dickbill
professor emeritus
Reged: 09/30/08
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Re: CGEM motor cogging
[Re: Patrick]
#5749616 - 03/22/13 12:47 PM
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well, we are being finicky here. These issues are probably of no consequences at focal lenght under 1500 mm. It's only when you go over that that you need to consider all the smallest issues.
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orlyandico
Carpal Tunnel
Reged: 08/10/09
Loc: Singapore
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Re: CGEM motor cogging
[Re: dickbill]
#5749961 - 03/22/13 03:27 PM
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not really.. the 8/3 on mine is so huge that even 500mm unguided is problematic..
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Mike X.
professor emeritus
Reged: 06/28/10
Loc: Greece-Athens and Rome-Italy
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Re: CGEM motor cogging
[Re: orlyandico]
#5750026 - 03/22/13 03:58 PM
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I'm getting more and more convinced towards an atlas or the new azeq6pro...I would love to have a Cgem but...not the 8/3 error...
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rmollise
Postmaster
Reged: 07/06/07
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Re: CGEM motor cogging
[Re: Mike X.]
#5750207 - 03/22/13 05:16 PM
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Don't forget the original Atlas. Cheap. Robust. Known quantity...hard to go wrong with it.
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Geo.
Carpal Tunnel
Reged: 10/01/08
Loc: Upstate NY
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Re: CGEM motor cogging
[Re: Mike X.]
#5750246 - 03/22/13 05:31 PM
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Quote:
I'm getting more and more convinced towards an atlas or the new azeq6pro...I would love to have a Cgem but...not the 8/3 error...
Of course these use stepper motors, which can have their own issues, but advanced drivers can keep a stepper energized to hold it between steps. This sounds like what Celestron is trying to get to, I guess.
The Nexstar SE6/8 mounts use an Indian made motor. The 5/8 and 5/8i mounts used Pittman Lo-Cog drives. I think were found in the CGE and the Meade LX200GPS 16" mounts. Too bad these aren't a swap out, I have a box of them. The Lo-Cogs have "twisted" amature cores so no one spot is attracted to one field magnet.
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Mike X.
professor emeritus
Reged: 06/28/10
Loc: Greece-Athens and Rome-Italy
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Re: CGEM motor cogging
[Re: Geo.]
#5750334 - 03/22/13 06:17 PM
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Very true Rod 
Geo..true..steppers have their cons too but so far the SW seems to have a better record.
I am a celestron fan personally... But if the steppers provide me the same tracking resolution with they servo counterparts that's what made me think I favor of them,
Edited by Mike X. (03/22/13 06:29 PM)
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tboconnor
member
Reged: 01/14/10
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Re: CGEM motor cogging
[Re: Mike X.]
#5751122 - 03/23/13 02:11 AM
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I just checked mine - when I set the rate to 2, and look at the RA and DEC numbers, I dont see any pauses or movement back when moving the mount.
Does this mean I dont have a cogging issue?
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Raginar
Carpal Tunnel
Reged: 10/19/10
Loc: Rapid CIty, SD
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Re: CGEM motor cogging
[Re: tboconnor]
#5751436 - 03/23/13 09:46 AM
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tboconnor,
You won't see it until you're guiding. Your PHD graph will have a 'sawtooth' pattern in declination.
Very frustrating, and the reason most of us get rid of our CGEMs. Mine was 'fixed' via hypertuning (thanks Ed!) but only at lower weights than I wanted (<20# was the sweet spot for my particular mount).
I was up front when I sold it.
Chris
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svtdoug
sage
Reged: 02/07/11
Loc: Gig Harbor, WA, USA
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Re: CGEM motor cogging
[Re: tboconnor]
#5753006 - 03/23/13 11:37 PM
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Quote:
I just checked mine - when I set the rate to 2, and look at the RA and DEC numbers, I dont see any pauses or movement back when moving the mount.
Does this mean I dont have a cogging issue?
With the mount balanced in Dec, if you are pressing short (about half a second) blips with the hand control in dec, and the dec numbers continue to go up or down, without any hangups, or rollback, then you likely do not have the issue. Do check both directions though. Check going one way for a minute of short bursts, then reverse and check the other direction for a minute or so. But as Chris suggested, check your PHD guiding graph for any sawtooth pattern in dec to make sure. If you want more information on this check - I posted a video further up this thread.
Cheers,
Doug
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svtdoug
sage
Reged: 02/07/11
Loc: Gig Harbor, WA, USA
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Re: CGEM motor cogging
[Re: svtdoug]
#5787300 - 04/09/13 02:44 AM
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Just a quick update on the cogging issue. We received a new beta motor control firmware version from Celestron about a week ago for testing. The early test result are encouraging. The dec cogging seems to be cured, no sign of it from any testers. There are several intermittent issues that we and Celestron are dealing with, but those might be due to other things than the firmware, a sick RA motor in my case. I have done a lot of testing, but all indoors, as we have had non-stop cloud cover since the beta release. Other tester have been able to guide and the results are good, so far.
The bottom line is that Celestron heard from the user community and put the resources where they need to be to get this problem solved. Hopefully there will be a stable version soon for public release.
Thanks for all who commented about this issue.
Doug
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jonbosley
professor emeritus
Reged: 10/19/05
Loc: Texas
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Re: CGEM motor cogging
[Re: svtdoug]
#5787849 - 04/09/13 11:21 AM
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That is very good news Doug I am glad Celestron are finally addressing the issue, it has most likely hit sales as they have know about this issue for a long time.
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Raginar
Carpal Tunnel
Reged: 10/19/10
Loc: Rapid CIty, SD
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Re: CGEM motor cogging
[Re: jonbosley]
#5788079 - 04/09/13 01:13 PM
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That was always the problem in the past. They had some software ideas to get rid of the cogging, but it always hard broke some other routines.
Hopefully they can figure it out. I really liked my CGEM.
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Mike X.
professor emeritus
Reged: 06/28/10
Loc: Greece-Athens and Rome-Italy
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Re: CGEM motor cogging
[Re: Raginar]
#5788227 - 04/09/13 02:07 PM
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I'm really glad they come out with a fix!!! Thats great news!! (even if i just bought an azeq6gt 2 weeks ago...Couldn't wait anymore )
Edited by Mike X. (04/09/13 02:10 PM)
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dickbill
professor emeritus
Reged: 09/30/08
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Re: CGEM motor cogging
[Re: Mike X.]
#5788574 - 04/09/13 04:01 PM
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That's great news. Assuming that happens and we can download the upgrade from C, does it require a special cable ? i never did that.
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Raginar
Carpal Tunnel
Reged: 10/19/10
Loc: Rapid CIty, SD
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Re: CGEM motor cogging
[Re: dickbill]
#5788598 - 04/09/13 04:15 PM
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Dickbill, you'll need a cable like you use to do computer control.
Also, they thought they had this fixed last year too. Don't hold your breath. The guy who does it ends up getting pulled to work other projects; they already have your money 
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svtdoug
sage
Reged: 02/07/11
Loc: Gig Harbor, WA, USA
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Re: CGEM motor cogging
[Re: Raginar]
#5813822 - 04/21/13 06:48 PM
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I'm pleased to report that beta testing is going well for the CGEM motor control firmware update that addresses the Dec cogging issue. We are testing the second version this month and results are very good - no dec cogging, and dec RMS values of 0.25 pixels during guiding has been achieved.
But, we need more testers. If you have a CGEM, and are somewhat familiar with updating the firmware via MCUpdate, and can do somewhat controlled tests and write concise reports of the results, and would like to participate - here is how:
1. Go to Teamcelestron.com and register as a member.
2. If you don't already have MCUpdate and HCUpdate installed on your computer, go to the Celestron website, download and installed these two programs. These are the required programs to update your mount's firmware.
3. Go back to the TeamCelestron website, click on the Firmware link, then the Motor Controller section, then the Version 31.07 section. Read through this section to get an idea of what is going on. It also would not hurt to read through the previous version 30.91 thread to see what issues have come up and have been resolved.
4. Download the 31.07.cel file. Its in the first post by Derik in the 31.07 section and install it in your Motorcontroller folder (which will be created on your computer when you install MCUpdate.exe).
5. Run MCUpdate.exe. The beta version 31.07 will now be in the list of available firmware updates. Select it and load it into your mount for both axis - Azmith and Alt.
6. Read all the disclaimers about testing beta firmware, understand the risk, and please test every function that you have ever used with your mount. All the utilities and Setup functions. You can do a lot of testing indoors if you have cloudy conditions. Of course, setup, aligning, ASPA, and guiding under the stars is the best test.
The more testing we can accomplish, the quicker this version will be released to the public.
If you have any questions, please ask!
Thanks!
Doug
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gmartin02
sage
Reged: 04/11/05
Loc: Santa Clarita, CA
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Re: CGEM motor cogging
[Re: Raginar]
#5813959 - 04/21/13 08:18 PM
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That was always the problem in the past. They had some software ideas to get rid of the cogging, but it always hard broke some other routines.
Hopefully they can figure it out. I really liked my CGEM.
This is incorrect. The other big introduced problem (that was so hard to track down) in the firmware that addressed the Dec cogging issue was unrelated to the Dec cogging fix. It's a long story, but available by reading the TeamCelestron motor control forum posts.
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amdizack
member
Reged: 08/23/12
Loc: Goodyear, AZ
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Re: CGEM motor cogging
[Re: gmartin02]
#5814006 - 04/21/13 08:41 PM
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I have had my CGEM for 6 months, and just noticed this issue last night. I ONLY had the issue when I was imaging East of the Meridian. Anything I started tracking in the West came out just fine.
Does this fit into the category of this CGEM issue? Or would I see it East AND West of the meridian?
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gmartin02
sage
Reged: 04/11/05
Loc: Santa Clarita, CA
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Re: CGEM motor cogging
[Re: Raginar]
#5814008 - 04/21/13 08:41 PM
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Dickbill, you'll need a cable like you use to do computer control.
Also, they thought they had this fixed last year too. Don't hold your breath. The guy who does it ends up getting pulled to work other projects; they already have your money
If you were holding your breath, it might be almost time to exhale.
As Doug said above, we have gotten 2 new beta versions in the last 3 weeks, and the latest version is guiding really well in Dec (for me now better than guiding in RA). We could use some more beta testers.
Note: The new motor control firmware is based on "beta" code (not just a tweak to the existing release code, but a re-write from scratch), and has not been thoroughly "fine tuned" yet for public release. That being said, I am now able to use the current beta MC release for multi hour unattended guided imaging without issues.
"The guy who does it..." actually has a name, which is Derik.
Derik, you rock!
Greg
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gmartin02
sage
Reged: 04/11/05
Loc: Santa Clarita, CA
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Re: CGEM motor cogging
[Re: amdizack]
#5814208 - 04/21/13 09:56 PM
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I have had my CGEM for 6 months, and just noticed this issue last night. I ONLY had the issue when I was imaging East of the Meridian. Anything I started tracking in the West came out just fine.
Does this fit into the category of this CGEM issue? Or would I see it East AND West of the meridian?
My CGEM initially had more problems Dec guiding close to the pole. With more use, as the mount continued to break in, the Dec cogging issue appeared to become worse across all latitudes, regardless of which side of the meridian I was guiding on. I wonder if the object(s) you were guiding on East of the meridian was higher in celestial latitude than the object(s) West of the meridian?
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