Re: G-11 Meridian Flip with ASIAir Pro
Jim-
?
Did you figure this out? I just a G11G (used). Everything is fine with my ASIAir Plus, except it does not meridian flip. I have to go to pause the Plan in ASIAir, go to Home (CWD position), then restart the plan. I works, but that means I have to be awake during the flip...that messes with my beauty sleep :)
|
Re: GM811, PHD2 and Non-Periodic RA Spikes
On Thu, Aug 29, 2024 at 06:17 AM, <kevinwalsh324@...> wrote:
Would there be any harm done in simply running the mount back and forth a bunch of times to its East and West limits on both sides of the Meridian?
This might smooth-out whatever is causing the spikes in RA. ’Work out the kinks’, so to speak, like someone doing some warm-ups and stretches before a run.
I'm sure doing this is fine but I'm not sure what you think is going to happen.
?
If there is debris somewhere in the drivetrain or there are sticky bearings due to contamination or using the wrong grease this won't do anything significantthat I can see. It won't hurt anything if the limits are set correctly for your rig but I doubt it will give any benefits either.?
?
--
Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
|
Re: GM811, PHD2 and Non-Periodic RA Spikes
Would there be any harm done in simply running the mount back and forth a bunch of times to its East and West limits on both sides of the Meridian?
This might smooth-out whatever is causing the spikes in RA. ’Work out the kinks’, so to speak, like someone doing some warm-ups and stretches before a run.
|
Re: GM811, PHD2 and Non-Periodic RA Spikes
Chip,
I keep worm?end play controlled by manually pushing the outside worm block toward the motor as hard as I can while tightening the block with my other hand. Michael Herman's paper is this one, I believe:??.? It's full of interesting information and something that I will seriously consider the next time I take everything apart. Adding a Bellvue?spring looks straightforward.
I never considered the Oldham couplers as a possible source for errors. I did replace them this spring so they are new, but not lubed.? Nevertheless I will put a little bit of SuperLube on them.??
The learning experiences?I've had with my mount remind me that this is not so much a lesson in technical, incremental improvements but rather, attempts to wrestle the beast into submission.
Paul
On Tue, Aug 27, 2024 at 06:07 PM, Paul Buckley wrote:
Chip, interesting comment.? I habitually readjust worm?block spacing outdoors every October and March (or thereabouts) because of the seasonal changes here in?WNY. I may have had this RA spiking issue all along but it was always masked by the "bigger holes in the sieve" problems, so to speak. As I've become more technically proficient and have better mastered the mount, other sources of error have fallen away or are controlled to the point that these RA spikes are next on my list of issues to resolve.??
?
Except for a few experiments I have never stalled the mount, at least not during an observing session.? I will incrementally back off the worm blocks next time the skies are clear.? My current RMS errors are generally right around 0.5" so my goal will be to keep them in that range without those occasional spikes.
?
Paul
On Tue, Aug 27, 2024 at 06:37 AM, Paul Buckley wrote:
UPDATE on my RA spike issue:? I swapped RA and DEC motors but the spikes stayed with RA, so I've ruled out the motors.? There are no more clear nights for the time being, but my next experiment will be to back off the RA worm blocks a couple hundredths of a millimeter at a time to see what that does.? I'm?pretty?confident that it will make a difference, just not sure about the resulting backlash.? My last resort will be to bite the bullet and degrease/relube the worm/ring gears and use John Kmetz' suggested in house HGM lubricant.? I'm currently using Stalube?Synthetic Brake & Caliper Grease (Moly?+ PTFE?+ graphite).
?
Paul
?
?
Wait, before you bother to strip the mount think about what the mount is doing as it gets cold acclimated.? Your classic Losmandy 2-piece worm drive system mount will never have as low backlash as the newer spring loaded OPWs. This is a fact and nothing is going to change that.? That said backlash on the classic Losmandy drivetrains is your friend in the dark especially as the night air gets colder and the winter moves in.? The thing to know is that with the classic drivetrain Losmandy GM8 and G11 mounts backlash shrinks as the air temp drops. If your mount has minimal backlash in a warm room it will stall once it shrinks in cold air. Ideally you should set your backlash up on a fully cold acclimated mount. Once it warms up it will seem to have a ton of backlash but that's okay because you don't use it to capture images when it is warm. There is no grease made that can overcome the sliding friction of a worm with no backlash with the low level of torque the Gemini drive systems produces. You MUST have some backlash or stall the drivetrain.?
?
--
Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
?
?
?
With an average PE in the 0.5" RMS range and lower the spikes are not likely from worm to worm gear backlash. Have you checked your worm axial end play? This one is easily resolved in the old 2-piece worm blocks by adding Bellvue disc springs which minimize worm shaft end play and also prevents the bearing balls from.causimg the start / stop bumps in tracking error. Michel Herman and I worked on this and he wrote a nice note about the problem, it's here someplace. Just Google Michael Herman and how to improve Losmandy mount or something .?
?
This issue could also be contamination in the drivetrain or axel bearings, it could be anywhere. Servo pinion, hearboxes, loose or missing set screws to Oldham couplers (there should be 2 per coupler), Oldham parts, worm or worm gear faces etc.?
?
It sounds wacky but have you lubed your Oldham couplers to see if this has any impact??
?
Being desperate early in my Losmandy ownership more than a few moons ago discovered that using heavy grease on the Oldham couplers can sometimes have a positive effect on PE smoothness. I don't know if they were just dirty, worn out, had some kind of a hitch or damage in the plastic sliding piece or just made them move easier smoother or what but it helped my PE curve. I have only done it twice and only saw an improvement on one mount.
?
I replaced the Oldhams on that GM8 mount and it was not an issue anymore but then I sold it. I still put a tiny toothpick daub of Superlube with Teflon on the Oldhams after cleaning them when I reassemble Losmandy mounts. Just sort of a religious thing as I can't proove one way or another if it really works or not LOL.?
?
--
Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
|
Re: GM811, PHD2 and Non-Periodic RA Spikes
On Tue, Aug 27, 2024 at 06:07 PM, Paul Buckley wrote:
Chip, interesting comment.? I habitually readjust worm?block spacing outdoors every October and March (or thereabouts) because of the seasonal changes here in?WNY. I may have had this RA spiking issue all along but it was always masked by the "bigger holes in the sieve" problems, so to speak. As I've become more technically proficient and have better mastered the mount, other sources of error have fallen away or are controlled to the point that these RA spikes are next on my list of issues to resolve.??
?
Except for a few experiments I have never stalled the mount, at least not during an observing session.? I will incrementally back off the worm blocks next time the skies are clear.? My current RMS errors are generally right around 0.5" so my goal will be to keep them in that range without those occasional spikes.
?
Paul
On Tue, Aug 27, 2024 at 06:37 AM, Paul Buckley wrote:
UPDATE on my RA spike issue:? I swapped RA and DEC motors but the spikes stayed with RA, so I've ruled out the motors.? There are no more clear nights for the time being, but my next experiment will be to back off the RA worm blocks a couple hundredths of a millimeter at a time to see what that does.? I'm?pretty?confident that it will make a difference, just not sure about the resulting backlash.? My last resort will be to bite the bullet and degrease/relube the worm/ring gears and use John Kmetz' suggested in house HGM lubricant.? I'm currently using Stalube?Synthetic Brake & Caliper Grease (Moly?+ PTFE?+ graphite).
?
Paul
?
?
Wait, before you bother to strip the mount think about what the mount is doing as it gets cold acclimated.? Your classic Losmandy 2-piece worm drive system mount will never have as low backlash as the newer spring loaded OPWs. This is a fact and nothing is going to change that.? That said backlash on the classic Losmandy drivetrains is your friend in the dark especially as the night air gets colder and the winter moves in.? The thing to know is that with the classic drivetrain Losmandy GM8 and G11 mounts backlash shrinks as the air temp drops. If your mount has minimal backlash in a warm room it will stall once it shrinks in cold air. Ideally you should set your backlash up on a fully cold acclimated mount. Once it warms up it will seem to have a ton of backlash but that's okay because you don't use it to capture images when it is warm. There is no grease made that can overcome the sliding friction of a worm with no backlash with the low level of torque the Gemini drive systems produces. You MUST have some backlash or stall the drivetrain.?
?
--
Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
?
?
?
With an average PE in the 0.5" RMS range and lower the spikes are not likely from worm to worm gear backlash. Have you checked your worm axial end play? This one is easily resolved in the old 2-piece worm blocks by adding Bellvue disc springs which minimize worm shaft end play and also prevents the bearing balls from.causimg the start / stop bumps in tracking error. Michel Herman and I worked on this and he wrote a nice note about the problem, it's here someplace. Just Google Michael Herman and how to improve Losmandy mount or something like.it.?
?
This issue could also be contamination in the drivetrain or axel bearings, it could be anywhere. Servo pinion, hearboxes, loose or missing set screws to Oldham couplers (there should be 2 per coupler), Oldham parts, worm or worm gear faces etc.?
?
It sounds wacky but have you lubed your Oldham couplers to see if this has any impact??
?
Being desperate early in my Losmandy ownership more than a few moons ago discovered that using heavy grease on the Oldham couplers can sometimes have a positive effect on PE smoothness. I don't know if they were just dirty, worn out, had some kind of a hitch or damage in the plastic sliding piece or just made them move easier smoother or what but it helped my PE curve. I have only done it twice and only saw an improvement on one mount.
?
I replaced the Oldhams on that GM8 mount and it was not an issue anymore but then I sold it. I still put a tiny toothpick daub of Superlube with Teflon on the Oldhams after cleaning them when I reassemble Losmandy mounts. Just sort of a religious thing as I can't proove one way or another if it really works or not LOL.?
?
--
Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
|
Re: GM811, PHD2 and Non-Periodic RA Spikes
On Fri, Aug 23, 2024 at 04:28 PM, Paul Buckley wrote:
Celestron 9.25"Edge HD with an OAG
Observing the guiding, one might contend that it resembles the primary mirror support. An Off-Axis Guider (OAG) would detect when starting friction permits a minor deviation in the optical path.? However, correcting this deviation takes time, resulting in our rapid observable motion followed by a gradual adjustment. This movement is somewhat evident in the declination too, manifesting as a shift in one direction, followed by a realignment, but without the oscillation characteristic of a windup effect.
?
Slippage appears to be random in occurrence. Considering the duration, it only disrupts the maximum peak. It's also unlikely to be evident in an exposure as others noted. ?Could be the primary or the secondary and behave this way if true.
?
?
?
?
?
|
Re: GM811, PHD2 and Non-Periodic RA Spikes
On Tue, Aug 27, 2024 at 09:37 AM, Paul Buckley wrote:
UPDATE on my RA spike issue:? I swapped RA and DEC motors but the spikes stayed with RA, so I've ruled out the motors.? There are no more clear nights for the time being, but my next experiment will be to back off the RA worm blocks a couple hundredths of a millimeter at a time to see what that does.? I'm?pretty?confident that it will make a difference, just not sure about the resulting backlash.? My last resort will be to bite the bullet and degrease/relube the worm/ring gears and use John Kmetz' suggested in house HGM lubricant.? I'm currently using Stalube?Synthetic Brake & Caliper Grease (Moly?+ PTFE?+ graphite).
Hi Paul,
?
The caliper greases work but start to get very tacky over time as they lose their solvent content. Please send me a PM and I can send you a sampler of MP-50 at cost (the smallest can online is ~$100). The reported chatter doesn't occur at regular intervals, just when spring tension lets go. If you take the mount apart again, you may wish to replace the worm bearings, thrust bearings and needle bearings too if you are so motivated. But you will need a bearing puller to get the needle bearings out, which I can also loan to you. It sounds like something is catching and grabbing - you'll just have to go through the process of elimination. I have a parts list as well.
?
Regards,
?
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
|
Re: GM811, PHD2 and Non-Periodic RA Spikes
Chip, interesting comment.? I habitually readjust worm?block spacing outdoors every October and March (or thereabouts) because of the seasonal changes here in?WNY. I may have had this RA spiking issue all along but it was always masked by the "bigger holes in the sieve" problems, so to speak. As I've become more technically proficient and have better mastered the mount, other sources of error have fallen away or are controlled to the point that these RA spikes are next on my list of issues to resolve.??
Except for a few experiments I have never stalled the mount, at least not during an observing session.? I will incrementally back off the worm blocks next time the skies are clear.? My current RMS errors are generally right around 0.5" so my goal will be to keep them in that range without those occasional spikes.
Paul
On Tue, Aug 27, 2024 at 06:37 AM, Paul Buckley wrote:
UPDATE on my RA spike issue:? I swapped RA and DEC motors but the spikes stayed with RA, so I've ruled out the motors.? There are no more clear nights for the time being, but my next experiment will be to back off the RA worm blocks a couple hundredths of a millimeter at a time to see what that does.? I'm?pretty?confident that it will make a difference, just not sure about the resulting backlash.? My last resort will be to bite the bullet and degrease/relube the worm/ring gears and use John Kmetz' suggested in house HGM lubricant.? I'm currently using Stalube?Synthetic Brake & Caliper Grease (Moly?+ PTFE?+ graphite).
?
Paul
?
?
Wait, before you bother to strip the mount think about what the mount is doing as it gets cold acclimated.? Your classic Losmandy 2-piece worm drive system mount will never have as low backlash as the newer spring loaded OPWs. This is a fact and nothing is going to change that.? That said backlash on the classic Losmandy drivetrains is your friend in the dark especially as the night air gets colder and the winter moves in.? The thing to know is that with the classic drivetrain Losmandy GM8 and G11 mounts backlash shrinks as the air temp drops. If your mount has minimal backlash in a warm room it will stall once it shrinks in cold air. Ideally you should set your backlash up on a fully cold acclimated mount. Once it warms up it will seem to have a ton of backlash but that's okay because you don't use it to capture images when it is warm. There is no grease made that can overcome the sliding friction of a worm with no backlash with the low level of torque the Gemini drive systems produces. You MUST have some backlash or stall the drivetrain.?
?
--
Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
|
Re: GM811, PHD2 and Non-Periodic RA Spikes
On Tue, Aug 27, 2024 at 06:37 AM, Paul Buckley wrote:
UPDATE on my RA spike issue:? I swapped RA and DEC motors but the spikes stayed with RA, so I've ruled out the motors.? There are no more clear nights for the time being, but my next experiment will be to back off the RA worm blocks a couple hundredths of a millimeter at a time to see what that does.? I'm?pretty?confident that it will make a difference, just not sure about the resulting backlash.? My last resort will be to bite the bullet and degrease/relube the worm/ring gears and use John Kmetz' suggested in house HGM lubricant.? I'm currently using Stalube?Synthetic Brake & Caliper Grease (Moly?+ PTFE?+ graphite).
?
Paul
?
?
Wait, before you bother to strip the mount think about what the mount is doing as it gets cold acclimated.? Your classic Losmandy 2-piece worm drive system mount will never have as low backlash as the newer spring loaded OPWs. This is a fact and nothing is going to change that.? That said backlash on the classic Losmandy drivetrains is your friend in the dark especially as the night air gets colder and the winter moves in.? The thing to know is that with the classic drivetrain Losmandy GM8 and G11 mounts backlash shrinks as the air temp drops. If your mount has minimal backlash in a warm room it will stall once it shrinks in cold air. Ideally you should set your backlash up on a fully cold acclimated mount. Once it warms up it will seem to have a ton of backlash but that's okay because you don't use it to capture images when it is warm. There is no grease made that can overcome the sliding friction of a worm with no backlash with the low level of torque the Gemini drive systems produces. You MUST have some backlash or stall the drivetrain.?
?
--
Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
|
On Mon, Aug 26, 2024 at 02:57 PM, Ed Harp wrote:
On Mon, Aug 26, 2024 at 02:05 PM, Chip Louie wrote:
I LOVE my Berlebach Planet!? But I wouldn't want to ruin the black finish by rotating the MA on top to get your mount aligned! You can cut a circle out of a thin sheet of polyethylene to protect the base and make rotation easier.?
I actually disassembled the tripod and machined the top to provide a relatively precise hole for the 1/2" bolt and a smooth flat surface for the Losmandy base plate to rest on. The anodization on the Losmandy base plate will prevent any galling. I happen to have a cnc machine shop in my garage.?
?
Level wise, I do have precision levels. Not sure how I would use them here. I think I get the idea from you two and I really appreciate your advice.
?
And speaking of modeling, I wondered if my mount just needed breaking in a bit when I was having issues with it so I used TheSkyX to run several 160+ target TPoint models. About an hour or slewing each time. It seemed to do well and I seemed to be getting good tracking. I won't be using that regularly.
?
I also want to try PemPro.
?
Hi!
?
You skimmed the top face of the Berlebach tripod head? Wow, you are brave. Having a machine shop you could also make a large diameter ball bearing turntable to make rotating the fully loaded mount easy to rotate during PA but I like the simpler, cheap slippery plastic disc route. Might as well have a slick smooth surface to rotate that mini pier head on.?
?
The idea is to use the precision levels to ensure that the built-in bubbles on the Losmandy base are true. If not you have to dig them out along with the white caulk and clean off the milled seats of any debris to seat the new vials in full contact with the seats. I have checked a few and they have all been true when checked against the base flange seating face so I trust the seats to be parallel with the base seating surface. Invert the base, seat the new vials and caulk them in place and let it cure fully before touching your work. 24 hours later off you go with known good bubbles in the base.??
?
Regarding breaking in the drivetrain, others with new mounts have commented on this and it seems sometimes running them in for a few hours improves them as far as PE and smoothness. Some have not seen this but I think they may not have run them in long enough to see it. I bought a new GM8G from Losmandy in the second year of Covid and just set the mount to exercising at a slewing speed for a week one direction then the other on both axes. But in all honestly that new GM8G worked very well from the get go even before I had it doing 360's for a week straight LOL. So in my case it didn't seem to work either. Who know???
?
--
Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
|
Re: GM811, PHD2 and Non-Periodic RA Spikes
UPDATE on my RA spike issue:? I swapped RA and DEC motors but the spikes stayed with RA, so I've ruled out the motors.? There are no more clear nights for the time being, but my next experiment will be to back off the RA worm blocks a couple hundredths of a millimeter at a time to see what that does.? I'm?pretty?confident that it will make a difference, just not sure about the resulting backlash.? My last resort will be to bite the bullet and degrease/relube the worm/ring gears and use John Kmetz' suggested in house HGM lubricant.? I'm currently using Stalube?Synthetic Brake & Caliper Grease (Moly?+ PTFE?+ graphite).
Paul
On Sun, Aug 25, 2024 at 11:00?AM Paul Buckley via <paulbuckley14059= [email protected]> wrote: All,
After an additional night?of observation and a slight tightening of the RA clutch, the random spikes are still there, not frequent but consistent.? I'll check the lubricant that I used (actually two lubricants, a molybdenum based lube for the ring/worm gears and a different one for the needle bearings - I don't have access to them right now but will check later to get their?exact names. I know that my choices were carefully selected based on the Losmandy group's recommendations and I was satisfied with the research that was done.? As for my worm gear, it's a pre-spring-loaded worm so no "backing off" in that suggested manner, but I could increase the gap slightly between the worm's support posts and the mount - I think that would be equivalent, and it will certainly trade off gear mesh for backlash.? I currently have the RA standoffs gapped to 0.76mm for any of you that?also do this.? Not sure that increasing the gap is going to be a good thing during a meridian flip, though, as more backlash will amount to slop during that transition.? But it's certainly worth a try.??
As per John Kmetz' suggestion that worm gear "chatter" could cause this:? Wouldn't that result in a periodic error?? It's the aperiodicity that has me hunting for and understanding root cause.
I'll swap the gear motors tonight to see what happens.?
All of this problem-solving would normally take me weeks to resolve, but Western New York is enjoying an unheard-of string of 5 clear nights in a row, so with each night I can tweak something to see what effect it might have on tracking.
Paul ?
On Fri, Aug 23, 2024 at 04:28 PM, Paul Buckley wrote:
All gearing and bearings have been thoroughly cleaned but I suspect something in the RA train is binding up, then suddenly releasing.? I keep the clutches relatively loose.? No real differences between East and West guiding.? Alternatively, maybe it's the power supply (but then, why only RA)?? Or a corrupted signal from PHD2? One of these days I'll try swapping motors but because tracking is generally really good I don't want to fool around with the drive train until I absolutely have to.
?
Regardless, I should be grateful - I typically get at least 9 good images out of every 10 - but those spikes just bug me because I can't determine root cause.? Have any of you dealt with this in the past, and if so, I'll take as many recommendations as I can get.
?
?
Paul
Paul,
?
This is not normal even for a long local length - I have the same scope. I take it you are seeing this over multiple nights, not just on one occasional with passing clouds or variable seeing. When you cleaned and lubed your bearings did you use the HGM inhouse lubricant - the Jet-Lube MP-50? Few other greases have the same extreme pressure additive composition, and your ring and worm contact could be chattering - building up tension and then releasing. Since your RA spikes are all in the same direction, this could be the case as the worm motion always pushes the mount westward. Your worm spring tension could also be set a bit too tight and the smooth sliding between the gears is not happening. Perhaps try backing off a bit without creating too much backlash.?
?
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
|
Re: G11 guiding perfect until last night
Sorry for the late response. Cloudy until tonight. Guiding is not as bad as before, but not better. Ranges from .8-1.2.
?
Going to replace clutch pads and wavy washer. Maybe I should clean the worm gears? Its been a couple years. I could take them out and clean them well.?
?
Want to get this sorted before the BFSP this sept!
--
Gear:
Mount:?Losmandy G11G Gemini 2 Level 6, Star Adventurer Pro
Optics:?Redcat 51 V2, Canon EOS 18-135mm Zoom Lens
Camera:?ZWOASI 533 MC Pro, Canon EOS 80D (Stock)
Guide Camera:?ZWOASI 120mm
Guide Scope:?ZWO 30mm f/4
Brain:?PrimaLuceLab Eagle 4
Filters:?Optolong L-Ultimate, Astromania Luminance Filter
|
On Mon, Aug 26, 2024 at 02:05 PM, Chip Louie wrote:
I LOVE my Berlebach Planet!? But I wouldn't want to ruin the black finish by rotating the MA on top to get your mount aligned! You can cut a circle out of a thin sheet of polyethylene to protect the base and make rotation easier.?
I actually disassembled the tripod and machined the top to provide a relatively precise hole for the 1/2" bolt and a smooth flat surface for the Losmandy base plate to rest on. The anodization on the Losmandy base plate will prevent any galling. I happen to have a cnc machine shop in my garage.?
?
Level wise, I do have precision levels. Not sure how I would use them here. I think I get the idea from you two and I really appreciate your advice.
?
And speaking of modeling, I wondered if my mount just needed breaking in a bit when I was having issues with it so I used TheSkyX to run several 160+ target TPoint models. About an hour or slewing each time. It seemed to do well and I seemed to be getting good tracking. I won't be using that regularly.
?
I also want to try PemPro.
|
On Sun, Aug 25, 2024 at 07:04 AM, Ed Harp wrote:
I appreciate your help.?
?
So by spirit level, I would guess you mean the "CWD" position the mount knows after a cold start. I've gotten to doing things this way: set up the mount and ota, balance then level the mount base spirit levels, then the two in the RA and dec, then cold start the mount. I think of this as "home" for this mount.
?
I am happy this mount worked out. It was frustrating at first. I wanted something made in this way (here, small company) that I could use with the air sometimes and finally after a bit of fuss (maybe a bad motor) I get very good guiding and reliable results.
?
I like the tripod attachment design enough to make it my standard for all of my mounts and have scared up adapters where needed and adapted a Berlebach tripod to this as well. I still use the heavy Losamandy tripod, but it's a beast. You can see a large black steel knob under the tripod top plate. The one flaw I see in the Losmandy tripod design is you cannot roughly rotate the mount. I am used to having this with other mounts. So the Losmandy base plate is attached to the Berlebach with a big 1/2" bolt so that I can rotate the mount a bit if find I am off by say 5 degrees when I go to polar align. Mechanically I am fairly certain it will be reliable.
?
?
I LOVE my Berlebach Planet!? But I wouldn't want to ruin the black finish by rotating the MA on top to get your mount aligned! You can cut a circle out of a thin sheet of polyethylene to protect the base and make rotation easier.?
?
--
Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
|
On Mon, Aug 26, 2024 at 08:05 AM, WayBack wrote:
On Sun, Aug 25, 2024 at 10:04 AM, Ed Harp wrote:
by spirit level, I would guess you mean the "CWD"
Yes, just some best practice thoughts. ?Aligning the four G11 mount spirit levels sets the mount into a mechanical position that corresponds with the initial Gemini-2 encoder position. ?The starting physical orientation of CWD and the corresponding controller state, a Cold or Warm Start, are synchronized through the encoder values. ?The simplest method involves setting the mount to CWD while powered off, and once Gemini-2 is powered on and passes the Cold Start, tracking begins. Other startup sequences just need to consider the end goal. ASIAIR expects the mount to be operational, similar to other controlled hardware, upon APP connection. If the startup process includes parking the mount, unpark afterwards for ASIAIR. Should the mount require Asmuth rotation for Polar Alignment, it now remain level to maintain accuracy with the encoders. Eventually, the mount will slew to the first bright star for sky alignment, which relies on the precision of CWD. Any movement disrupting the CWD's alignment with the encoders necessitates a return to the leveling process.? It's documented but seems to get lost in the details at times.
??
On the Meridian Filp, that was about a behavior you noted.? The type of OTA and mount set up influences the use.? Scott's enhancements enable the mount to track for hours past the Meridian with the appropriate OTA, which can sometimes eliminate the need for a Meridian Flip.??While the behavior that ASIAIR uses, a Go-To depends on the characteristics of the mount.? If Gemini-2 has two positions it can reach a target, it always does a Go-To to the closest position. ?This can cause the topics to become interwoven.
?
This involves the Limits.? As targets move across the sky, they also traverse over and past the mount's limit points. ?When using a Go-To function for a target on the West Side, ASIAIR requires the target to drift to a position accessible only from the East Side to perform a Meridian Flip. This position on the East Side becomes reachable only when the target moves beyond the EAST Limit and the start of the WGL Limit (the WEST minus WGL position). Both conditions are necessary for the flip.
?
These criteria subsequently affect the limit parameters. If the OTA permits shooting beyond the Meridian, keep the ASIAR delay parameters at zero; it's all about the limits. If the OTA makes contact at or before the Meridian, then delays are necessary to meet the criteria. However, if your OTA target can bypass a Meridian Flip by continuing to track past the Meridian, then disabling it is another excellent option.
?
This can also occur with equipment like a long refractor, where the camera cannot make contact at the northern leg latitudes. In such cases, with relaxed limits and exercising caution it’s possible to track through the meridian too.
?
Doug
?
The Gemini CWD position is simply whatever servo position values are found when Gemini wakes up. A Gemini's initial sky model on boot up always thinks the mount RA axis is perfectly aligned with the NCP, the DEC axis is perpendicular to the RA axis and that the DEC's saddle position is @ 90 degrees. This is why unless the mount is very well polar aligned Gemini's initial GOTOs can be off by widely varying degrees all other setting being correct.? While it is not critical to have a level mount before polar aligning it makes polar alignment much faster and smoother which makes initial GOTOs more accurate which results in smaller correction values to the default sky model.? ?
?
You can save some setup time by having previously set accurate CWD marks on the RA and carefully setting the DEC axis setting circles to 90 degrees and locking them in using the set screws in the DEC setting circle ring. With these marks established you use the built bubble levels in the mount base to level the mount and then set the mount to the premarked positions on the RA and set DEC to 90 using the setting circle ring and etched indicator. No need to go through the bubble level routine on the RA and DEC axes to establish a true CWD before powering up Gemini as it has already been set by using your preset marks.??
?
BTW, never trust the bubble levels on any mount even a Losmandy mount unless you have verified them with a known good digital level or precision bubble level. I have had to replace several bubble levels in used Losmandy mounts I bought or repaired because the vials were no longer properly seated.?
?
To be clear there are no encoders or position switches on Losmandy mount axes or worms. There are encoders integrated with DC motor axels which allow them to be used as servos but these are not normally used by software other than Gemini. This is not to say servo motor position data cannot be used by third party apps.??
?
--
Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
|
On Sun, Aug 25, 2024 at 10:04 AM, Ed Harp wrote:
by spirit level, I would guess you mean the "CWD"
Yes, just some best practice thoughts. ?Aligning the four G11 mount spirit levels sets the mount into a mechanical position that corresponds with the initial Gemini-2 encoder position. ?The starting physical orientation of CWD and the corresponding controller state, a Cold or Warm Start, are synchronized through the encoder values. ?The simplest method involves setting the mount to CWD while powered off, and once Gemini-2 is powered on and passes the Cold Start, tracking begins. Other startup sequences just need to consider the end goal. ASIAIR expects the mount to be operational, similar to other controlled hardware, upon APP connection. If the startup process includes parking the mount, unpark afterwards for ASIAIR. Should the mount require Asmuth rotation for Polar Alignment, it now remain level to maintain accuracy with the encoders. Eventually, the mount will slew to the first bright star for sky alignment, which relies on the precision of CWD. Any movement disrupting the CWD's alignment with the encoders necessitates a return to the leveling process.? It's documented but seems to get lost in the details at times.
??
On the Meridian Filp, that was about a behavior you noted.? The type of OTA and mount set up influences the use.? Scott's enhancements enable the mount to track for hours past the Meridian with the appropriate OTA, which can sometimes eliminate the need for a Meridian Flip.??While the behavior that ASIAIR uses, a Go-To depends on the characteristics of the mount.? If Gemini-2 has two positions it can reach a target, it always does a Go-To to the closest position. ?This can cause the topics to become interwoven.
?
This involves the Limits.? As targets move across the sky, they also traverse over and past the mount's limit points. ?When using a Go-To function for a target on the West Side, ASIAIR requires the target to drift to a position accessible only from the East Side to perform a Meridian Flip. This position on the East Side becomes reachable only when the target moves beyond the EAST Limit and the start of the WGL Limit (the WEST minus WGL position). Both conditions are necessary for the flip.
?
These criteria subsequently affect the limit parameters. If the OTA permits shooting beyond the Meridian, keep the ASIAR delay parameters at zero; it's all about the limits. If the OTA makes contact at or before the Meridian, then delays are necessary to meet the criteria. However, if your OTA target can bypass a Meridian Flip by continuing to track past the Meridian, then disabling it is another excellent option.
?
This can also occur with equipment like a long refractor, where the camera cannot make contact at the northern leg latitudes. In such cases, with relaxed limits and exercising caution it’s possible to track through the meridian too.
?
Doug
|
Re: New G11 + ASIair guiding issues
On Mon, Aug 19, 2024 at 08:19 PM, BBasiaga wrote:
I'm curious if there has been any further progress here?? It does looknlikenits way obershooting Dec, possibly due to backlash over compensation.?
?
Brian
?
?
Sorry that I missed your reply. I appreciate your thinking of me.
?
At this point I am able to guide this mount at 0.40" or better reliably. Using PHD2 or an ASIair. I am not completely sure what made the difference, but these are the things I tried.
?
- Exorcised all of the demons that were my fault. I wasn't getting particularly good balance in RA because the G11's bearings are a bit sticky. I fixed this by lowering the altitude to parallel with the ground. I also had an issue with walking around fussing over things on my concrete patio, not realizing that my shifting weight was enough to affect the mount. Not sure if it was vibration or perhaps the pad moves slightly. Also came up with a good way to arrange the cables so they are not an issue.
- I was concerned that something could be up with the DEC worm, so I swapped the two motors and then the wild spikes happened in RA, not DEC. I ordered a new motor from Losmandy who would of course refund me if I prove the motor an issue. But I haven't re-mounted the motor I replaced in order to test this. I don't mind paying for the motor to be honest.
- Someone mentioned the cables, so I bought another set of those. Pretty sure whey were not an issue.
- Posted on the PHD2 Google group and got some advice from the people there. I am fairly new to PHD2 and serious astrophotography in general, so there was a bit of a learning curve there.
- Optical train issues. I fussed over everything but the same exact gear did not have these issues on any of five other mounts by three other brands. I never ran into guiding problems beyond bad seeing. I have guided a 28 pound 130mm refractor at 0.18" in both axis on an AM5 mounted on a Berlebach tripod. So I think I'm good in this regard.
- Guiding cameras and scopes. I have tried many of them. Six cameras and at least that many guide scopes. At this point I use a RedCat51, a small Askar astrograph and Stellarvue guide scopes. All for image quality as well as a decent focuser, etc. I have guide cameras with pixel sizes from 2.9 up to 5.86. Most of the scopes I use are 180mm or longer.
- I tried OAGs but I am not crazy about them yet. The shadow the prism can make annoys me. I will try again. I tend to avoid calibration frames where I can. I have not tried ZWO's larger OAG yet but I do have one.
I am pleased this mount worked out. I was attracted to it due to how it's made (small company, here) and less complexity than my Paramount MYT, love it as I do. And being able to run it with the ASIair when I want a simple set up.
|
Re: GM811, PHD2 and Non-Periodic RA Spikes
All,
After an additional night?of observation and a slight tightening of the RA clutch, the random spikes are still there, not frequent but consistent.? I'll check the lubricant that I used (actually two lubricants, a molybdenum based lube for the ring/worm gears and a different one for the needle bearings - I don't have access to them right now but will check later to get their?exact names. I know that my choices were carefully selected based on the Losmandy group's recommendations and I was satisfied with the research that was done.? As for my worm gear, it's a pre-spring-loaded worm so no "backing off" in that suggested manner, but I could increase the gap slightly between the worm's support posts and the mount - I think that would be equivalent, and it will certainly trade off gear mesh for backlash.? I currently have the RA standoffs gapped to 0.76mm for any of you that?also do this.? Not sure that increasing the gap is going to be a good thing during a meridian flip, though, as more backlash will amount to slop during that transition.? But it's certainly worth a try.??
As per John Kmetz' suggestion that worm gear "chatter" could cause this:? Wouldn't that result in a periodic error?? It's the aperiodicity that has me hunting for and understanding root cause.
I'll swap the gear motors tonight to see what happens.?
All of this problem-solving would normally take me weeks to resolve, but Western New York is enjoying an unheard-of string of 5 clear nights in a row, so with each night I can tweak something to see what effect it might have on tracking.
Paul ?
On Fri, Aug 23, 2024 at 04:28 PM, Paul Buckley wrote:
All gearing and bearings have been thoroughly cleaned but I suspect something in the RA train is binding up, then suddenly releasing.? I keep the clutches relatively loose.? No real differences between East and West guiding.? Alternatively, maybe it's the power supply (but then, why only RA)?? Or a corrupted signal from PHD2? One of these days I'll try swapping motors but because tracking is generally really good I don't want to fool around with the drive train until I absolutely have to.
?
Regardless, I should be grateful - I typically get at least 9 good images out of every 10 - but those spikes just bug me because I can't determine root cause.? Have any of you dealt with this in the past, and if so, I'll take as many recommendations as I can get.
?
?
Paul
Paul,
?
This is not normal even for a long local length - I have the same scope. I take it you are seeing this over multiple nights, not just on one occasional with passing clouds or variable seeing. When you cleaned and lubed your bearings did you use the HGM inhouse lubricant - the Jet-Lube MP-50? Few other greases have the same extreme pressure additive composition, and your ring and worm contact could be chattering - building up tension and then releasing. Since your RA spikes are all in the same direction, this could be the case as the worm motion always pushes the mount westward. Your worm spring tension could also be set a bit too tight and the smooth sliding between the gears is not happening. Perhaps try backing off a bit without creating too much backlash.?
?
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 Sat, Aug 24, 2024 at 08:22 AM, WayBack wrote:
Indeed, another consideration is that ASIAIR calculates the meridian position using the model-adjusted clock, whereas Gemini-2 gauges the limit's midpoint via the spirit level's state. Maintaining minor model time adjustments in Right Ascension (RA) helps keep the Limit points precise. As the Go-To Slew must occur reliably within the WGL.? Narrowly setting limit points requires an accurate level state. And the mechanics of long OTAs don’t allow wide settings.?
I appreciate your help.?
?
So by spirit level, I would guess you mean the "CWD" position the mount knows after a cold start. I've gotten to doing things this way: set up the mount and ota, balance then level the mount base spirit levels, then the two in the RA and dec, then cold start the mount. I think of this as "home" for this mount.
?
I am happy this mount worked out. It was frustrating at first. I wanted something made in this way (here, small company) that I could use with the air sometimes and finally after a bit of fuss (maybe a bad motor) I get very good guiding and reliable results.
?
I like the tripod attachment design enough to make it my standard for all of my mounts and have scared up adapters where needed and adapted a Berlebach tripod to this as well. I still use the heavy Losamandy tripod, but it's a beast. You can see a large black steel knob under the tripod top plate. The one flaw I see in the Losmandy tripod design is you cannot roughly rotate the mount. I am used to having this with other mounts. So the Losmandy base plate is attached to the Berlebach with a big 1/2" bolt so that I can rotate the mount a bit if find I am off by say 5 degrees when I go to polar align. Mechanically I am fairly certain it will be reliable.
?
|
Asi Air sets only a minutes BEFORE meridian to pause imaging.? Minimum value is 0.? You can't make it go past the meridian before pausing.?
?
You then need to set your Minutes After delay to make sure it clears your Gemini limits, so when the air commands a go to it does the thing you want it to.?
?
Brian
|
Chip Louie
Ed Harp