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Re: Inaccurate pointing after 4 star model building

 

On Fri, Jan 31, 2025 at 09:11 PM, Russ Gartz wrote:
Hi, Folks,
I have a Losmandy GM8G using the Gemini II with the latest firmware update. I am using the polar scope and drift alignment only.
After a 4 star model building, I instructed the Gemini II to point to M42.? However, the pointing was off by about 2 degrees. The only thing I can think of is that all of the stars I used in the model building were in the northern celestial hemisphere and M42 is in the southern celestial hemisphere. Am I correct or am I doing something wrong? Any feedback would be appreciated.
My procedure is to use the polar scope for initial polar alignment, then do a drift alignment. After that I turn off the mount, go back to pointing North/counterweight down position, turn the mount on again and do the model building. I am manually entering in my position and time.?
By the way, does anyone have a good reference for drift alignment technique? Any ideas would be appreciated.
Best Wishes and clear skies,
Russ
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Once an object is centered does the object remain in the FOV?? For how long?? If not depending on how the error manifests there is likely a polar alignment error and/or configuration data error.??
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If the mount keeps objects well centered and your initial GOTO is off this tells you the mount type and model gearing is correct and your PA is okay but the data being used to calculate the new position to GOTO are incorrect.? This could be the assumed initial position Gemini is using is incorrect which includes CWD position, GPS coordinates and UTC settings.?
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But if you are building a model and you are off by 2 degrees as Paul suggests you may have a star identification issue.? This assumes your mount is mechanically 100% and Gemini has correct configuration data.??
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Just have to keep isolating the issue and working it backwards.?
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--

Chip Louie Chief Daydreamer Imagination Hardware?

Astrospheric - South Pasadena, CA?
Re: Inaccurate pointing after 4 star model building

 

Russ,

Please clarify a few things.

Is this a new mount to you? Is this something that has just started? Are your alignment stars spread out across the sky or close together? Are you selecting alignment and not synchronise?

-- Paul
Re: Inaccurate pointing after 4 star model building

 

On Sat, Feb 1, 2025 at 12:11 AM, Russ Gartz wrote:
Hi, Folks,
I have a Losmandy GM8G using the Gemini II with the latest firmware update. I am using the polar scope and drift alignment only.
After a 4 star model building, I instructed the Gemini II to point to M42.? However, the pointing was off by about 2 degrees. The only thing I can think of is that all of the stars I used in the model building were in the northern celestial hemisphere and M42 is in the southern celestial hemisphere. Am I correct or am I doing something wrong? Any feedback would be appreciated.
My procedure is to use the polar scope for initial polar alignment, then do a drift alignment. After that I turn off the mount, go back to pointing North/counterweight down position, turn the mount on again and do the model building. I am manually entering in my position and time.?
By the way, does anyone have a good reference for drift alignment technique? Any ideas would be appreciated.
Best Wishes and clear skies,
Russ
Hi Russ,
?
Double check that you centered the correct stars when doing alignment, and that they were really well centered in the FOV (use cross-hair). South/North hemisphere shouldn't matter much to pointing accuracy, unless you have some significant slop in the focuser or mirror of your scope. There are two models for West and East, that's what really matters to building a good pointing model across the whole sky. If you do have some mirror flop or flexure, try adding a few more stars to the model as this can help compensate for these effects.
?
Regards,
?
? -Paul
?
Inaccurate pointing after 4 star model building

 

Hi, Folks,
I have a Losmandy GM8G using the Gemini II with the latest firmware update. I am using the polar scope and drift alignment only.
After a 4 star model building, I instructed the Gemini II to point to M42.? However, the pointing was off by about 2 degrees. The only thing I can think of is that all of the stars I used in the model building were in the northern celestial hemisphere and M42 is in the southern celestial hemisphere. Am I correct or am I doing something wrong? Any feedback would be appreciated.
My procedure is to use the polar scope for initial polar alignment, then do a drift alignment. After that I turn off the mount, go back to pointing North/counterweight down position, turn the mount on again and do the model building. I am manually entering in my position and time.?
By the way, does anyone have a good reference for drift alignment technique? Any ideas would be appreciated.
Best Wishes and clear skies,
Russ
Re: RA and DEC servo motors on Titan mount

 

Thanks Brendan! I¡¯ll check it when I¡¯m back out at the observatory again.?
Re: Meridian Flip

 

On Fri, Jan 31, 2025 at 10:37 AM, Tony wrote:
I changed the Asiair settings to stop tracking 8 minutes before Meridian. And to flip (or GoTo command from Asiair) at 8 minutes past the Meridian.
As for the limits Eastern is at 95.18, Western at 103.40, and Western Goto at 2:30
?
8 minutes past the meridian puts the goto target at 98¡ã. Your safety limit is at 103.40¡ã. A flip will not happen, since the Goto limit is then at 101.10¡ã and the target is 3+¡ã before the Goto limit. The mount will simply try to slew to the target without flipping.
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Try increasing Goto limit to, say, 13¡ã.?
Re: Meridian Flip

 

I changed the Asiair settings to stop tracking 8 minutes before Meridian. And to flip (or GoTo command from Asiair) at 8 minutes past the Meridian.
As for the limits Eastern is at 95.18, Western at 103.40, and Western Goto at 2:30
Re: Meridian Flip

 

On Fri, Jan 31, 2025 at 12:26 AM, Tony wrote:
The flip failed again this evening. However I did notice this clock countdown on the hand controller screen with the word Guide. I did not notice at what value the countdown began (probably at 60 minutes?) but appeared after AsiAir indicated that the first meridian flip failed and was waiting for a second attempt.
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Did you change any of the settings? You said you have a 93¡ã safety limit. This translates to 12 minutes of tracking past the meridian. If ASIAir stops at 1 minute before,? then a total of 13 minutes of tracking to safety limit. Your HC is showing nearly 60 minutes. What's changed?
Re: Meridian Flip

 

The flip failed again this evening. However I did notice this clock countdown on the hand controller screen with the word Guide. I did not notice at what value the countdown began (probably at 60 minutes?) but appeared after AsiAir indicated that the first meridian flip failed and was waiting for a second attempt.

IMG_2853.JPG

Re: RA and DEC servo motors on Titan mount

 

Kurt you can identify your motors by shape see web .?


But in short if the motor has no cooling fins it¡¯s the old std motor. ?But I¡¯m general DEC doesn¡¯t get the workload Ra does so many users keep the old motor on DEC and HT on Ra. ? ?There is no need to change that which is working fine. ? However being a club scope. ? Might be best to have a spare motor for eventualities. ? You¡¯d want to minimise down time.?


You can post images of the motors or whatever. ?It helps identify?
?
cheers
?
?
--
Brendan
RA and DEC servo motors on Titan mount

 

Our club scope is mounted on a Losmandy Titan mount. I noticed that our Dec servo motor has no identifying numbers on it, but our RA servo motor has? Losmandy SVM-HT marked on it. I know that the RA servo motor has been replaced not too long ago, but not sure about the DEC servo motor. The Dec motor MAY be original to the mount when it was purchased in 2012. If I'm reading the RA motor correctly, this is a High Torque motor. Would the Dec motor be the same, or is there no way to tell without any identifying numbers on the Dec motor? Should we change the Dec motor to an SVM-HT so they both are the same? TIA for the guidance.
Re: Meridian Flip

 

On Thu, Jan 30, 2025 at 04:30 PM, Tony wrote:
Thanks everyone for your input. However one question remains open in my mind. Should any of the two boxes on the screen of my pic (attached), showing using eastern or western flip points, be checked?
You don't have to use flip points, these were introduced as an option with Gemini L6. If the two checkboxes are unchecked, your safety limits and the Western Goto limit will be used instead of flip points.
Re: Meridian Flip

 

Thanks everyone for your input. However one question remains open in my mind. Should any of the two boxes on the screen of my pic (attached), showing using eastern or western flip points, be checked?
Re: USB Connection to Gemini 2 Disconnect Issue

 

On Wed, Jan 29, 2025 at 12:07 PM, Bruce Morrell wrote:
Gentlemen,
I am experiencing a similar problem.? My mount computer is a rasperrypi running Stellarmate all up to date using INDI drivers.? Worked fine for two years then got flaky.? Replaced cables, replaced power supply and computer no luck.? Took my laptop running Stellarmate same problem.? Then brought Gemini 2 unit in the house and it works like a charm on ASCOM desktop.? Then took a retired PC running windows to fully upto date with all brand new software and it would not work.? So, I have tried this on Stellarmate using Indi driver, on three different computers no joy, tried it on two different windows computers, one new high-end desktop, the other a retired desktop and only one worked.? Network connection using Indi worked well so it is not the Indi driver.? Any thoughts??? Bruce
Hi Bruce, can you describe in more detail what didn't work with the three computers and what does "flaky" mean? Are you able to connect to Gemini but then it randomly disconnects? Or are you unable to connect at all? Are you using an ethernet connection in all four cases? Anything different in how you hook things up between these four (any additional switches, routers, adapters?)
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Regards,
?
? ?-Paul
?
Re: Hand Control switched RA and DEC

 

On Wed, Jan 29, 2025 at 03:32 PM, TimS wrote:
Hi, group, I'm hoping this has been solved before. I was trying to track on the sun. During the process I realized that to correct for the sun's drift in time I had to use the dec button on the hand control. I assume I'm not the first to experience this. I'm hoping this is a battery problem. Any suggestions?
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Thanks, Tim.
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I checked the basics, I was using the AC power supply.
?1. Time in the Hand Control was wrong on startup and was corrected.
?2. The UTC time zone was wrong on start up and was corrected.
?3. the site's Longitude and Latitude was correct on start up.
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How good is your polar alignment? If it's very approximate, you may have to keep adjusting DEC to track the sun.
?
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Re: Hand Control switched RA and DEC

 

Sounds like battery was low and system clock stopped. ?Other data was held in eeprom. Replace battery but probably do a factory default reset as you don¡¯t know what else is corrupted.?

cheers
--
Brendan
Hand Control switched RA and DEC

 

Hi, group, I'm hoping this has been solved before. I was trying to track on the sun. During the process I realized that to correct for the sun's drift in time I had to use the dec button on the hand control. I assume I'm not the first to experience this. I'm hoping this is a battery problem. Any suggestions?
?
Thanks, Tim.
?
I checked the basics, I was using the AC power supply.
?1. Time in the Hand Control was wrong on startup and was corrected.
?2. The UTC time zone was wrong on start up and was corrected.
?3. the site's Longitude and Latitude was correct on start up.
Re: Meridian Flip

 

Hi Tony,
Both your Eastern and Western Safety Limits are set to 93 degrees... or 3 degrees past the meridian.?
The point of Meridian Flip = Western Safety Limit - Western GoTo Limit.
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Your Western GoTo limit is 5 degrees. You are telling the mount you want to flip 1 degree before the meridian and yet you are telling the ASIAIR to stop tracking one degree before the meridian. That may be your problem.

Recommend a Western GoTo Limit of 2 degrees and 30 seconds (default) to start and definitely follow Sonny's recommendations.
Re: Meridian Flip

 

NOTE: By "Manual Swing" I mean running the mount with the Gemini II Hand Controller.
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Not physically moving the mount.
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--
Sonny Edmonds
GM811G HD
Re: Meridian Flip

 
Edited

Hi Tony,
Doing a meridian flip was my Bain to getting NINA to flip. Here is a part of my journey. [email protected] | OK, so close but yet, so far. NINA and Automated Meridian Flips... still.
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I do not own an ASIAir. So can't say if my settings for my mount's limits would work for you.
If you try them, you MUST make sure your mount and telescope will not crash before the limits stop the movement.
Finally, someone named David published his settings and I tried them, and they worked for me.
I've since gotten my GM811G HD to reliably flip for me.
Just yesterday I rechecked my settings and last night proved them out in automatically running in NINA.
These are set in your Gemini controller. Under: Mount>Limits and I have NINA use my Gemini II's settings.
How an ASIAir does this is beyond me because I don't have one. My entire operation has always been run through a powered USB hub on my telescope and a single cable to my laptop.
I've never needed an ASIAir, so your image is a bit foreign to me, though I did look it over.
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Limits are a primary function of your Losmandy Mount and the Gemini Controller. Because your computer has no clue where your mount is Physically.
>Eastern Limit: 95.18
>Western Limit: 103:40
>Western Go To: 2:30 (This I think is automatically set by the Gemini)
?
I use a stylist with my Gemini touch screen. No touch screen likes my fingers, and Scott and Tanya both use stylists in their demo video's. Works for them, works for me.
What I do is to run the mount to where the camera is close to, but well safe, from crashing into my mount anywhere. Then tap the Set Limit Here icon on screen. Don't be confused when the screen gets a bunch of X's on it, just proceed.
Do the same manual swing to the other side of your mount and again tap the Set Limit Here icon again. Again, don't be confused by the X's on the screen.
Save the new settings and then test them manually. The mount should beep and shut down as it comes to the limits set. If you let go of the button you are swinging with, then reinitiate it the mount will continue swinging and you will crash your telescope into the mount.
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When doing these Limit Settings don't forget to swing your DEC to make sure everything is clearing your mounts hardware.? Because you want to avoid any possibility of breaking or damaging your telescopes focuser or camera.
My mount has a 12" extension to make it a "Portable Pier". So, I have substantial clearance from my HD tripods legs. But others (you) may have interference that you must deal with if your load (Telescope and Camera) can be impacting anything when running unattended.
The mounts limits are to protect it, and the load it is carrying. And only your mount and Gemini II controller can do that. Not the ASIAir, and not your computer.
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OK, try my settings for yourself.
I made several actual test runs with mine in the daytime by picking a star near the Meridian as a target, then sitting there and watching as the star crossed the meridian and the mount did a meridian flip.
I was pleased as punch when it did! And I wasn't sitting out in my insulated Carhart's in the dark waiting with my red LED headlight to make sure things didn't crash.
Once you find your limits "sweet spot", write it down so you don't lose it if you have to do a factory reset on your Gemini II. How do I know this?
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Good luck! I do hope this can help you. Paul is good as Gold with his advice as well. He's given me, and many others the key to happiness with our mounts.
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--
Sonny Edmonds
GM811G HD
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