Just with in the last 3 weeks, I have issues with the G11 RA and Dec motors (I think).? Even if the hand control is set to slew, both motors move the telescope very slow. The
mount was powered with 110 v
I use an Asiair to control the scope so initial I thought that might be where the problem was (Don't know why but I though I would check). Disconnecting the AIR did not solve the problem.? The G11 was purchased 9 years ago and has worked perfectly up until now. I don't know where to start. Any suggestions ?
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Thanks
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Re: Weird clicking noise from the DEC motor
Not sure if this is the same, or not…
I had an odd noise coming from my dec motor / gear box when I first assembled my new G11 and began running it, back in March. It turned out that I had tighted the screws down too hard when I attached the motor. A half-turn to loosen the screws made the sound go away.
Good luck with yours.
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KW
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Re: Weird clicking noise from the DEC motor
I tried the sound file but couldn’t really get it to work.?
Take it off the axes and run it on a bench. ?You can do this with both motors. ?Bench run.?
Or swap it to DEC and DEC motor to Ra. ?Go check the gearbox engagement gear teeth snd Oldham coupling
I have heard a HT make a loud clicking sound. I said to owner “honestly if I take it apart it may damage it”. ?It was doing it’s job so we left it.?
If it was me id want yo know I’d take it apart but I do have the equipment for that stuff ? ?Taking small motors apart….easily ends in tears! ?For example. ?Failing to index mark end cap to housing as oi ?t goes back perfectly; or damaging the brushes ….
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They Also have tendency’s ?to lose magnetic permeability with the commutator out and need magnet keepers !
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cheers FWIW
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Brendan
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Re: Weird clicking noise from the DEC motor
On Sat, Oct 5, 2024 at 02:33 AM, Neil Allison wrote:
weird?clicking noise from the DEC motor
Hi Niel,
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Can't really hear too much from the video. The only part in the Dec train which might go bad first would be the plastic gear box. The gears themselves are plastic which can wear out over time. The part can be obtained from Losmandy on their replacement parts page. You could also try to tighten up on the motor itself by loosening the screws and turning it CCW from the end view which should seat the pinion gear to the first gearbox gear better and see if the sound goes away. While not loud, the clicks seem to be happening at a fast pace, every second or two - which would be the case of the Dec motor reversing as needed during guiding. If you do replace, remember to lube all the gear surfaces with some good grease before reassembling. As a last thought, try running the motor at a low slew speed with it off the mount which may indicate a problem with the motor itself.
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Good luck,
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John
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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
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Weird clicking noise from the DEC motor
Hi all
I have a Losmandy G11 which started making a weird?clicking noise from the DEC motor (listen to the?video).
Here is a link to a video?containing the sound. It's 68MB so I didn't think it would?be appreciated as an attachment.
It sounds worse in the video than it really is as the phone's microphone is extremely sensitive apparently. In real?life, I have to have my ear fairly close to the motor to hear it. Has anybody heard this before? Any thoughts on what the issue might be and/or how I go about fixing it?
-- Thanks and Best Regards Neil
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Ok, that makes more sense. In that case, the errors are not large at all. Time domain peak errors are important in figuring out guiding/tracking issues. RMS values and averages are valuable, but when looking for specific faults, you would want to see the large and fast excursions, as these are harder to correct, to PEC out, and to guide out.
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Regards,
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? -Paul
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On Thu, Oct 3, 2024 at 12:59 PM, HenkSB wrote:
Paul, about the peak of the gearbox that is almost 6 arc seconds in the first graph:? This does not mean that the time domain data oscillates with that amplitude.? The proper way to look at it is to integrate the power over the peak, divide it by the total power to get the fraction of RMS that the gearbox is responsible for.?
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To get an idea of what it looks like in reality (using a raw FFT spectral analysis, which is a bit crude), I zeroed out the off-peak Fourier components and inverse-FFTed it, the plot looks like this:
This is definitely significant, but it clearly does not have the 6 arc second spectral peak value for an amplitude.? Doing the same for the 76-second peak, I get this:
The RMS fraction of the 32-second peak is 0.4 and that of the 76-second peak is 0.22.? ?These values do not change much for the 3 parameter settings.? The RMS value is about 0.95 for all scenarios, so that is also not affected much by the parameter settings.? This was for RA.?
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I noticed that for DEC that the RMS values are 0.77, 0.9 and 1.1.? This could mean that DEC is affected by the parameter settings, or that the atmospheric and other environmental conditions changed.??
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Lastly, I mentioned the McLennan gearbox.? ?This is a mistake, I have the Losmandy gearbox.
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Paul, about the peak of the gearbox that is almost 6 arc seconds in the first graph:? This does not mean that the time domain data oscillates with that amplitude.? The proper way to look at it is to integrate the power over the peak, divide it by the total power to get the fraction of RMS that the gearbox is responsible for.?
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To get an idea of what it looks like in reality (using a raw FFT spectral analysis, which is a bit crude), I zeroed out the off-peak Fourier components and inverse-FFTed it, the plot looks like this:
This is definitely significant, but it clearly does not have the 6 arc second spectral peak value for an amplitude.? Doing the same for the 76-second peak, I get this:
The RMS fraction of the 32-second peak is 0.4 and that of the 76-second peak is 0.22.? ?These values do not change much for the 3 parameter settings.? The RMS value is about 0.95 for all scenarios, so that is also not affected much by the parameter settings.? This was for RA.?
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I noticed that for DEC that the RMS values are 0.77, 0.9 and 1.1.? This could mean that DEC is affected by the parameter settings, or that the atmospheric and other environmental conditions changed.??
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Lastly, I mentioned the McLennan gearbox.? ?This is a mistake, I have the Losmandy gearbox.
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Re: Light Lubrication of Losmandy RA Shaft Recommended?
Dan,?
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Suggest you review the Losmandy relube video on their YouTube channel for proper advice. They do sell a kit for cleaning and relubrication of the interior needle bearings. If you do wish to do it yourself, you can clean the bearings with alcohol and a brush, wipe clean with rag, then reapply some grease into the needles. The grease Losmandy uses at the factory is Jet-Lube Artic, while I prefer the heavier-duty Mobilgrease 28.
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Good luck,
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John
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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
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Light Lubrication of Losmandy RA Shaft Recommended?
I have an observatory on the Florida Gulf Coast, and just had to remove all equipment prior to the arrival of hurricane Helene.? I have a Titan mount, and I've had to evacuate the equipment from the dome for several prior hurricanes also.? Each time I do this, pulling the DEC head unit off the RA shaft can be difficult, even though I do not see any corrosion on the RA shaft.
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I question as to whether it would be feasible to put a very thin coat of some sort of lubrication on the RA shaft, without getting any excess on that Teflon pad.??
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Possibilities would be a thin coat of 3-in-1 oil, Teflon spray chain lube, or bicycle dry wax chain lube.? I suppose I could remove the Teflon pad when applying this, and keep it thin, so I don't get excess on the pad when re-installing the DEC head.
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I constantly run dehumidifier and A/C unit in the dome, and have not noticed corrosion on my instruments since 2015, but it is on the Gulf coast.
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The light lubrication would be to lessen the chances of corrosion, and make it easier in the future to remove the DEC head.
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My neighbor recorded a wind speed of 108 MPH as the storm came by, so evacuation was advisable.? This is at Ochlockonee Bay, FL, and the western eye wall grazed us prior to landfall in Taylor County.
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Thanks in advance.
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Dan
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Re: Does G2 L6 Improve Slewing Accuracy?
I haven't noticed much improvement in guiding. In theory it should, but my local seeing conditions might not allow me to take advantage any improvements the upgrade made. What I noticed rather immediately was that slews and plate solves were incredibly more accurate. From a warm start in the observatory, initial gotos to bright stars I use to check focusing before an imaging session lands the star in the central portion of the camera every time. This had not been the case before. The next part of my process is to go to an object in Cartes du Ciel before I begin framing in NINA. The DSO is always in the center of the fov, though not exactly the frame I want. This, to me, is incredible. It isn't a game changer, but it was a welcome improvement and well worth the small effort to update.?
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George
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Thanks Paul,
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I scaled the FFTs such that the RMS of the data is the average of the spectrum.? This is done by dividing the FFTs (in Scilab -- probably the same as Matlab) by the square root of the number of data points.? So yes, it corresponds with RMS in arc seconds, and the expectation values of the spectrum do not depend on the number of data points.
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I was using Ekos' adaptive PEC that is indeed identical to PHD2's PPEC.? I have it turned on with a period of about 4 minutes (sidereal calculations).
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I will try swapping the gear boxes but the screws feel awfully tight, and I have to be careful not to damage the screws.? Thanks for the hint.
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M31 looks great, Henk!?
What is the vertical axis scale in the spectrum plot? Arcseconds? If yes, that gearbox error seems excessive. Might be worth trying to swap gearboxes.
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You could likely fix the 32sec error if you program Gemini PEC function with 2x worm cycle.
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I believe Ekos has an adaptive PEC function, similar to PHD2's PPEC, no? Do you use it?
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Regards,
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? -Paul
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I took a look at the error spectra from the data in the log file.? There were 3 periods in the session with different guiding parameters:? camera exposure = 2,1,1 and camera delay = 1,0,1.? This resulted in average sampling intervals of 4.8, 2.9 and 3.6 seconds.? These intervals include the camera exposure + processing, pulse duration and delay for the next exposure after the control action.? The pulse duration average is mostly below 300 ms, so the sampling interval is reasonably constant.? The RA error spectra look like this:
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Each of them shows the 76 second worm bearing peak and the 32 second McLennan gearbox peak, more so with the (2,1) and (1,0) cases than with the (1,1) case.? So, an exposure of 1 second with camera delay of 1 second works best to guide out the periodic errors, although of course the samples were taken in different positions, so who knows.? Altogether it doesn't look too bad compared to the off-peak errors.? So maybe it's a matter of atmospheric conditions, polar alignment, camera noise and guiding parameters.? I have not yet touched the RA worm blocks but I did for DEC, and DEC showed no special peaks.? So, I think I can fix the worm bearing peak by re-aligning the blocks.? Not much I can do about the gearbox periodic error, I think.?
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The test image for the above spectra is below, just another M31, for the record (53x2 min with an ASI2600MC, ED127CF, flats, biases, darks).? Note that BlurXTerminator was used to correct some flaws and sharpen the stars - the focuser was a bit skewed and caused oval star shapes on the right side.? Altogether I think this system will work well.? In terms of RMS, I usually get the same numbers with my G11S/OnStep.
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First light was last night.? I replaced the battery of the Gemini after seeing many of low battery warnings - it was about 0.3V instead of 3V.? I used the polar scope for polar alignment.?
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First problem I noticed, after doing some gotos and parking back to CWD, was periodic messages on the hand controller.? Every 3 seconds there was a log message that the goto had finished and a stop sign was displayed briefly each time.? Turns out, I had set automatic meridian flip in Ekos that generated an attempt to do flips in this situation; it would not happen away from CWD.? Not a big deal, I turned it off and can turn it back on once on target.? Or leave it on but avoid parking to CWD for no good reason.
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Then, the gotos were not working.? After checking all parameters and verifying they were all fine, I restarted without Ekos just using Gemini and the gotos worked fine.? The problem was that I have to start and initialize the mount before starting Ekos.? I had noticed something similar before with my AVX running under Ekos.? Somehow with OnStep I can get away with it.? After restarting staged that way, the gotos worked fine with Ekos and I was in business.? Next time I will double-check that this is indeed the cause because I don't quite understand why starting Ekos and Gemini simultaneously would cause issues.
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The autoguider calibration curves looked very good with even zero to no backlash in DEC - I had tightened it.? Using M31 as a target, guiding error was 1" to 1.5" total RMS, about the same as what I get from OnStep and much larger than I like.? I tried all kinds of autoguider control settings but there was little difference compared to the defaults.? When shutting down, I noticed that I forgot to tighten the DEC clutch. The gotos were fine nevertheless, so I don't think it mattered much; in fact, the error was often less in DEC than in RA.? Clearly, I have some work to do and examine some logs.? Thank goodness for BlurXTerminator, it handles high RMS values quite well!
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Hey thanks John! Kind of you to notice.
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As they say, even a blind pig finds an acorn every once in a while :)?
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Brian
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I am making a small change to my AM5 to MAL. ?
Since I will mount my 90mm (only about 20 lbs) on the AM5, and I need to change the AM5 over to the G11 from time to time, I am replacing the 6” bolt with a 1” bolt (and keeping the 1/4 inch bolt). ?This will lock the ZWO 200 pier extension to the MA to MAL adapter with more than enough strength. ?I figure since the G11 is very secure with the 3 bolts into the pier head, the AM5 will be also as it uses the same 3 bolt slots. ?Faster to change mounts this way. ?Just need to remember to keep the right sized allen wrench handy.
The 6” down into the tripod really is overkill considering the weight on the AM5.
and hot dipped galvanized is best to be in contact with aluminum to minimize a galvanic rust situation in the bolt. ?But hot dipped galvanized is bigger than 1/2 inch due to the hot dipping. ?So hopefully zinc will be good enough.?
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On Wed, Sep 25, 2024 at 04:00 PM, jfmiller7 wrote:
in looking at the PE200 pier extension, there is a “silver head plate” at the bottom. I assume this is removable, so the extension sits flat on the MAL to MA adapter (with access to pier extension hole).
Jim,
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Sorry for the late reply. Yes, you remove the bottom silver adapter at the bottom of the pier extension. The adapter shape should be the same as the bottom of the AM5 itself.? I have the pier extension which is not a tube but three thick rods. You may need to check if you need only one extension - the AM5 is not very tall itself and my scope comes very close to hitting my pier. But I think you'll find the Losmandy tripod is much more solid than the lightweight carbon fiber tripod ZWO sells with their mount. So far, the AM5 has worked well for me, but the limitation is the payload spec which is not close to a G11. Apparently, the harmonic drives are not scalable, so we may never see this type of mount with a 50 - 60 pound or greater payload capacity. If your payload is getting close to 30# or more, the Losmandy mounts will carry the load.
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John
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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
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Re: High Resolution Tracking Gemini 2 Level 6...
On Thu, Sep 26, 2024 at 06:33 AM, Dnorton wrote:
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Looks like another satisfied Losmandy customer.? ?8^)??
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Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
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Congrats to our old friend Brian Valente with his recent achievement of getting a NASA APOD:
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High honors, Brian! Nice going :).
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John
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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
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I picked up a G11G on Cloudy Nights from 2015 with HT motors (non-tucked-in), HD folding tripod, Gemini-2 level 5 and polar scope, no SLW, for $2100.? The mount looks like new, it was well taken care of by the previous owner.? I upgraded the Gemini-2 to level 6, got a PicKit3, flashed the motor controllers with v3.0 and checked the 4x checkboxes.? I just tried it with Ekos, everything works beautifully.? ?I'll try to get a first light tonight.
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The previous owner loved the mount, but he had moved to a place where he had no good space to set up a telescope, so it didn't get used.? I picked it up from Arizona with a detour to visit an old friend, almost 23 hours of driving without air conditioning but well worth the drive.
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My current mount is a G11S from 2018 with OnStep.? One reason for getting the new one is to compare a standard Losmandy with servo motors with OnStep that uses steppers.? Comparing the price of Gemini II with motors with the $2100 that I paid, I think this is an excellent deal.? I can always sell it easily should I want to.?
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Another reason for getting it is to have a more "mobile" mount.? I have an observatory that is a converted lean-to shed against a wall next to the kitchen area from where I can only see the Southern skies.? I noticed that I could see most of the sky including Polaris from the patio in front of my kitchen window.? Since I don't like to move the mount in my observatory to that spot and back all the time, it is nice to have another one.? It is also handy for star parties.? I got a Telegizmo cover to keep it set up outside for New-Moon weeks.
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Paul Kanevsky
Chip Louie