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Re: Ovision worm - verdict?


Jul 28, 2009

 


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#43492 Jul 28, 2009

Is there a definitive verdict on the effectivess of the Ovision worm? Does it provide $500 worth of improvement over the Losmandy HP worm?



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#43494 Jul 28, 2009

Not sure there is a definitive conclusion reached on this as yet. I just bought PemPro and will be running it to try to get a real PE from the run. I have tried other things like guiding with the corrections disabled in PHD and then checking the resulting log with PECPrep and it seems to show less than 2" at this time, but I have another that shows about 3.5-4" PE.

I can say that it does seem to have smoothed things a lot.

Floyd --- In Losmandy_users@yahoogroups.com, "Curtis Croulet" calypte@...> wrote:

>

> Is there a definitive verdict on the effectivess of the Ovision worm? Does it provide $500 worth of improvement over the Losmandy HP worm?

>



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

#43496 Jul 28, 2009

I can only speak of my experience........................



Prior to Ovision installation it was impossible to image with my G11 and

my LX200R 10" (focal length with f6.3 reducer/flattener ~ 1800mm).

Periodic Error was simply to sharp to guide out

at this focal length.



I am now imaging consistently with this set-up and getting round stars.

I do have to use my dual chip SBIG or my OAG/DSLR combo due to mirror shift.



I recently imaged at 320mm with my Stellarview SV80S. I rough polar

aligned and went at it. The stars were perfect (I admit to working hard

to remove most DEC back-lash).\



I ran PemPro after installing the Ovision worm and got a total of 2.29

arc seconds P to P. I'm not sure I believe that result but it must be

pretty good.





I can say I am completely satisfied I got my $500.00 worth................







There is no doubt it does improve the G11............... How much it

improves it is an on-going debate. I feel it was the single best thing I

spent my money on that gave me a noticeable "edge"

with my Astrophotography.











Curtis Croulet wrote: > Is there a definitive verdict on the effectivess of the Ovision worm? Does it provide $500 worth of improvement over the Losmandy HP worm?

>

>

>

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

>

> Yahoo! Groups Links

>

>

>

>

>



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#43497 Jul 28, 2009

--- In Losmandy_users@yahoogroups.com, Steve Izzo sdizzo@...> wrote: >

> I can only speak of my experience........................

>

> Prior to Ovision installation it was impossible to image with my G11 and

> my LX200R 10" (focal length with f6.3 reducer/flattener ~ 1800mm).

> Periodic Error was simply to sharp to guide out

> at this focal length.



My question is occasioned by a shooting session last night (July 27-28, '09) where I was shooting in the southern sky with my TV-85 and reducer, which gives an FL of 480 mm. It's not a demanding set-up, and some people may be satisfied with the star images I got, as indeed I was two years ago. Bright stars are fine, but faint stars are noticeable ovals when I enlarge the images, and, watching the tracking display in CCDSoft, I could see that the PE was rather extreme at times and much greater than dec errors. I had polar alignment pretty much nailed. At such times, one starts thinking of alternatives, and an Ovision worm is cheaper than an A-P mount g>.



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#43501 Jul 28, 2009

We've seen results posted here that are all "within spec" from Ovision. Bearing in mind that Ovision doesn't make the whole mount, we would expect some variation: first, because even Ovision doesn't make completely identical units, and second, because there are factors that Ovision doesn't control, such as the accuracy of the teeth on the worm wheel of the mount itself.



All considered, the results seem to be anywhere from 2 to 8 arc seconds peak to peak: but what has most people pleased is that the PE is very smooth and regular, so it is easy to guide out errors. There are people in the 5-7 arc second category who are happy because their autoguiders can now "handle" what the mount gives them.



regards

Greg N







--- In Losmandy_users@yahoogroups.com, Steve Izzo sdizzo@...> wrote:

>

> I can only speak of my experience........................

>

> Prior to Ovision installation it was impossible to image with my G11 and

> my LX200R 10" (focal length with f6.3 reducer/flattener ~ 1800mm).

> Periodic Error was simply to sharp to guide out

> at this focal length.

>

> I am now imaging consistently with this set-up and getting round stars.

> I do have to use my dual chip SBIG or my OAG/DSLR combo due to mirror shift.

>

> I recently imaged at 320mm with my Stellarview SV80S. I rough polar

> aligned and went at it. The stars were perfect (I admit to working hard

> to remove most DEC back-lash).\

>

> I ran PemPro after installing the Ovision worm and got a total of 2.29

> arc seconds P to P. I'm not sure I believe that result but it must be

> pretty good.

>

>

> I can say I am completely satisfied I got my $500.00 worth................

>

>

>

> There is no doubt it does improve the G11............... How much it

> improves it is an on-going debate. I feel it was the single best thing I

> spent my money on that gave me a noticeable "edge"

> with my Astrophotography.

>

>

>

>

>

> Curtis Croulet wrote:

> > Is there a definitive verdict on the effectivess of the Ovision worm? Does it provide $500 worth of improvement over the Losmandy HP worm?

> >

> >

> >

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

> >

> > Yahoo! Groups Links

> >

> >

> >

> >

> >

>







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

#43506 Jul 29, 2009

I bought my Ovision worm last October for my G-11, and I can now consistently guide better than 1 arcsec, and sometimes as low as 0.3 arcsec RMS. I image at 2350mm.



I'm very glad I upgraded to it.



-Joe



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

#43511 Jul 29, 2009

Hi,

Just so happens that I did take a one hour exposure with no guiding and the Polar Alignment intensionally set wrong, so that I would get good trails.



I uploaded these to this folder.

groups.yahoo.com/group/Losmandy_users/photos/album/1307745612/pic/list



They are the last two pictures. One shows the one hour exposure, image scale is 1.17" and the other shows a crop of 1 worm period, 240 secs, with a 1 pixel line drawn through the center of the wave form. This allows you to see how many pixels the star moved up and down. You can see that the bight pixels, the centroid of the star moved about one pixel up and 3 down (approximately) peak to peak or about 5". The trails and the stars were difficult read with certainty, it seems like the centroid moved as I described, but hard to be sure.

The quality of the crop is not so great because I had to blow it up so you could see it well as it was only about a 1 inch section of one star trail representing 240 secs of time.



I also did a non guided log that night that showed these measurements that was 2 worm periods. This seems to show about 2.67" peak to peak. Not sure which is correct.

This of course shows the PE as seen by PHD with guiding corrections disabled.



Peak PE+:.1.67 arcsecs

Peak PE-:.-1.00 arcsecs

RMS PE: ..0.54 arcsecs

Av. PE: ..-0.19 arcsecs

Av. PE+:..0.41 arcsecs

Av. PE-:..-0.43 arcsecs

Max Delta+:.0.37 arcsecs

Max Delta-:.-0.32 arcsecs

Av. Noise:.0.02 arcsecs



Hope this information is what you wanted.

Floyd

--- In Losmandy_users@yahoogroups.com, "photons" photons0@...> wrote:

>

> hia! Floyd... sure would be nice to have a visual of that ovision worms PE..

>

> software graph/analysis is great, dont get me wrong! but a visual star trail of the PE is priceless.. :) youll know for certain you have PEC trained just right if you do the test.

>

>

>

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

> >

> > Not sure there is a definitive conclusion reached on this as yet. I just bought PemPro and will be running it to try to get a real PE from the run. I have tried other things like guiding with the corrections disabled in PHD and then checking the resulting log with PECPrep and it seems to show less than 2" at this time, but I have another that shows about 3.5-4" PE.

> > I can say that it does seem to have smoothed things a lot.

> > Floyd

> > --- In Losmandy_users@yahoogroups.com, "Curtis Croulet" calypte@> wrote:

> > >

> > > Is there a definitive verdict on the effectivess of the Ovision worm? Does it provide $500 worth of improvement over the Losmandy HP worm?

> > >

> >

>



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

#43514 Jul 29, 2009

very nice Floyd... thanks for going through the trouble.. it shows you have a smooth worm in that area of the gear... i plan on checking mine from horizon to horizon just for the hell of it.. and where there's bumps if any im gonna mark that area and inspect the gear wheel closely if i cant fix it i can avoid it at least.



robert

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

>

> Hi,

> Just so happens that I did take a one hour exposure with no guiding and the Polar Alignment intensionally set wrong, so that I would get good trails.

>

> I uploaded these to this folder.

> groups.yahoo.com/group/Losmandy_users/photos/album/1307745612/pic/list

>

> They are the last two pictures. One shows the one hour exposure, image scale is 1.17" and the other shows a crop of 1 worm period, 240 secs, with a 1 pixel line drawn through the center of the wave form. This allows you to see how many pixels the star moved up and down. You can see that the bight pixels, the centroid of the star moved about one pixel up and 3 down (approximately) peak to peak or about 5". The trails and the stars were difficult read with certainty, it seems like the centroid moved as I described, but hard to be sure.

> The quality of the crop is not so great because I had to blow it up so you could see it well as it was only about a 1 inch section of one star trail representing 240 secs of time.

>

> I also did a non guided log that night that showed these measurements that was 2 worm periods. This seems to show about 2.67" peak to peak. Not sure which is correct.

> This of course shows the PE as seen by PHD with guiding corrections disabled.

>

> Peak PE+:.1.67 arcsecs

> Peak PE-:.-1.00 arcsecs

> RMS PE: ..0.54 arcsecs

> Av. PE: ..-0.19 arcsecs

> Av. PE+:..0.41 arcsecs

> Av. PE-:..-0.43 arcsecs

> Max Delta+:.0.37 arcsecs

> Max Delta-:.-0.32 arcsecs

> Av. Noise:.0.02 arcsecs

>

> Hope this information is what you wanted.

> Floyd

>

> --- In Losmandy_users@yahoogroups.com, "photons" photons0@> wrote:

> >

> > hia! Floyd... sure would be nice to have a visual of that ovision worms PE..

> >

> > software graph/analysis is great, dont get me wrong! but a visual star trail of the PE is priceless.. :) youll know for certain you have PEC trained just right if you do the test.

> >

> >

> >

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

> > >

> > > Not sure there is a definitive conclusion reached on this as yet. I just bought PemPro and will be running it to try to get a real PE from the run. I have tried other things like guiding with the corrections disabled in PHD and then checking the resulting log with PECPrep and it seems to show less than 2" at this time, but I have another that shows about 3.5-4" PE.

> > > I can say that it does seem to have smoothed things a lot.

> > > Floyd

> > > --- In Losmandy_users@yahoogroups.com, "Curtis Croulet" calypte@> wrote:

> > > >

> > > > Is there a definitive verdict on the effectivess of the Ovision worm? Does it provide $500 worth of improvement over the Losmandy HP worm?

> > > >

> > >

> >

>







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

#43517 Jul 29, 2009

--- In Losmandy_users@yahoogroups.com, "Joe Ulowetz" joe.ulowetz@...> wrote: >

> I bought my Ovision worm last October for my G-11, and I can now consistently guide better than 1 arcsec, and sometimes as low as 0.3 arcsec RMS. I image at 2350mm.

>

> I'm very glad I upgraded to it.

>

> -Joe

>



That's a strong endorsement of the Ovision worm. Thanks.



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