Stellarium issues with Meade LX200GPS

[Gadgetman Bowen]

I have been trying to use Stellarium partly with my Meade LX200GPS telescope for many years now.  I can never get it to coordinate slew  SYNCs with various ASCOM Drivers I have tried or just using my hand controller alone.  It always misses the object when I use Stellarium to slew.  When I use my hand controller or other software such as NINA to slew to the target, I am dead on or very close.  When I center on the target and command Stellarium to SYNC, the bullseye icon is always off on the star map.  I have even set it up to let Stellarium control, which really does not work for me and again had SYNC issues.  I need to use my hand controller at times and do not like for complete telescope slewing control to be just with the computer.  ASCOM drivers tried are Meade Generic, Device Hub (which replaced POTH per the ASOCM web site) and the Meade LX200GPS/R.  Basically, now I just use Stellarium as a map to see what is up that I might want to see or photograph.  With NINA I do connect to Stellarium so I can use the coordinates feature to import into NINA when I set up a sequence.  Odd that Stellarium and my Sky-Watcher EQ6-R Pro work very well with Stellarium and NINA.  So, what is the issue with the Meade.  Oh, I have made sure the AutoStar II hand controller is up to date on firmware; version 4.2l.  Any suggestions from Stellarium users?    

[Georg Zotti]

My only idea is coordinate reference: J2000 vs. equinox of date.

[Gadgetman Bowen]

I am not familiar with the reference settings you mentioned.  What should the setting be and where do I change it.  I know I have seen the references somewhere in Steallarium.

[Georg Zotti]

Please search for J2000 inside chapter 15 of the User Guide. I don't know more.

[Gadgetman Bowen]

Thank you and will do.

[Wolfgang Laun]

Off-list.

If the difference between the expected and the displayed location should not be regular across all of the sky. It's not too complicated to compute the movement since J2000. Jean Meeus' "Astronomical Algorithms", Chapter 21, Precession, contains the formulas. - You might even find an online implementation.

Cheers

Wolfgang

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Wolfgang Laun

[Hans]

Some questions that may help investigate :

- How far off is Stellarium ? And is it always the exact same amount and in the same direction over various sessions ?

- If you connect with two planetarium programs (I assume ascom can do that, idk as i'm not on windows) what are the coordinates in one and in the other ?

[Gadgetman Bowen]

Last night I worked on settings suggested from you all.  I tried changing to several ASCOM drives I had mentioned and the settings in Chapter 15.  I double checked Com Port numbers.  Nothing worked to make the Stellarium’s scope target icon (bullseye), which was way off from the actual telescope’s location, to SNYC.  I still was able to use the Stellarium’s coordinates with NINA when I wanted to setup a sequence using the SHIFT Left Click method on an object or even just click on the sky object like M42 in the attached JPG.  The telescope did not slew to any target selected on the Stellarium’s sky map when I clicked the Slew to Target button using Stellarium.  Slew to target does work in NINA.  I will say that sometime in the past the bullseye was a little closer than the attached picture, but last night it was pretty much this distance on the various settings I tried.  As for trying to slew with Stellarium, the bullseye did move back and forth some but never to the actual target, always going back to where it was originally.  I do not know what the problem is, but it has been this way for years even before I started using NINA.  Thus, that is why I use Stellarium as a map to find what I may want to photograph.  I guess I will just live with this issue and forget a resolution.  Thank you all for your advice.

[Georg Zotti]

OK, that's not equinox J2000 vs. equinox of date. It looks like a grave alignment error. Stellarium sends commands like "GOTO RA=2h34m34s, DE=43°17'23''". It is assumed that the instrument has been carefully polar aligned first. I cannot say what "sync" really does.

[Gadgetman Bowen]

The command to move the bullseye in Stellarium to the actual object that is in the telescope’s eyepeice is Control C on the keyboard, which is the SYNC command.  My newer version of Stellarium has a window where that can be done now.  That command should move the bullseye to the box around the object.  In the JPEG, the object’s box is around M42.  I did do a star alignment with the telescope prior to connecting to Stellarium.  My LX200GPS is on an equatorial wedge.  I always polar align and star align prior to turning on any other programs.  After the hand controller gets the GPS information and I polar align, I do a one star alignment using the EASY alignment option selection from the hand controller.  I could do a two star alignment but most times the one star and my polar alignment is good.

This YouTube video shows the SYNC issue and how to SYNC.  However, my LX200GPS and the ZWO for some reason will not plate solve.  That is another issue.

https://www.youtube.com/watch?v=dtbe4z0MQ9I&ab_channel=Martin%E2%80%99sAstrophotography

After watching this video I will recheck the EQMOD settings rgearding the J2000 setting.  I do not use Sequence Generator Pro.  Some clear skies for a little while tonight.

[Hans]

This differs for me :

On Thursday, December 2, 2021 at 1:07:19 AM UTC+1 gadget...@ wrote:

The command to move the bullseye in Stellarium to the actual object that is in the telescope’s eyepeice is Control C on the keyboard, which is the SYNC command.

 If I press F1 in Stellarium for help and scroll down to 'Telescope Control' I find ao. these :
Move telescope #1 to selected object: Ctrl+1
Sync telescope #1 position to selected object: Ctrl+Shift+1

What does it list for you there ?

[Gadgetman Bowen]

I thought I had added to this post about the status of success with Stellarium and my LX200GPS connection.  I do not remember what I did but I did get the two to interface.  Now some clear nights and try and remember what I did.