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  #21  
Old 07-11-2009, 09:56 PM
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kinetic (Steve)
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Stuart,

what was the declination of your test star out of interest?

Steve
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  #22  
Old 07-11-2009, 10:16 PM
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Zero(ish)
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  #23  
Old 07-11-2009, 10:37 PM
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Bassnut (Fred)
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4 arcsecs P/P and 1.11 RMS is excellent (with 3arcsecs seeing?, I dont quite get that). Anyway, thats near to PME type results, couldnt get better than that, nice work
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  #24  
Old 08-11-2009, 09:09 AM
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Quote:
Originally Posted by Bassnut View Post
4 arcsecs P/P and 1.11 RMS is excellent (with 3arcsecs seeing?, I dont quite get that). Anyway, thats near to PME type results, couldnt get better than that, nice work
The way I look at the figures, the underlying PE is 4" P/P, then add on 3" for seeing, so over the 20 minutes I was taking data I should get about 7" P/P. Each individual worm run may be less.

So the data shows the mount to be tracking well doe sit Fred? I have no experience with this, so shoot me some figures.

The other reports on the Ovision also state things like "PME performance", also comparing the mount to APs in the PE.

It was a bit cloudy at sunset last night, but cleared up later. I had been working around the house all day and was a bit stuffed, so didn't setup. Should have, I went out at around midnight, clearest skies I've seen in a while. Try tonight maybe.

Cheers
Stuart
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  #25  
Old 08-11-2009, 11:33 AM
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Bassnut (Fred)
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Staurt

The 1st curve with original worms is 25 pixels p/p*.8=20 arcs/secs. Thats awefull, and worse, not regular for each pass (not just the 76 sec problem, generally rough) its impossible to get a pec curve with that, there is no periodic data there to average out.

I had somewhat better curves, without the 76 problem (or small), of about 7-8 arcsecs P/P. So I gave up generating a pec curve and found guideing without pec gave me a slightly lower p/p, but RMS of between 1 and 2 because the error, although not that periodic, was smooth enough to guide out at 2 sec guide exposures.

I found, as some others have, that error (periodic and not) actually smooths out a bit with the G11 slightly overloaded, so I was lucky and got away with no pec.

The Ovision worm graph shows a p/p of what, 4-5 arcsecs (ignor the fact its pushed up the scale, the 1 st blue line did that, you know all this, Im just rabbiting on ;-), periodic and very smooth, in fact I dont think ive seen a G11 raw PE curve this small and smooth, and with 3 arcsec seeing, a fair amount of that would be seeing (what were the exposure times, that makes a big difference).

The raw, out of the box PE of a PME is about 5 arcsecs P/P, and 1-2 RMS, although with PEC, P/P gets to 2 or so and RMS less than 1. Its a bit hard to tell exactly what it is, seeing makes a big difference, as I suspect would be with your curves.

If you expand a raw Ovision curve and compare it with the final curve with PEC, they look the same!. I maybe wrong, but I dont think PEC is on, or its not working (or the "raw" graph has PEC on). The final curves still show the same PE on each pass, which should cancel out with PEC.

If thats the case, and you can correct out the PE showing on the final graph, then your G11 will be well tuned indeed ;-)
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  #26  
Old 09-11-2009, 12:51 AM
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Here's the result.

Quick and dirty processing, please excuse.

NGC 210.

10 x 10 minute Luminance frames, guided on the internal guide chip using the AOL.

CCDStack reports FWHM of 4 (must be pixels as it has no idea of the image scale), so that's 3.5".

Cheers
Stuart
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  #27  
Old 09-11-2009, 08:58 AM
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multiweb (Marc)
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The RMS is a good indication of how tight your guiding is when you stack in the CCDIS popup window. From the stars on your pic it looks great already. Nice and round.
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  #28  
Old 09-11-2009, 10:50 AM
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Looks good Staurt, seems the upgrade was well worth it.
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  #29  
Old 09-11-2009, 11:01 AM
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I am looking to pick up a G11 next month so how easy is the ovision mod. I have no skills in using hammers, screwdrivers or any tools.

Frank
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  #30  
Old 09-11-2009, 12:25 PM
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Originally Posted by telecasterguru View Post
I am looking to pick up a G11 next month so how easy is the ovision mod. I have no skills in using hammers, screwdrivers or any tools.

Frank
You'll just need two allen keys. It's a straight swap.
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  #31  
Old 09-11-2009, 01:02 PM
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what payment method did you use and are they easy to contact.
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  #32  
Old 09-11-2009, 01:20 PM
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telecasterguru (Frank)
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Even though it only takes 2 allen keys to fit, is there any fiddling around to get it to work perfectly or is it perfect out of the box?

Frank
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  #33  
Old 09-11-2009, 01:40 PM
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wasyoungonce (Brendan)
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Here's the result.
A very nice upgrade indeed. Thanks for the info.
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  #34  
Old 09-11-2009, 01:54 PM
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Quote:
Originally Posted by telecasterguru View Post
Even though it only takes 2 allen keys to fit, is there any fiddling around to get it to work perfectly or is it perfect out of the box?

Frank
Just standard meshing. The only difference is that it's just one block instead of two end blocks. The nipple on the motor side is tight so it only rotates,on the other side the hole is slightly bigger so you can adjust your meshing. There's heaps of tutorials online to google on how to remove or set your G11 worms.
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  #35  
Old 09-11-2009, 02:55 PM
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Quote:
Originally Posted by mick pinner View Post
what payment method did you use and are they easy to contact.
Hi Mick,

Paid with credit card, just fill out the order for non-EU countries from their website and send it to them by email. It took a couple of weeks from memory.

Cheers
Stuart
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  #36  
Old 09-11-2009, 11:20 PM
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Quote:
Originally Posted by Bassnut View Post
Staurt
If you expand a raw Ovision curve and compare it with the final curve with PEC, they look the same!. I maybe wrong, but I dont think PEC is on, or its not working (or the "raw" graph has PEC on). The final curves still show the same PE on each pass, which should cancel out with PEC.
Now this got me thinking...

What I believe was happening was that the PE was in fact increasing. I inverted the curve and sent it back to the G11.

What a difference! I'll upload the data when I get it from the obs PC. I reckon +/-2" from the P-P data, so averaged out that should be about 2" PE.

WooHoo!!

I might even try an unguided exposure...

Cheers
Stuart
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  #37  
Old 09-11-2009, 11:41 PM
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I have had mine for quite some time now, but just have not had the time to install and test it out. We ordered three of them near the start of the year, and so far only Kal has had his installed. I still have mine in its box.

One concern i have had but i wanted to try it before sending it back. Is that I noticed when manually turning it very slowly i can notice for lack of a better word "bumps". Apoman has alse noted this on his and is hestant to install it. But turning it fast it seems very smooth.

Sturart did you notice this on yours?
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  #38  
Old 10-11-2009, 12:03 AM
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Quote:
Originally Posted by netwolf View Post
I have had mine for quite some time now, but just have not had the time to install and test it out. We ordered three of them near the start of the year, and so far only Kal has had his installed. I still have mine in its box.

One concern i have had but i wanted to try it before sending it back. Is that I noticed when manually turning it very slowly i can notice for lack of a better word "bumps". Apoman has alse noted this on his and is hestant to install it. But turning it fast it seems very smooth.

Sturart did you notice this on yours?
Nope, smooth as silk. They are tested before they leave, install it, you won't regret it.

Cheers
Stuart
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  #39  
Old 11-11-2009, 01:13 AM
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You would think Scott Losmandy would have attended to this problem by now
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  #40  
Old 11-11-2009, 07:38 AM
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He may have, I bought the mount secondhand from here, so I don't know the age.

The Ovision worm works in two ways, the mounting removes the 76 second error, but the worm is a really high precision part.

Cheers
Stuart
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