Hi Ryan,? Did you get this resolved?? I'm seeing the same behavior - though not quite so bad.? I sent my mount back to Scott due to RA oscillations.? He was able to resolve this, and the mount tracks well now, but my dec backlash is over 4000mS while it was typically under 750mS before sending.? I've historically adjusted the DEC SLW per Scotts video with good success but not having any luck now.? I suspect the screws holding the blocks to the plate might need adjustment (which Scott doesn't touch in his video).? I will look at these next.? I would love to hear what you did to resolve your issue.? ? Best, Jim?
|
On Thu, Jan 16, 2025 at 12:53 PM, crocco1250 wrote:
Hi Ryan,? Did you get this resolved?? I'm seeing the same behavior - though not quite so bad.? I sent my mount back to Scott due to RA oscillations.? He was able to resolve this, and the mount tracks well now, but my dec backlash is over 4000mS while it was typically under 750mS before sending.? I've historically adjusted the DEC SLW per Scotts video with good success but not having any luck now.? I suspect the screws holding the blocks to the plate might need adjustment (which Scott doesn't touch in his video).? I will look at these next.? I would love to hear what you did to resolve your issue.? ? Best, Jim?
|
Dale,
?
This seems bizarre behavior. Dec (which should be in red) typically will drift in one direction if PA is off. If seeing is bad it should vary randomly. Having a repeating pattern I think is something software other than hardware as the Dec motor should only be rotating back and forth as corrections are needed.
?
Some random ideas:
-Are RA and Dec cables reversed (probably not)?
-Are you dithering after every frame and is the dither large?
-Have you checked TVC in the hand controller, perhaps too large a value?
-Dec MinMo seems large - I'm seeing changing values from 0.2 to 0.35
-57# on an GM811 seems, like a lot. If a G11 has 60# payload, the 811 is less, I think. Are your counterweights all at the bottom of the CW shaft? Perhaps too much moment-arm the mount can't handle.
?
All I could think of for now.
?
Good luck.
?
John
--
_____________________________________________________________________________________________________________________________________________________________________________
Losmandy G11G2 on pier; refurbed Losmandy G11 with OnStep controller; SkyShed design roll-off observatory; ZWO ASI2600MM-P; ZWO ASI071MC; Sky-Watcher Esprit 100 ED with field flattener; Celestron C925 Edge HD with 0.7XFR, William Optics Zenithstar 61 APO; PHD2, NINA, Sequence Generator Pro and PixInsight user
|
On Sun, Mar 2, 2025 at 12:02 PM, DaleN wrote:
<<SNIPPED>>?
?
OTA is an SVX140T about 28 lbs with 29 lbs counterweight. Am using an OAG at the scope's FL of about 938mm.
?
Is 57 lbs past the limit of the G8 DEC perhaps?
?
Any thoughts on what to try or adjust??
?
Dale
?
Definitely not under mounted.? The generally used rules for determining imaging payload for commodity mounts do not apply to better mounts like Losmandy.? The GM811G has a stated saddle payload for imaging of up to 50 pounds.? This does not include any counterweight.?
?
I had no issues using my vintage GM8s on a Berlbach Planet tripod with a TEC140, M10" f/6.3 LX200 and NS11 SCTs.? The GM811G has almost twice the payload capability of the old GM8s,.you should be GTG
??
--
Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
?
?
?
|
?
Some questions for you.? First, what did the PE look like before it started to misbehave?? Generally when a system is guiding well it generally will continue to guide well until you change something.?
?
So what did you change?? Different scope?? Different auto guiding system? Different guide camera? Did you change your autoguiding software?? Any software updates?? Update ASCOM?
?
What firmware is your Gemini 2 on??
?
Do you have tucked servos and spring loaded worms???
?
--
Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
?
?
?
|
Hope I'm missing something obvious here, but my GM811 guiding has recently seemed impossible to get sorted. I have occasionally been able to achieve 0.5" guiding, but more typically 0.7"-1.2" with current configuration. After breakdown of RA and Dec, replacement clutch pads (Hermann), relube of all bearings, adjustment of worm meshes, gearbox, PEMPro RA 2x worm PEC, etc, I still can't seem to dial this in.
A sample screenshot shows a regular whiplash of DEC, with repeating spikes, which to me indicates some regular periodic roughness of worm gear on the DEC axis? DEC is swinging back and forth here. Could DEC also be affecting the RA numbers?
?
DEC seems to have slight visible play by hand; clutches are tightened about ? turn past touching. Nothing too different than ever.
?
OTA is an SVX140T about 28 lbs with 29 lbs counterweight. Am using an OAG at the scope's FL of about 938mm.
?
Is 57 lbs past the limit of the G8 DEC perhaps?
?
Any thoughts on what to try or adjust??
?
Dale
|
So.... Pier side - What is it? Pier-side, at least its ASCOM definition, is based solely on the mechanical position of the Declination axis. When the scope passes through the celestial pole, the mount's pier-side changes. See here: -Ray
|
On 3/2/2025 11:09 AM, John Kmetz via groups.io wrote: Niel,
Failure to flip usually results from your mount limits not being set right:
please see the following Losmandy video:
<>
John Since a flip is simply a new GOTO after the target passes the meridian, if NINA and the mount do not agree that the target has indeed crossed the meridian the flip will fail. In my case my failed flips were because the mount and NINA did not agree precisely on location and time.? Once that was solved, my flips have been 100% for years. Paul -- Paul Goelz Rochester Hills, MI USA pgoelz@... www.pgoelz.com
|
?
"Another way to think of the "side" of the pier that your scope is on -- it's the side with the center of the saddle. That seems obvious, but if your scope is long and you are near the vertical with the counterweight shaft, the aperture or opposite end of the scope may be across the meridian (or the object you're pointing at is across the meridian.) The saddle is always clearly in one side or the other. This way, it doesn't matter what you are pointing at in the sky, you're always setting a limit or a model for the side that the center of the saddle is on, not what you're looking at."
|
Niel,
?
Failure to flip usually results from your mount limits not being set right:
?
please see the following Losmandy video:
?
?
John
--
_____________________________________________________________________________________________________________________________________________________________________________
Losmandy G11G2 on pier; refurbed Losmandy G11 with OnStep controller; SkyShed design roll-off observatory; ZWO ASI2600MM-P; ZWO ASI071MC; Sky-Watcher Esprit 100 ED with field flattener; Celestron C925 Edge HD with 0.7XFR, William Optics Zenithstar 61 APO; PHD2, NINA, Sequence Generator Pro and PixInsight user
|
Pier side refers to where the telescope is located referenced to the mount itself, regardless of where it’s pointing. For instance, you can have the scope on the west side of the mount pointing east and, later in the session, if your limits allow it, it will go past the meridian and be looking west. All throughout this example, the scope is pier side west.
at least I think this is the right way but, I’ve been proven wrong before so who knows? :)
|
Thanks for the reply, Ed
I'm in the southern hemisphere and using Gemeni 1 - not that either of those factors make an iota of difference to what pier side means..
I think of it as where the telescope is pointing. So in the northern hemisphere, standing behind the mount, west is pointing left and east is pointing right.
?
No expert here, but I believe that is the gist of it.
?
So far as getting meridian flips working, for me it was all about the settings here:
?
?
I would tell you the settings on mine, but it isn't set up right now. If I do soon, I will post again.
?
|
I think of it as where the telescope is pointing. So in the northern hemisphere, standing behind the mount, west is pointing left and east is pointing right.
?
No expert here, but I believe that is the gist of it.
?
So far as getting meridian flips working, for me it was all about the settings here:
?
?
I would tell you the settings on mine, but it isn't set up right now. If I do soon, I will post again.
?
|
Hi All
I know this is not a Losmandy specific question but since I'm STILL struggling with getting automated pier flips to work?with my Losmandy?G11 and N.I.N.A, I figured this would be a good place to start....
I've decided to go?right back to basics and ask some questions that may be construed as "silly", so bear with me.
So.... Pier side - What is it? I know what I THINK it is, but I just want clarification so I can tick that one off my list. Let's say that the Gemini software is saying the scope is pier side West. Is the scope on the west side of the pier? Is the scope on the east side of the pier but pointing west of the meridian
My belief is that in this instance, the scope would be on the west side of the pier (regardless of whether it is pointing to the east or west of the meridian). But what do I know???
-- Thanks and Best Regards Neil
|
Re: RA guiding awful after upgrade
Well, I've had it.? I'm just going to send the whole thing to Losmandy and see if they can figure it out.? My eq6-r is currently guiding at 0.19" and the g11 is doing this.??
|
Re: RA guiding awful after upgrade
On Wed, Feb 26, 2025 at 04:12 PM, Thomas Kallenbach wrote:
I can remove the new RA extension
The 12" extension is much more responsible if the issue comes for these add-ons.? Because the 12 inches of extension increases the inertia the pier must dampen much more that the slight increase from the RA extension.
?
Doug
|
Re: RA guiding awful after upgrade
Hey Thomas,
I've just been following the thread silently as I'm at just as much of a loss as anyone else regarding a definitive source, but I did have a thought:
Your very tight clutch technique may have worked under the pre-RA-extension configuration, but then the RA extension would have extended the moment arm on your RA axis by a few inches. This small difference in moment arm could be just enough to induce a very slight deformation in the RA axis when the clutches are loaded so heavily. I hypothesize that a reduction in that stress will smooth out your guiding, and that stress reduction could come from lowering your clutch pressure or removing your RA-extension, which it sounds like you already have.
I have had my mount for a couple of years now. I also have the RA extension and I was also noticing that my guiding was getting worse. I tried to tighten down my clutches but just couldn't improve it. I had it down to .25-.45 arcsec about a year ago and it just started creeping up to over 1 arcsec even when the seeing wasn't that bad. I tried worm adjustments, clean and relube, clutch pad replacement with Michael Herman's pads; just about everything.
Ultimately, on this forum I came across the advice to have the clutches barely tightened so the mount could easily be pushed if needed. I carefully rebalanced (rolling DEC to 0 degrees) and marked my mounting plate with my saddle so I could easily repeat the position. I tried barely tightening to contact, polar aligned and, hit "Play" in the NINA Advanced Sequencer.
Currently watching the mount settle at .3-.7 arcsec again with none of those severe sawtooth RA excursions like I saw before.
I'm sold on Chip's "barely make contact" with clutch technique.
Also, when I took my axes apart to clean and relube I noticed some wear on the shaft where it touches the needle bearings. I am pretty sure I induced this by over tightening my clutch over time.
?
I can imagine your frustration right now; I bet we have all been there at some time in this hobby, and I hope the RA extension removal gives you some instant satisfaction so you can get some imaging in. But I would encourage you to not give up on the RA extension and give it another shot once you feel like you aren't chasing ghosts in the mount.
Wishing you clear skies and a rewarding imaging session,
Ryan
|
Re: RA guiding awful after upgrade
Thanks Paul.
I decided to remove the RA extension.?
We'll see what happens.
Tom
|
Re: RA guiding awful after upgrade
On Wed, Feb 26, 2025 at 04:12 PM, Thomas Kallenbach wrote:
Hello Everyone,
Tonight might be a clear night so I thought I would set up the scope.? I read in another thread that tightening the clutches excessively could cause jerky movements.? I may have tightened the clutches beyond what was necessary to hold the scope.? I can try it tonight with the clutches only as tight as necessary or, I can remove the new RA extension and see if that makes a difference.? Remember, this problem showed up right after the RA extension and 12" pier extension addition.??
I sure appreciate any advice.? But if I am going to take the RA extension off, I need to get started.
Thank you all,
Tom
Can't give you a definitive advice, Tom, since none of us know for sure what's going on. If you can test with an non-over tightened clutch, first, and then, if that doesn't help, try removing the RA extension. Either one of these seems to be a low-probability solution to me, so do what you think is more likely to give you the answer.
?
Regards,
?
? -Paul
|
Re: RA guiding awful after upgrade
Hello Everyone,
Tonight might be a clear night so I thought I would set up the scope.? I read in another thread that tightening the clutches excessively could cause jerky movements.? I may have tightened the clutches beyond what was necessary to hold the scope.? I can try it tonight with the clutches only as tight as necessary or, I can remove the new RA extension and see if that makes a difference.? Remember, this problem showed up right after the RA extension and 12" pier extension addition.??
I sure appreciate any advice.? But if I am going to take the RA extension off, I need to get started.
Thank you all,
Tom
|
Chip Louie
Ryan Noonan
Ed Harp
Paul Kanevsky