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Re: G11G RA Clutch
I dunno Chip, maybe it's just my mount. ?But it is horrible cranked tight. ?So horrible that imaging isn't possible. ?It basically turns that beautiful mount into a visual only mount. ?
At this point I'm not too concerned because it's just plain working now so I'm happy. ? BTW, your arc-sec rms is super good. ?I hope to get mine there in time. ?Still getting used to using it. -Rich- |
Re: File - Guidance on Posting Documents and Pictures.doc
You have to do it yourself. Here's the link.
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losmandy_users-unsubscribe@... Don ----- Original Message -----
From: "'George Seitz' gwsarch@... [Losmandy_users]" <Losmandy_users@...> To: <Losmandy_users@...> Sent: Wednesday, November 01, 2017 4:04 PM Subject: RE: [Losmandy_users] File - Guidance on Posting Documents and Pictures.doc Please delete me from your email. |
Re: G11G RA Clutch
The open design of the Losmandy drive system makes working on it rather easy. But it leaves open the potential for airborne dust or grit to get in there and wreck havoc with the operation.?? That is just our nightmares on a clear moonless windless night... ready to image when a drive glitch appears. I hope you sort out the trouble.? So far, I have not got that particular trouble... (did I say... so far?) - Best? Michael? On Wed, Nov 1, 2017 at 1:56 PM, tazercn@... [Losmandy_users] <Losmandy_users@...> wrote:
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Re: G11G RA Clutch
Michael, my issue may be different than Rich's but what I'm experiencing seems like a bearing popping and some slight stiction/backlash afterwards where PHD has trouble getting RA back to the center line. Once it does it stays there nicely until it pops again. Mine's only about 2" (I'm imaging at ~0.5" ppx using an OAG) so it looks like seeing but it only happens in one direction.
Figured the stiction/backlash might be due to the Belleville washer I installed a while back (before I increased the payload) so I removed it and saw the same behavior. Read a bit about removing backlash with the original opwb and I had been doing it by loosening one bearing block only. I figured it might be 'twisting' the bearings causing something like the old 76s error. So I took care to loosen/tighten both blocks together when adjusting backlash. Still I see the same behavior. Next I suspected it could be related to the Oldham, so I carefully aligned the gearbox-oldham-worm axis so that it would all spin freely before installing the servo. Same behavior. I had been thinking it was potentially grit or damage in the gearbox and was planning on replacing it with a brand new spare I have in the closet. I was also considering putting the old bearing back in, I had upgraded to ABEC7's when I put in the Belleville washer, in case one of the new ones were damaged somehow. I'll do the clutch test soon and see if that has any effect. I'll start off with it tight (like normal) and then incrementally back off on it until the scope starts slipping. If that doesn't work I'll do the bearings and gearbox swap at the same time. Mark |
Re: G11G RA Clutch
Rich,
That sounds odd to me. When I got my updated G11 to a G11G and tested it I cranked the clutches down as usual and saw no measured changes in tracking error. I have always cranked the clutches down pretty firmly for Gemini use and imaging with very good results. Maybe I should try retesting with the clutches set looser than normal to see if the PE improves though it seems unlikely as my PE is already low when unguided and guided my G11G is 034-0.41 arcsecond range which seems good enough.?I also have tested the current draw using a precision bench power supply and there is zero difference in current draw duty cycle and lag rates when cranked down super tight and loose enough to use in PUSH-TO mode. This is on a Losmandy G11 Scott had retrofitted as fully optioned G11G spec mount with w/Gemini 2-mini and high torque servo motors.? Chip |
Re: File - Guidance on Posting Documents and Pictures.doc
George Seitz
¿ªÔÆÌåÓýPlease delete me from your email. ? From: Losmandy_users@... [mailto:Losmandy_users@...]
Sent: Wednesday, November 01, 2017 9:01 AM To: Losmandy_users@... Subject: RE: [Losmandy_users] File - Guidance on Posting Documents and Pictures.doc ? ? Please delete me from your email. ? From: Losmandy_users@... [mailto:Losmandy_users@...] ? ?
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Re: G11G RA Clutch
That's unfortunate and I don't find that clutch effect on worm gear to ring gear spacing on the old CG11 that I have, or the newer GM8.?? I wonder if it has to do with the extra new Belleville spring washer I think they installed in the newer systems.? Nothing should affect the worm as the ring gear only rides on the upper flat needle bearing system.? That is not affected by the clutch...or it should not be if the ring gear surface is flat and perpendicukar tobthe axis and parallel to the upper driven plate (Are they?) Only you can run this experiment: see if that spring washer is in there and remove it.? You shouldn't need it anyway...it was installed to make the axis move more freely for scope balance.? Would your worm gear behavior work better (no effect of clutch knob) if the spring is removed? Anyway, its an unwelcome puzzle to figure out.?? best, Michael? On Nov 1, 2017 12:29 PM, "sornborger@... [Losmandy_users]" <Losmandy_users@...> wrote:
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Re: G11G RA Clutch
Glad you figured it out. I'm actually experiencing something similar where I'm getting 2-3" spikes in RA consistently while my DEC guiding is very solid (1-2" RMS in RA, .3-.4" in DEC). I haven't measured the spike period but 30-40 seconds sounds about right.
My only semi-recent change was putting a larger scope on, so I'm running about 40lbs of gear. Since I use the system visually, I tend to crank down on the clutches to prevent the scope from moving when I change eyepieces (heavy ones anyway). I bet I've got the clutches way too tight. I'll chime in with my results as well when I get a chance to setup again. Thanks again for sharing your experiences and solutions. Mark |
Re: File - Guidance on Posting Documents and Pictures.doc
tom
You have to go to Losmandy Yahoo Groups and delete yourself.
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On 11/1/2017 12:01 PM, 'George Seitz' gwsarch@... [Losmandy_users] wrote:
Please delete me from your email. |
Re: File - Guidance on Posting Documents and Pictures.doc
George Seitz
¿ªÔÆÌåÓýPlease delete me from your email. ? From: Losmandy_users@... [mailto:Losmandy_users@...]
Sent: Tuesday, October 31, 2017 8:23 PM To: Losmandy_users@... Subject: [Losmandy_users] File - Guidance on Posting Documents and Pictures.doc ? ?
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Re: G11G RA Clutch
¿ªÔÆÌåÓýThat sounds like good progress ;) ? ? Brian ? ? Brian Valente Brianvalentephotography.com ? From: Losmandy_users@... [mailto:Losmandy_users@...]
Sent: Tuesday, October 31, 2017 7:35 PM To: Losmandy_users@... Subject: [Losmandy_users] Re: G11G RA Clutch ? ? Ok, I've found out that on my mount tightening that clutch screw tight does indeed ruin auto guiding. ?Backed off half a turn has turned my guiding into .5 RA guiding without those huge spikes. ? So the little flat thrust bearing hates to be squeezed too tight. ?It protests. ? -Rich- |
Re: G11G RA Clutch
I feel better now, Brian! 5 arcsec I can believe.?? All the best, Michael? On Oct 31, 2017 1:56 PM, "'Brian Valente' bvalente@... [Losmandy_users]" <Losmandy_users@...> wrote:
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Re: G11G RA Clutch
¿ªÔÆÌåÓýI am ¨C I forgot that! ? But no, I wasn¡¯t there, sorry ? Thanks ? Brian ? ? Brian Valente Brianvalentephotography.com ? From: Losmandy_users@... [mailto:Losmandy_users@...]
Sent: Tuesday, October 31, 2017 4:09 PM To: Losmandy_users@... Subject: [Losmandy_users] Re: G11G RA Clutch ? ? Hi Brian, ? I think you're an LAAS member. Were you at Mt Wilson a few weeks ago?? ? Chip ? |
Re: G11G RA Clutch
At 21:56 31-10-17, 'Brian Valente' bvalente@... [Losmandy_users] wrote:
Rich, Regarding the RA clutch disk, I could have sworn Losmandy switched to a new better clutch system than the plastic ones, or at least they have it as an upgrade, you might call them and ask. Apparently this happened c. 2015. See: David |