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Re: Meridian Flips and NINA
On Sun, Jun 27, 2021 at 07:36 PM, Edward Plumer wrote:
Paul or others more experienced in Gemini-II.? Do you know how Gemini mounts respond to the ASCOM query "CanSetPierSide".? According to Stefan, NINA first checks this property and sets the new pier side if allowed. This is usually what causes a flip. It then issues a goto back to the same target it case this fails or is not supported. Gemini.NET reports that it supports setting Side of Pier, and will ask Gemini to perform a flip when so requested. Gemini has internal logic that determines if and when a flip is possible.?
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Re: Meridian Flips and NINA
Before weather socked in, I was doing 10min subs
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On Sun, Jun 27, 2021 at 06:57 PM, Jim Waters wrote: Edward - I have been following the discussions here and on Discord.? This does need more investigation and Gemini-II innerworkings need to be explained to the NINA dev team.? ?I haven't been having issues with my setting but I don't image past 90 sec because of light pollution.? I will try to setup some daytime imaging sessions doing 10 minute subs.? There have been meridian flip coding changes in the Nightly Builds and between 1.10 HF3 and 1.11.x so any testing should focus on the current Nightly Build. ? -- Edward |
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Re: Meridian Flips and NINA
Chatted with Stefan over on NINA Discord and explained about the issue with pausing. He pointed out that even if the mount is paused, the effective Hour Angle of the *target* to which the eventual goto is performed is still progressing and it will cross the WGL, even if the direction the scope is pointing does not. So, I no longer see how this is an explanation for MF failure without other information. Your thoughts Guilherme? Paul or others more experienced in Gemini-II.? Do you know how Gemini mounts respond to the ASCOM query "CanSetPierSide".? According to Stefan, NINA first checks this property and sets the new pier side if allowed. This is usually what causes a flip. It then issues a goto back to the same target it case this fails or is not supported. -- Edward |
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Re: Meridian Flips and NINA
Just the meridian flip trigger in the advanced sequencer and the switch in the sumple sequencer?
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On Sun, Jun 27, 2021 at 11:33 AM, Jim Waters wrote: Edward - have you used the new Smart meridian Flip yet?? How do you like it? ? -- Edward |
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Re: Changing the servo motor encoders from 256 to 512 or 1024. Any reason not to do this?
I'm not Alan...but I'll pitch in some ideas...? 240 sec is the worm period of a G11 (and half the worm period of a GM8).? {Actually 239.344 sec} The term "confounded" is used in statistics to mean when several variables can have the same effect on an outcome...so you can't tell what variable is making the effect.?? The 239 sec worm period is confounded with everything that returns to it's same position at that time: 1. The worm itself...can be bad.? Try exchanging the RA and DEC worms to see which gives the lowest PE...then keep the lower one on RA. 2. The Oldham coupler.? Ideally you want the Oldham coupler input and output shafts to be exactly in the same line.? Watch for the center white plastic part movement during worm driving...if that white plastic part is moving up and down or in and out, you should try to adjust your gearbox location (or inner drive shaft location if you have a tucked motor design)? (you may have to enlarge or slot the mounting ear holes if the older direct drive design) to minimize the movement of that center white part. 3. Transfer gears can wobble if you have a tucked motor system. Don't mesh these too tightly... have no tight point. 4. Inner transfer gear drive shaft can wobble if you have a tucked motor system.?? 5. The gearbox drive shaft final gear also rotates at the same rate as the worm. Try a different gearbox. As Alan has said, the worm period of all these mounts is very long (239 sec on a G11) and can autoguide out very nicely most of the time.? It is the faster oscillation from a bad gearbox (1/7.5 of the worm period or 32 sec on a G11), or a bad RA worm bearing ball getting pinched (~78-80 sec on a G11) that really challenge autoguiding efforts. Have fun, Michael On Sun, Jun 27, 2021, 12:16 PM pcboreland via <pcboreland=[email protected]> wrote: Alan, |
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Re: Very odd polar align issue
Ok.? Let's see what might be wrong: 1. Are your tripod legs really secure? ? ? ? ?Depending on your tripod, if it has telescoping legs, under heavy weight (depending on your scope and counterweight load), the legs can either slip (very slowly collapse!) or if the legs are not in firm (flagstone) ground, they can slip or shift the ground under them.? 2.? Your AZ is secure because you locked down your bolts.? If you did your PA with those AZ bolts loose, the act of tightening them.afterward can causeyour PA to shift!? ?For that reason, I suggest you add in 3/8 Belleville spring washers like shown in the attached photos.? The Belleville springs will give you adjustable AZ bolt pressure. 3. Further related, the AZ mount axis rotates around a central pivot point.? The pivot on these mounts is a central bolt under the mount center.? That bolt has to be loose so the AZ can pivot.? I add a heavy 3/8 Belleville washer to that to also strengthen the AZ rotation.?? 4. It was noted that your ELevation bolts might be so tight that you cannot adjust EL.? Same idea as above: using 3/8 Belleville springs on those bolts gives you adjustable pressure.?? See attached photos ...I make up special bolts and spring packages for these.? ?Contact me if interested. 5. Using stars at the pole is good but approximate.? Better is to do a Drift Align using a star at the meridian and equator after the pole star alignment.? Drift alignment is the ultimate way to perfect your PA before deep sky imaging.? PHD2 has good tools for this.? Look into them... Best, Michael On Sat, Jun 26, 2021, 10:38 AM Nick Ambrose <nick.a.ambrose@...> wrote: Making a new thread here since this is a bit different than the other one - not sure of the etiquette. |
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Yet another DIY spring loaded worm - ultra minimalist approach
I have a quite old G11 (18yrs) with a brass RA and steel DEC worm which I got for $100 w/o weights or controller. With a complete clean/lube and Gemini-II w/new motors- I've used it for about a year now with very good AP results at 1000mm fl considering its age (.5-1" guiding on calm nights with good seeing).
That is with the exception for the need to adjust the seasonal temperature sensitive worm block positions and the nightly pause to add one or two 12oz magnetic weights when going over-the-meridian (with the associated backlash / bouncing). After reading the latest attempts to solve or mitigate the issues with the legacy worm design w/o the wait or expense of buying the Losmandy upgrades, I decided to play with some ideas. While I do 3D modelling and printing, but don't have a machine shop, I am trying a super minimalist approach.? I added? ~ 1/2" long, 1/4" wide, 1/16" thick piece of rubber band inside the post hole for the outside RA and DEC worm blocks. The DEC band is centered at 90¡ã off the axis of the worm to push the worm directly toward the ring gear and the RA is centered at 45¡ã to push toward both?the ring gear and back against the worm axis (keeping pressure between the ring gear teeth and the worm). The cushioned blocks are now slightly off snug tight and the other blocks are just snug, which gives the blocks some ability to move without being loose. I will need to keep an eye on them working their way loose, but the mount seems to be behaving at least as good as it was before, with visibly improved DEC backlash. I will update this thread when I get more data on the mount's guiding behavior. While I don't expect to not need to use the weights, I am hopeful the sensitivity to temperature and over-the-meridian and backlash /bouncing is improved. |
Paul Kanevsky
Edward Plumer
Michael Herman
Greg
David Malanick