

imaging equipment and their mount, it seems to me a very reasonable

investment.



regards

Greg N



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

#37990 Jun 22, 2008

Trying another lnk...



f1.grp.yahoofs.com/v1/oANfSFV9BuQytJx0wBPHSjjOfLjfn8hC6oRfDlHu0Kr\

ZVR0qdT1TNksuHURYLKLRbMTEeE8DU1thcyYmEaDv510IMYKVsjRGoxCA-Q/%20Losmandy%\

20vs.%20Ovision/ovision%20vs%20losmandy%20graph%20and%20pics.jpg

f1.grp.yahoofs.com/v1/oANfSFV9BuQytJx0wBPHSjjOfLjfn8hC6oRfDlHu0K\

rZVR0qdT1TNksuHURYLKLRbMTEeE8DU1thcyYmEaDv510IMYKVsjRGoxCA-Q/%20Losmandy\

%20vs.%20Ovision/ovision%20vs%20losmandy%20graph%20and%20pics.jpg>



Bill











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



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

#37991 Jun 22, 2008

Both links work for me, but links are unstable on Yahoo (I don't know

why) and they probably won't work forever. Interested parties who are

frustrated by the links should navigate to the web site, log in, and

on the left click on FILES



then click on the folder "Losmandy vs. Ovision" and nose around.

There's quite a bit there right now.



regards

Greg N





--- In Losmandy_users@yahoogroups.com, "William J. Shaheen"

wjshaheen@...> wrote: >

>

> Trying another lnk...

>

>

f1.grp.yahoofs.com/v1/oANfSFV9BuQytJx0wBPHSjjOfLjfn8hC6oRfDlHu0Kr\ >

ZVR0qdT1TNksuHURYLKLRbMTEeE8DU1thcyYmEaDv510IMYKVsjRGoxCA-Q/%20Losmandy%\ > 20vs.%20Ovision/ovision%20vs%20losmandy%20graph%20and%20pics.jpg

>

f1.grp.yahoofs.com/v1/oANfSFV9BuQytJx0wBPHSjjOfLjfn8hC6oRfDlHu0K\ >

rZVR0qdT1TNksuHURYLKLRbMTEeE8DU1thcyYmEaDv510IMYKVsjRGoxCA-Q/%20Losmandy\ > %20vs.%20Ovision/ovision%20vs%20losmandy%20graph%20and%20pics.jpg>

>

> Bill

>

>

>

>

>

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

>



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

#37992 Jun 23, 2008

Hi Greg,



The reduction in the amplitude of the error is very obvious: that's

a major improvement in the Ovision worm. What would concern me are

the few cycles where the error is greater and not the same shape as

in the other cycles. This happened at the beginning and then at the

end of the graph. Any idea what was going on there?



I'd love to see measurements from a few more samples of these worms.

An under 4 arcecond PE is an excellent performance, no doubt about

that. But, I also have a Losmandy G11 high-precision worm that

exhibits less than +/-2 arcseconds PE. As we all know, not all

Losmandy worms are that good, so I wonder how consistent the Ovision

worms will prove to be...



Thank you for all your (and Harvey's) hard work on measuring this

new worm! So far it seems like an excellent new option for G11

imagers.



-Paul



--- In Losmandy_users@yahoogroups.com, "gnowellsct" tim71pos@...>

wrote: >

>

f1.grp.yahoofs.com/v1/kPVeSIY7eizpE1rmFrrkrc620ZDvDKvrlYQqayA

NRZZSMNUoKEgI7HA8b42l5JT63K7Uea28d1RSoQdvRGCo/%20Losmandy%20vs.%

20Ovision/ovision%20vs%20losmandy%20graph%20and%20pics.jpg> >

> Hi gang:

>

> The link above is to a graphic compiled by my collaborator Harvey.

> These are all 750 second periods. The star trails are pretty easy

to > see. The graphs were generated by Harvey using software bisque's

> track and accumulate position data to which Harvey then fitted the

> graphed curves.

>

> 3 to 4 arc seconds is the best way to interpret the results, more

> likely a tad under 4 arc seconds peak to peak.

>

> I'm sorry that I have been unable to accommodate requests for

better > data, PEMPRO output etc. If you look at the graph there are a

couple > of bumps on the Ovision towards the end which may or may not be

> something significant: as someone mentioned, several runs are best

for > doing this kind of evaluation, and given the difficulties of

hauling > this stuff out to Harvey's house it's not likely to happen. Many

> people are unaware that to get as far as I did with this project I

not > only had to shell out the money, install the worm, and get a

volunteer > to help me with the imaging, I also had to haul the G11, marine

> battery, telescope, and everything else across nearly one hundred

> yards of lawn. I was very interested in the project but I'm not

sure > I want to make a habit of this.

>

> I do think the data show that extremely good results are possible

with > the Ovision worm and that there is enough there to encourage a few

> folks who've been sitting on the sidelines to take the plunge and

tell > us how they do.

>

> I think Eric's observation that the Ovision is probably about as

good > as it will get with a G11 is basically correct. There may be other

> kinds of hardware aftermarket improvements but probably not in the

> worm proper. For people interested in squeezing the most out of

their > imaging equipment and their mount, it seems to me a very reasonable

> investment.

>

> regards

> Greg N

>







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

#37993 Jun 23, 2008

Given the fact that we only did this run with the scope & ovision worm

I would not put a lot of stock in the graphed information (compared to

the images). There are too many sources of potential error where a

guy calls up an imager and says hey whaddaya say we check this out,

which is my situation. We probably should have done repeated runs but

did not.



I don't know if you missed it but there is an unguided image of M27 in

there (4 x 60 seconds) which shows very good stars and this was

without a careful polar alignment. In fact the polar alignment is

probably the major source of error in the picture (not the native PE).



At this point the door has been opened, which is all I intended to do,

and other people are going to have to supply additional data on the

Ovision retrofit.



To me it seems worth the money because the brass worms will still

leave the problem of incorrect alignment of the bearing blocks.

People who like to mess with exacting adjustments can probably tune

the brass worms to a high degree. But for some ol' joe like me to be

able to slap a worm like this on and get this result for $500 is

indicative that the product performs.



I don't know whether it would affect the result but there may have

been too much backlash in the adjustment I tested. I don't know how

that would affect tracking. I have adjusted almost all the backlash

out now.



And as far as that goes, I can say that this is a much easier

arrangement to adjust. Given the intensity of feelings expressed that

we needed a way to get more performance out of the G11 mount, I think

that this is the ticket for those willing to spend a bit more.



regards

Greg N



--- In Losmandy_users@yahoogroups.com, "Paul K" pkane2001@...> wrote:

>

> Hi Greg,

>

> The reduction in the amplitude of the error is very obvious: that's

> a major improvement in the Ovision worm. What would concern me are

> the few cycles where the error is greater and not the same shape as

> in the other cycles. This happened at the beginning and then at the

> end of the graph. Any idea what was going on there?

>

> I'd love to see measurements from a few more samples of these worms.

> An under 4 arcecond PE is an excellent performance, no doubt about

> that. But, I also have a Losmandy G11 high-precision worm that

> exhibits less than +/-2 arcseconds PE. As we all know, not all

> Losmandy worms are that good, so I wonder how consistent the Ovision

> worms will prove to be...

>

> Thank you for all your (and Harvey's) hard work on measuring this

> new worm! So far it seems like an excellent new option for G11

> imagers.

>

> -Paul

>

> --- In Losmandy_users@yahoogroups.com, "gnowellsct" tim71pos@>

> wrote:

> >

> >

> f1.grp.yahoofs.com/v1/kPVeSIY7eizpE1rmFrrkrc620ZDvDKvrlYQqayA

> NRZZSMNUoKEgI7HA8b42l5JT63K7Uea28d1RSoQdvRGCo/%20Losmandy%20vs.%

> 20Ovision/ovision%20vs%20losmandy%20graph%20and%20pics.jpg>

> >

> > Hi gang:

> >

> > The link above is to a graphic compiled by my collaborator Harvey.

> > These are all 750 second periods. The star trails are pretty easy

> to

> > see. The graphs were generated by Harvey using software bisque's

> > track and accumulate position data to which Harvey then fitted the

> > graphed curves.

> >

> > 3 to 4 arc seconds is the best way to interpret the results, more

> > likely a tad under 4 arc seconds peak to peak.

> >

> > I'm sorry that I have been unable to accommodate requests for

> better

> > data, PEMPRO output etc. If you look at the graph there are a

> couple

> > of bumps on the Ovision towards the end which may or may not be

> > something significant: as someone mentioned, several runs are best

> for

> > doing this kind of evaluation, and given the difficulties of

> hauling

> > this stuff out to Harvey's house it's not likely to happen. Many

> > people are unaware that to get as far as I did with this project I

> not

> > only had to shell out the money, install the worm, and get a

> volunteer

> > to help me with the imaging, I also had to haul the G11, marine

> > battery, telescope, and everything else across nearly one hundred

> > yards of lawn. I was very interested in the project but I'm not

> sure

> > I want to make a habit of this.

> >

> > I do think the data show that extremely good results are possible

> with

> > the Ovision worm and that there is enough there to encourage a few

> > folks who've been sitting on the sidelines to take the plunge and

> tell

> > us how they do.

> >

> > I think Eric's observation that the Ovision is probably about as

> good

> > as it will get with a G11 is basically correct. There may be other

> > kinds of hardware aftermarket improvements but probably not in the

> > worm proper. For people interested in squeezing the most out of

> their

> > imaging equipment and their mount, it seems to me a very reasonable

> > investment.

> >

> > regards

> > Greg N

> >

>







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

#37995 Jun 23, 2008

Greg, it's very hard to judge PE from an image, especially one

that's a processed JPEG. Autoguider log data provides much more

information and is much more reliable. For example, here's a single

5 minute unguided image of M101 I took a few years back:



pk.darkhorizons.org/m101-unguided-5min.jpg



Can you tell what the PE was during this shot? I can't, although it

seems low g>



Lots of backlash could certainly account for the variation in error,

especially if the mount was well-balanced in RA (not heavier to one

side).



Ovision worm seems to indeed provide an excellent value, but I'd

advise a bit of caution until there are more samples to confirm this

level of performance.



Regards,



-Paul



--- In Losmandy_users@yahoogroups.com, "gnowellsct" tim71pos@...>

wrote: >

> Given the fact that we only did this run with the scope & ovision

worm > I would not put a lot of stock in the graphed information

(compared to > the images). There are too many sources of potential error where a

> guy calls up an imager and says hey whaddaya say we check this out,

> which is my situation. We probably should have done repeated runs

but > did not.

>

> I don't know if you missed it but there is an unguided image of

M27 in > there (4 x 60 seconds) which shows very good stars and this was

> without a careful polar alignment. In fact the polar alignment is

> probably the major source of error in the picture (not the native

PE). >

> At this point the door has been opened, which is all I intended to

do, > and other people are going to have to supply additional data on the

> Ovision retrofit.

>

> To me it seems worth the money because the brass worms will still

> leave the problem of incorrect alignment of the bearing blocks.

> People who like to mess with exacting adjustments can probably tune

> the brass worms to a high degree. But for some ol' joe like me to

be > able to slap a worm like this on and get this result for $500 is

> indicative that the product performs.

>

> I don't know whether it would affect the result but there may have

> been too much backlash in the adjustment I tested. I don't know how

> that would affect tracking. I have adjusted almost all the

backlash > out now.

>

> And as far as that goes, I can say that this is a much easier

> arrangement to adjust. Given the intensity of feelings expressed

that > we needed a way to get more performance out of the G11 mount, I

think > that this is the ticket for those willing to spend a bit more.

>

> regards

> Greg N

>

>

> --- In Losmandy_users@yahoogroups.com, "Paul K" pkane2001@> wrote:

> >

> > Hi Greg,

> >

> > The reduction in the amplitude of the error is very obvious:

that's > > a major improvement in the Ovision worm. What would concern me

are > > the few cycles where the error is greater and not the same shape

as > > in the other cycles. This happened at the beginning and then at

the > > end of the graph. Any idea what was going on there?

> >

> > I'd love to see measurements from a few more samples of these

worms. > > An under 4 arcecond PE is an excellent performance, no doubt

about > > that. But, I also have a Losmandy G11 high-precision worm that

> > exhibits less than +/-2 arcseconds PE. As we all know, not all

> > Losmandy worms are that good, so I wonder how consistent the

Ovision > > worms will prove to be...

> >

> > Thank you for all your (and Harvey's) hard work on measuring

this > > new worm! So far it seems like an excellent new option for G11

> > imagers.

> >

> > -Paul

> >

> > --- In Losmandy_users@yahoogroups.com, "gnowellsct" tim71pos@>

> > wrote:

> > >

> > >

> >

f1.grp.yahoofs.com/v1/kPVeSIY7eizpE1rmFrrkrc620ZDvDKvrlYQqayA > > NRZZSMNUoKEgI7HA8b42l5JT63K7Uea28d1RSoQdvRGCo/%20Losmandy%20vs.%

> > 20Ovision/ovision%20vs%20losmandy%20graph%20and%20pics.jpg>

> > >

> > > Hi gang:

> > >

> > > The link above is to a graphic compiled by my collaborator

Harvey. > > > These are all 750 second periods. The star trails are pretty

easy > > to

> > > see. The graphs were generated by Harvey using software

bisque's > > > track and accumulate position data to which Harvey then fitted

the > > > graphed curves.

> > >

> > > 3 to 4 arc seconds is the best way to interpret the results,

more > > > likely a tad under 4 arc seconds peak to peak.

> > >

> > > I'm sorry that I have been unable to accommodate requests for

> > better

> > > data, PEMPRO output etc. If you look at the graph there are a

> > couple

> > > of bumps on the Ovision towards the end which may or may not be

> > > something significant: as someone mentioned, several runs are

best > > for

> > > doing this kind of evaluation, and given the difficulties of

> > hauling

> > > this stuff out to Harvey's house it's not likely to happen.

Many > > > people are unaware that to get as far as I did with this

project I > > not

> > > only had to shell out the money, install the worm, and get a

> > volunteer

> > > to help me with the imaging, I also had to haul the G11, marine

> > > battery, telescope, and everything else across nearly one

hundred > > > yards of lawn. I was very interested in the project but I'm

not > > sure

> > > I want to make a habit of this.

> > >

> > > I do think the data show that extremely good results are

possible > > with

> > > the Ovision worm and that there is enough there to encourage a

few > > > folks who've been sitting on the sidelines to take the plunge

and > > tell

> > > us how they do.

> > >

> > > I think Eric's observation that the Ovision is probably about

as > > good

> > > as it will get with a G11 is basically correct. There may be

other > > > kinds of hardware aftermarket improvements but probably not in

the > > > worm proper. For people interested in squeezing the most out

of > > their

> > > imaging equipment and their mount, it seems to me a very

reasonable > > > investment.

> > >

> > > regards

> > > Greg N

> > >

> >

>







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

#37996 Jun 23, 2008

Hi Greg,



I'm sure everyone here is grateful to you and to Ovision for your

time and testing. It's great to see that there are efforts being made

to improve this otherwise great mount. Now, only if Scott would take

these same measures! :)



While the PE curve shows error on the order of roughly +/- 1.5 arc

seconds (3 arcseconds total error), the actual point data suggests

that it's more like +/- 3.5 (7 arcseconds total error). That seems to

be in line with what a lot of stock G11 users are getting (just

speaking anecdotally). So it appears that the big advantage of the

Ovision is the ability to get rid of the bearing blocks -- those

annoying cubes that are the bane of all who try to image with this

mount (I actually have the GM-8 but same issue).



I have a new brass worm for my GM-8, which I have yet to install.

I'll be very interested in seeing if it brings my PE down from about

12 arcseconds (total). Even if it doesn't, the steel worm I currently

have has smooth PE, which is easy to guide out. I'd expect at least

the same performance but, of course, I'm hoping for better. I'll be

sure to post results of that mod.



What I would really LOVE to see (Scott, are you listening? :), is the

height of the DEC assembly reduced bringing it closer to the RA

assembly, reworking of the motor/encoder/reduction gear/worm

assemblies such that they are stacked rather than in line with each

other (making them way too long and protruding out to the side of the

mount), and through-the-mount cabling. But that last one is just

a "nice to have". Until then, it's good that we have modification

options out there.



Best, and thanks again for your work.



Danny

www.californiastars.net/







--- In Losmandy_users@yahoogroups.com, "gnowellsct" tim71pos@...>

wrote: >

>

f1.grp.yahoofs.com/v1/kPVeSIY7eizpE1rmFrrkrc620ZDvDKvrlYQqayAN

RZZSMNUoKEgI7HA8b42l5JT63K7Uea28d1RSoQdvRGCo/%20Losmandy%20vs.%

20Ovision/ovision%20vs%20losmandy%20graph%20and%20pics.jpg> >

> Hi gang:

>

> The link above is to a graphic compiled by my collaborator Harvey.

> These are all 750 second periods. The star trails are pretty easy

to > see. The graphs were generated by Harvey using software bisque's

> track and accumulate position data to which Harvey then fitted the

> graphed curves.

>

> 3 to 4 arc seconds is the best way to interpret the results, more

> likely a tad under 4 arc seconds peak to peak.

>

> I'm sorry that I have been unable to accommodate requests for better

> data, PEMPRO output etc. If you look at the graph there are a couple

> of bumps on the Ovision towards the end which may or may not be

> something significant: as someone mentioned, several runs are best

for > doing this kind of evaluation, and given the difficulties of hauling

> this stuff out to Harvey's house it's not likely to happen. Many

> people are unaware that to get as far as I did with this project I

not > only had to shell out the money, install the worm, and get a

volunteer > to help me with the imaging, I also had to haul the G11, marine

> battery, telescope, and everything else across nearly one hundred

> yards of lawn. I was very interested in the project but I'm not

sure > I want to make a habit of this.

>

> I do think the data show that extremely good results are possible

with > the Ovision worm and that there is enough there to encourage a few

> folks who've been sitting on the sidelines to take the plunge and

tell > us how they do.

>

> I think Eric's observation that the Ovision is probably about as

good > as it will get with a G11 is basically correct. There may be other

> kinds of hardware aftermarket improvements but probably not in the

> worm proper. For people interested in squeezing the most out of

their > imaging equipment and their mount, it seems to me a very reasonable

> investment.

>

> regards

> Greg N

>



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

#37997 Jun 23, 2008

Indeed. But there's enough there to convince all but the most hardy

souls that the water is warm, if not perhaps as warm as they might

like. If everyone is too cautious there won't be additional data.



The mount was in fact "perfectly balanced" rather than offset and that

may have affected the two last humps in the graphed data, since the

backlash was also large.



I would be surprised if any but the most carefully shimmed default

G11s were doing as well. When I removed the old bearing blocks I was

astounded at the amount of play between the bearing and the bearing

block.



Anyhow that's about it. I think Ovision is delivering what they

promised at a very good price. I'm not certain that, if you stay

within the load capacity, that there is even a lot to be gained in PE

control by moving to something like the AP mach 1. Maybe as Eric said

it has better control of other slight noise items like in the gears.

In some ways you might be better off with the Gemini/G11, however,

particularly in the paddle, whose programmed capabilities are better

than the current versions of the AP and Tak paddles.



regards

Greg N

--- In Losmandy_users@yahoogroups.com, "Paul K" pkane2001@...> wrote:



> Ovision worm seems to indeed provide an excellent value, but I'd

> advise a bit of caution until there are more samples to confirm this

> level of performance.

>

> Regards,

>

> -Paul

>

>







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

#38000 Jun 23, 2008

Thanks Greg for testing the Ovision worm assembly. I'm convinced that

elimination of the bearing blocks alignment issue coupled with the

precision worm makes this a good choice for my G11. Considering the

cost of machining and time and expertise to manufacture, it is worth

the money (especially considering the prices of AP or Tak mounts with

similar capacity). Much appreciated.



Best regards....Carl



--- In Losmandy_users@yahoogroups.com, "gnowellsct" tim71pos@...>

wrote: >

> Indeed. But there's enough there to convince all but the most hardy

> souls that the water is warm, if not perhaps as warm as they might

> like. If everyone is too cautious there won't be additional data.

>

> The mount was in fact "perfectly balanced" rather than offset and

that > may have affected the two last humps in the graphed data, since the

> backlash was also large.

>

> I would be surprised if any but the most carefully shimmed default

> G11s were doing as well. When I removed the old bearing blocks I

was > astounded at the amount of play between the bearing and the bearing

> block.

>

> Anyhow that's about it. I think Ovision is delivering what they

> promised at a very good price. I'm not certain that, if you stay

> within the load capacity, that there is even a lot to be gained in

PE > control by moving to something like the AP mach 1. Maybe as Eric

said > it has better control of other slight noise items like in the

gears. > In some ways you might be better off with the Gemini/G11, however,

> particularly in the paddle, whose programmed capabilities are better

> than the current versions of the AP and Tak paddles.

>

> regards

> Greg N

>

> --- In Losmandy_users@yahoogroups.com, "Paul K" pkane2001@> wrote:

>

> > Ovision worm seems to indeed provide an excellent value, but I'd

> > advise a bit of caution until there are more samples to confirm

this > > level of performance.

> >

> > Regards,

> >

> > -Paul

> >

> >

>



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

#38004 Jun 23, 2008

Well I'm looking forward to additional reports from folks who can do

more thorough testing than myself. Please do take the time to share

your results! regards Greg N



--- In Losmandy_users@yahoogroups.com, "Carl Novosel" icee_stars@...>

wrote: >

> Thanks Greg for testing the Ovision worm assembly. I'm convinced that

> elimination of the bearing blocks alignment issue coupled with the

> precision worm makes this a good choice for my G11. Considering the

> cost of machining and time and expertise to manufacture, it is worth

> the money (especially considering the prices of AP or Tak mounts with

> similar capacity). Much appreciated.

>

> Best regards....Carl

>

> --- In Losmandy_users@yahoogroups.com, "gnowellsct" tim71pos@>

> wrote:

> >

> > Indeed. But there's enough there to convince all but the most hardy

> > souls that the water is warm, if not perhaps as warm as they might

> > like. If everyone is too cautious there won't be additional data.

> >

> > The mount was in fact "perfectly balanced" rather than offset and

> that

> > may have affected the two last humps in the graphed data, since the

> > backlash was also large.

> >

> > I would be surprised if any but the most carefully shimmed default

> > G11s were doing as well. When I removed the old bearing blocks I

> was

> > astounded at the amount of play between the bearing and the bearing

> > block.

> >

> > Anyhow that's about it. I think Ovision is delivering what they

> > promised at a very good price. I'm not certain that, if you stay

> > within the load capacity, that there is even a lot to be gained in

> PE

> > control by moving to something like the AP mach 1. Maybe as Eric

> said

> > it has better control of other slight noise items like in the

> gears.

> > In some ways you might be better off with the Gemini/G11, however,

> > particularly in the paddle, whose programmed capabilities are better

> > than the current versions of the AP and Tak paddles.

> >

> > regards

> > Greg N

> >

> > --- In Losmandy_users@yahoogroups.com, "Paul K" pkane2001@> wrote:

> >

> > > Ovision worm seems to indeed provide an excellent value, but I'd

> > > advise a bit of caution until there are more samples to confirm

> this

> > > level of performance.

> > >

> > > Regards,

> > >

> > > -Paul

> > >

> > >

> >

>



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

#38027 Jun 27, 2008

All,



Somewhere I missed this in these threads and I can't seem to sort it

out from Ovision's website: is the EUR368 price for the G-11 worm for

two worms or one?



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

#38029 Jun 27, 2008

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

> All,

>

> Somewhere I missed this in these threads and I can't seem to sort it

> out from Ovision's website: is the EUR368 price for the G-11 worm for

> two worms or one?

>

Hi,



It's for one worm.



Regards



Claudio







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

#38031 Jun 27, 2008

Thanks, Claudio.



--- In Losmandy_users@yahoogroups.com, "schinazic"

claudio.schinazi@...> wrote: >

> --- In Losmandy_users@yahoogroups.com, "macdonjh" macdonjh@>

wrote: > >

> > All,

> >

> > Somewhere I missed this in these threads and I can't seem to

sort it > > out from Ovision's website: is the EUR368 price for the G-11

worm for > > two worms or one?

> >

> Hi,

>

> It's for one worm.

>

> Regards

>

> Claudio

>



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

#38043 Jun 28, 2008

One worm. Not clear why you would want both. regards Greg N

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

>

> All,

>

> Somewhere I missed this in these threads and I can't seem to sort it

> out from Ovision's website: is the EUR368 price for the G-11 worm for

> two worms or one?

>



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

#38044 Jun 28, 2008

And the U.S. price has been set for now at $500, regardless of

exchange rate, which works out less than the Euro price.



regards

Greg N





--- In Losmandy_users@yahoogroups.com, "schinazic"

claudio.schinazi@...> wrote: >

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

> >

> > All,

> >

> > Somewhere I missed this in these threads and I can't seem to sort it

> > out from Ovision's website: is the EUR368 price for the G-11 worm for

> > two worms or one?

> >

> Hi,

>

> It's for one worm.

>

> Regards

>

> Claudio

>



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

#38046 Jun 28, 2008

gnowellsct wrote: > I should mention I'm a little suspicious of the data in my own

> article. The reason is, as I mentioned, that I had the backlash set

> much looser than it should have been.



I wouldn't think backlash would have much effect on PE measurements,

since the worm is _always_ pushing against the worm gear (assuming an

east-heavy counterweight bias). As we know, PEMpro measures PE while the

scope is tracking unguided. But even if the PE is measured by some other

method, using an autoguider log, eastward corrections never cause the RA

motor to reverse direction, so again backlash is not an issue.



Mike

-----



Mike Dodd

Montpelier, VA USA

astronomy.mdodd.com



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