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Polishing a Worm!

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#26 orlyandico


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Posted 21 December 2012 - 10:53 AM

Probably if you have a matched Aeroquest worm and ring gear, 5" p-p might be possible. But in my case I only have the worm.

Based on my measurements, my Aeroquest worm is really +/- 8.

this is based on isolating the fundamental on the CGEM. the 8/3 is actually much worse (about 20" p-p). Total system PE is about 40" p-p.

to be honest i don't think the Aeroquest would be +/- 2.5" - that would make them better than the Ovision and even better than the native PE of the Mach1 or AP900... which seems to stretch credulity a bit much. I'm not trashing the Aeroquest - it's $100 after all. Just being realistic.

#27 neilson


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Posted 21 December 2012 - 11:27 AM

Thank you Blueman and Ed for the lesson in lapping a worm. It does sound like a lot of trouble and work.


#28 Charlie B

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Posted 21 December 2012 - 01:35 PM

I got within +-5 arcseconds with the OPB and high precision worm, which was ordered with the G11. I have no experience with the G11 without the OPB and HP worm.

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#29 pfile



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Posted 21 December 2012 - 04:27 PM

What kind of PE should be expected from a brand new G11 with Gemini 2 out of the box. From what I have read in several places about 5 arcseconds peak to peak. Can anyone verify this.
I know how to lap valves on a car when doing a valve job, but how do you lap a worm.


i was a little disappointed by mine... about +/- 16 arcseconds. the absolute value is not as important as the steepest rate of change in arcseconds/second though. that's what tests your guiding setup. unfortunately i've got 2 or 3 places on the worm where the rate of change is pretty high. even with an OAG i'm probably throwing away 35% of my subs due to oval stars.

#30 Geo.



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Posted 22 December 2012 - 11:14 AM

All kind'a reminds me of Colin Chapman's (Lotus cars) early "manufacture" of a custom ratio differential for a racer. He took a stock crown from one diierental and a pinion from another, assembled them, filled the diff with metal polish and ran it until the noise stopped. Then drained, flushed, filled it with oil and went racing!

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#31 pfile



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Posted 22 December 2012 - 12:59 PM

"i've got a chevy with a mopar cam"

#32 JoseBorrero



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Posted 23 December 2012 - 05:49 PM

Well, I installed my OPW-G11 with same worm, but also installed a 50mm mini guidescope with SSAG with an AT6RC f/9, getting flawless 10mins shots. I got the lowest RMS on PHD,same as using a tandem setup; ED80 and a ST80 + SSAG.

Now, I can't tell if the OPW-G11 really improve RMS on PHD as the 50mm mini guidescope was intruduced at same time. Ill have to go back using my OAG TS-9 and check.

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