I'm in the process of cleaning/regreasing again, and this time noticed when reassembling that there is a definite stiff section when rotating the RA main spur gear by hand with the clutch moderately tightened (the worm is NOT installed).? I believe that the RA bar is not quite square to its upper plate, resulting in the two surfaces that are compressed together? not coming together uniformly.? This is a terrible explanation, so please see the picture in the link, where I have removed the clutch pad to visualize the gap (on the left, which is then on the right when rotating the RA axis by 180).
Now I'm sure this has always been this way and I've just never noticed, so just wondering if there's anything not extremely invasive I can do about, or whether I should just move on and ignore?
Thanks,
Keith
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Re: Losmandy GM8 periodic error
Hi, ? Yes, I know the paper Michael made and that was the main reason I started modifying the mount. And I have to admit I love this part J Also because I have I friend with the same mount and we are a team on this journey J ? The hard part now is waiting for parts. ? Catalin ? __ Catalin Paduraru Tel: (004) 0722.22.75.94 ?
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From: Losmandy_users@... [mailto:Losmandy_users@...]
Sent: Sunday, January 21, 2018 10:47 PM
To: Losmandy_users@...
Subject: [Losmandy_users] Re: Losmandy GM8 periodic error? ? Hi Catalin, Have you read Michael Herman's document in the files about how to optimize your G11 mount? It is the definitive piece for the G11 and GM8 mounts! Shoot me you mailing address and I'll send you the correct Bellevue spring washers. Wave washers are not going to work.
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Re: Losmandy GM8 periodic error
Hi Catalin,
Have you read Michael Herman's document in the files about how to optimize your G11 mount? It is the definitive piece for the G11 and GM8 mounts! Shoot me you mailing address and I'll send you the correct Bellevue spring washers. Wave washers are not going to work.
Chip ??
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Yes it can. I run my entire system remotely from my house. I use the G11 Ethernet port with a local router. My cameras are ethernet enabled as well as my focuser.
Works great. I can make all night runs unattended.
Doug Bock
From: Losmandy_users@... [mailto:Losmandy_users@...]
Sent: Saturday, January 20, 2018 3:45 PM
To: Losmandy_users@...
Subject: [Losmandy_users] remote operation
I've got a G11 with NGC Max digital setting circles. I'm considering the Gemini system. I see GPS is available. Can it be run remotely? When it's cold I'd like to be able to keep warm and operate it from my house.
[Non-text portions of this message have been removed]
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Anon,
Yes, it can be run remotely, however, this is a lot more challenging.
I have a Raspberry Pi 3 running INDI which controls my mount, imaging and guide cameras and focuser which I remotely access from my Mac.
There are a number of ways this can be achieved but I do it with VNC.
Regards
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I've got a G11 with NGC Max digital setting circles. ?I'm considering the Gemini system. ?I see GPS is available. ?Can it be run remotely? ?When it's cold I'd like to be able to keep warm and operate it from my house.
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I've got a G11 with NGC Max digital setting circles. ?I'm considering the Gemini system. ?I see GPS is available. ?Can it be run remotely? ?When it's cold I'd like to be able to keep warm and operate it from my house.
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Re: Losmandy GM8 periodic error
Hi guys,?
Thank you for your feedback.?
Chip
I think I can do all this improvements without damaging the mount. At least part of the hobby is improving my gear and I have experience over the years :)? I believe?the mount has it's stock specs now. All I want to do is to improve a bit the periodic error. If I'm not happy with the results I will buy the HP worm. At least this is the plan. I don't think I need the OPWB for what I do but will see. For polar align I'm using the Losmandy polar finder. Is good enough for now. I will try SharpCap also. I couldn't find belleville washer in my country or ebay so I ordered wave washer. I hope they will do the same job.
Mark
I have the stock mount with?492 digital drive. And using the mount to do astrophotography using 600mm focal length and DSLR camera.? You have good improvements with your mount.?
For the next clear night I want to try and get the best mesh setup for this worm. And after this I will do the same with the DEC worm. And I have another worm from a friend and try his worm to. And see which worm performs better.?
And I will return with the error to see how good it can be with steel worm, ABEC 5 bearings, wave washer and my version of OPWB.?
Catalin
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Re: Losmandy GM8 periodic error
Catalin, ? My experience was with a used (made around 2006 I recall ¨C it has the 25 year sticker on it) G-11. I was the second or third owner. I think the first owners bought it and did not know how to adjust it properly. ? I started out in the same place with about 40 arcseconds of swing in the pattern and it included the dreaded 76 second ?(of time) spike in the pattern, which PEC can not take out. That is usually a result of miss-alignment of the bearing blocks on the worm. ? I did the following: ? Replaced the steel worm gears (I did both) with the brass high precision worms. So of course this meant I cleaned and re-greased the worm wheels as well. ? Replaced ?the worm shaft bearings with upgraded ones like you are talking about. ?I also replaced the bearing blocks (two per worm) because the prior owner had seriously over torqued the bearing blocks. Since the metal is thin and the bearing blocks were cheap I replaced them. Perhaps not necessary. ? Carefully aligned the bearing blocks by installing them with the mounting bolts finger tight. Then I clamped a metal angle bracket to them (with small soft-jaw clamps) to keep them parallel. Then I adjusted the worm to worm wheel spacing (often referred to as the ¡®lash¡¯) to find the high spot on the worm and carefully tightened the worm blocks in place. This took a bit of practice but I was able to completely eliminate the 76 second problem . This was before the one-piece worm blocks were available. But I haven¡¯t had to change it since 2007. ? Carefully mounted the motors so the Oldham couplers were square and parallel. ? By doing the above I got the PE down to about +-4 arc seconds, which put it well within range of an autoguider since the slope would be about 4arc sec/60 seconds. So during a three second guider exposure the accumulated error would be 12/60th = 0.2 arc seconds, which you¡¯ll never see given the atmosphere. ? I hope you are not trying to image moderate to long focal lengths without guiding. ? I assume you have a non-Gemini mount. You didn¡¯t say if it was the 492 or the Gemini drives. Some of the other responses, I think, assumed you had the Gemini since they talked about gearboxes. If you have the Gemini, of course, that is something else to worry about. ? Hope this helps you. ? Choi, ? Mark Christensen ?
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Re: Losmandy GM8 periodic error
Hi Catalin,
If you are capable of doing the mechanical work without damaging the mount and the mount ihows no obvious damage your GM8 should be capable of pretty good tracking. With any project like this you have to be honest with yourself in recognizing your abilities and your limitations to avoid causing more harm than good. That said the basics are the most important considerations. This is what I always do with any equipment I buy new or used. Assess the baseline performance of the system in front of me to see if it meets the needs of the project or use. If the answer is yes use it as is.?
If the answer is no, document performance problems then determine what can be done to bring the system into operational condition. For a high quality mount like the GM8 this should be simple as long as there is no obvious damage, just bring the mount back to manufacturer's stock condition before chasing improved performance. To do this you need to disassemble, remove old lube fully using solvent and blow bearings and all surfaces clean and dry, inspect and assess condition of component parts, replace or repair any components that are not in top mechanical condition. Correctly lubricate (minimal fresh lube) using correct lube for expected environmental conditions and reassemble and verify correct assembly, do not rely on as received assembly order, if in doubt ask here or refer to assembly photos. Adjust worm mesh and reassess performance using the same system used for baseline data. Be sure that your measurement system is valid, if in doubt ask here or on sites that support your autoguider software and hardware.?
Once you have a good working mount and you know the mount is working correctly and is as well adjusted as possible in my experience the single largest improvement to tracking error is changing from the old silver steel colored worms to the brass colored high precision worm on the RA axis. The second option with the most impact on tracking or PE is to put that HP-worm in a one-piece worm block. Other than these two updates careful assembly and adjustment like adding Bellevue spring washers and using good clean bearings on the worms make all the difference. The most obvious issue that adversely affects every EQ mount's tracking error is polar alignment. What to you use to do your polar alignment? The best method I have seen and used is the PoleMaster camera but if you have an autoguider you can also use SharpCap 3.x which can also give you an excellent polar alignment, these two are the best of what I have used.? ? Chip Louie ?
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Hi Magnus,
What I am suggesting you might try is to loosen the two fasteners that attach the servomotor to the gearbox. Then slightly moving the servomotor around during a long slew and find the spot that the gear and servo noise is minimized. At that point gently snug down the fasteners and retest.??
If the gearboxes have places in their rotation that have higher resistance this may be a small part of the problem but this may not have a large influence in the tracking error. Here is what I have seen when I got two brand new gearboxes from Losmandy when I bought a full Gemini 2 kit. These new gearboxes had places that had spots that were harder to turn the gearbox shaft. But you have to realize that you are turning the gearbox on the OUTPUT side of the gearbox. Here you are feeling an increase in resistance that is amplified by the 25:1 gearbox ratio. The servomotor sees a much smaller resistance, how much is dependant on the particular pair of gears that have the tight backlash, additionally the motion on the servomotor side of the gearbox is much smaller. What I am saying is that I am not certain this small additional resistance can make much of a difference once the motion is reduced even more by the worm gear ratio.?
The flipside is a gearbox with excessive backlash. IMO this would be worse than a gearbox with slightly tighter clearance and minimal backlash because the servomotor which when controlled by an autoguider would speed up and slow down loading and unloading the gearbox which would make the autoguiders job harder to do as it would always be chasing the unpredictable backlash of the gearbox.?
I have not tested this notion with my very old gearboxes which are very free turning. Given the time required to setup and test the tracking error of my G11G as is, then change out the RA gearbox and retest with the old loose gearbox seems like a summer time warm weather project. Maybe if I find some spare time I can test this out but at the moment it's January and even here in SoCal it's cold.?
Chip ? ?
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Re: Losmandy GM8 periodic error
Your first big win will be very likely from the worm gear mesh adjustment, that's definitely worth doing. I got a large improvement on my mount just be doing that.
Clear skies
Dave Partridge
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-----Original Message-----
From: Losmandy_users@... [mailto:Losmandy_users@...]
Sent: 19 January 2018 08:19
To: Losmandy_users@...
Subject: [Losmandy_users] Losmandy GM8 periodic error
Hi guys,
This is my first post on this group. Sorry for my english, I¡¯m not a native speaker.
I have an old GM8 mount which I want to improve. The actual periodic error is about 54 arc/sec peak to peak. I have the steel worms and two block design. I¡¯ve attached a picture with PECPrep graphs.
My questions are:
1) Can I improve the actual error using the steel worm?
2) If I change to a high precision worm from Losmandy what would be the best PE I can get? How much better than now? To know what to expect.
3) Can I find the mount¡¯s year of production by viewing the serial number? The serial number is HGM299805084.
What I want to do next to gain some improvements:
1) Change the bearings with new ABEC 5 bearings.
2) Spring washer on one bearing to tension the worm between the blocks.
3) Play with the mesh to find the hot spot.
What I did till now:
1) Clean and grease the mount.
2) I found that at transport the blocks that press the needle bearing and hold the RA axis were misaligned. So I pressed them together to a true. I¡¯ve read about this here on the group.
3) Make a version of OPW. You can see it in the attached picture.
I¡¯ve searched a lot on internet about performances of GM8 but very few details I found. So you are my last chance J
Any suggestions are welcome.
Catalin
[Non-text portions of this message have been removed]
------------------------------------
Posted by: "Catalin Paduraru" <catalin.paduraru@...>
------------------------------------
------------------------------------
Yahoo Groups Links
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Hi!
What is the "sever motor pinion"? English is not my first language... and technical terms are a bit tricky at times.
But, OK, I can do that. But still, the "rough" spot on the gear box revolution - that is without the motor attached. Should that be OK or should I do something about it?
Magnus
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Losmandy GM8 periodic error
Hi guys,
This is my first post on this group. Sorry for my english, I¡¯m not a native speaker.
I have an old GM8 mount which I want to improve. The actual periodic error is about 54 arc/sec peak to peak. I have the steel worms and two block design. I¡¯ve attached a picture with PECPrep graphs.
My questions are:
1) Can I improve the actual error using the steel worm?
2) If I change to a high precision worm from Losmandy what would be the best PE I can get? How much better than now? To know what to expect.
3) Can I find the mount¡¯s year of production by viewing the serial number? The serial number is HGM299805084.
What I want to do next to gain some improvements:
1) Change the bearings with new ABEC 5 bearings.
2) Spring washer on one bearing to tension the worm between the blocks.
3) Play with the mesh to find the hot spot.
What I did till now:
1) Clean and grease the mount.
2) I found that at transport the blocks that press the needle bearing and hold the RA axis were misaligned. So I pressed them together to a true. I¡¯ve read about this here on the group.
3) Make a version of OPW. You can see it in the attached picture.
I¡¯ve searched a lot on internet about performances of GM8 but very few details I found. So you are my last chance J
Any suggestions are welcome.
Catalin
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Hi All,
I think the 32 second period is how long it takes for the standard Losmandy gearbox intermediate gear to make one revolution. You could try adjusting the servo motor pinion by loosening the fasteners on the servo motor and moving the motor around and listen for the quietest position. sounds crazy but this made my Gemini 2 mini better when I first installed it.
Chip??
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Actually, I found that it may be possible to open the gearbox. I replaced one recently, and the new one shows that there are 3 small hex screws, two about across from the shaft, and one at the bottom end. On my original gearbox, they are covered with something like black paint that might be able to be removed. If the screws aren't covered, they are very easy to remove and disassemble the gearbox. It's not hard to reassemble. In fact, I tried swapping out parts from my old and new gearboxes to see which combination worked best, but I settled for just using the new one.
-Joe
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Windows Update KB4056892 causes disconnect errors for Astronomy Programs
Windows 10 update KB4056892 (and we now know that KB4056898 for Windows
8.1) causes DCOM errors.? This can keep Astronomical programs and
drivers that depend on
DCOM from connecting to the Gemini.net driver.
Mr. Bob Denny discovered the cause of this error, and also a work-around
to fix it.
Please see for links to both
his tests and work around.
Best
Tom Hilton
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Re: Perplexing RA Behavior
Hi David,
I think the groups.io group server is an excellent system. Modern and up to date with several popular sites to be added using their integration feature. I set up a private group for my astronomy club to try out and it works well and is easy to configure and maintain. The top tier paid service is much more flexible of course than the free version I set up for demo but you can get the idea from the free version. I like it.
Chip
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Hi all!
Latest update on this:
Today I switched gearboxes. I installed a brand new gearbox for RA in December. Now I switched back to the original. WHen examining them, I find that the brand new one rotates easier than the original. However, on the new one, there is point in each turn of the worm, where there is more resistance. On the original one, it is smooth and no perceptible differences in smoothenss during the whole turn. However, the original one turns slightly less easy - but smoothly.
So I switched back to the original, to see if that makes a difference.
But should there really be such a point with resistance on a brand new gear box?
On the other hand: this point of resistance is when I turn the knob that turns the worm. So once each revolution would mean a period of 4 mins, right? That does not fit with the 32 secs osciallation. Anyone has any idea of where to more specifically locate the source of that 32 sec oscillation? The gearboxes are closed, so I cannot open and count teeth....
Best,
Magnus
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Re: Perplexing RA Behavior
Hmmm maybe time to consider moving over to groups.io form the increasingly unreliable Yahoo! L
Dave
From: Losmandy_users@... [mailto:Losmandy_users@...]
Sent: 13 January 2018 19:03
To: Losmandy_users@...
Subject: [Losmandy_users] Re: Perplexing RA Behavior
This is bing posted on behalf of Derek Breit due to a Yahoo Groups issue.
----------------------------------------------------------------------------------------------------------------
Chip-
I seem to not be able to send email to any of my groups, so would you kindly forward this to the Losmandy Group.. please..
Derek
_____
From: Derek C Breit [mailto: <mailto:breit_ideas@...> breit_ideas@ poyntsource.com]
Sent: Wednesday, January 10, 2018 6:53 PM
To: ' <mailto:Losmandy_users@...> Losmandy_users@yahoogroups. com'
Subject: RE: [Losmandy_users] Perplexing RA Behavior
My G11 holding around 27 pounds of 5¡± Triplet and accessories would slip with my original clutches completely tightened with the Captains knobs whenever I would loosen the saddle to slide the scope to and fro / wouldn¡¯t hold the counterweights horizontal with no scope attached.. My Michael Herman Clutch Disks arrived today..
They *appear* to be of an awesome material compared to the original!
Derek
PS.. Thanks Michael!
**UPDATE**
(I cleaned and relubed the bearings and installed clutch plates..)
Michael¡¯s clutch plates are Spectacular.. Night and day from what I had, which were like polished Teflon.. I have projects the next two days, so I may not get to try it all out in action before the next rain, but just setting on the table, the difference is obvious.. It *seems* rather tight, yet I have many turns left on the Knobs.. In actual use previously, my knobs have been completely tightened..
Derek
[Non-text portions of this message have been removed]
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Re: Perplexing RA Behavior
This is bing posted on behalf of Derek Breit due to a Yahoo Groups issue. ----------------------------------------------------------------------------------------------------------------
Chip- I seem to not be able to send email to any of my groups, so would you kindly forward this to the Losmandy Group.. please.. ? Derek ?
From:?Derek C Breit [mailto:breit_ideas@ poyntsource.com]?
Sent:?Wednesday, January 10, 2018 6:53 PM
To:?'Losmandy_users@yahoogroups. com'
Subject:?RE: [Losmandy_users] Perplexing RA Behavior ? My G11 holding around 27 pounds of 5¡± Triplet and accessories would slip with my original clutches completely tightened with the Captains knobs whenever I would loosen the saddle to slide the scope to and fro / wouldn¡¯t hold the counterweights horizontal with no scope attached.. My?Michael Herman?Clutch Disks arrived today.. ? They *appear* to be of an awesome material compared to the original! ? Derek PS.. Thanks Michael! ? **UPDATE** (I cleaned and relubed the bearings and installed clutch plates..) ? Michael¡¯s clutch plates are Spectacular.. Night and day from what I had, which were like polished Teflon.. I have projects the next two days, so I may not get to try it all out in action before the next rain, but just setting on the table, the difference is obvious.. It *seems* rather tight, yet I have many turns left on the Knobs.. In actual use previously, my knobs have been completely tightened.. ? ? Derek ?
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Doug Bock
David C. Partridge