Plate solving using the 585MC pro w/ LX200 12"

[Jean-Francois]

Hello,

Yes ... Robin is sometimes very productive with at least one update per week.
So ... for some people a "new" version is already an "old" version for other people.

Regards,
Jean-Francois

[geoscoping]

well,

Not the night I wanted to have in the field. I feel like this is due to my limited experience and understanding of how plate solving works.

I set my scope up and started up sharpcap. It plate solved the first time just fine and then again when I asked it to solve and move to a target. Once again, it solved perfectly, moved to towards the target (or so I thought) and then failed to solve the second time. What I realized however, is that its not moving towards the target, its moving about 45 degrees off from it and trying to solve again and failing, of course. Let me explain, I found a target galaxy and pointed it in the area, seemed like it would only need to move a small amount downwards to bring the target into view. It skewed about 45 degrees from where the target was.

I am in alt-z currently if that's a question that comes up.

I have very limited experience with plate solving in general so I am not sure what is happening. I did think about it on the way home and thought about the fact that I didn't start the mount out pointing the tube north and the control panel south, but I don't think that matters but again I may be completely incorrect on this and that may very well be the issue.

Any advice would be greatly appreciated.
-George

[admin]

Hi,

probably the best bet would be to check the SharpCap log (feel free to post the log here). That should record the initial position, plate solve results, GOTO movements requested after the plate solving, etc. Please also try to note the time at which you made the attempt, so that I can focus on the right part of the log. You can find details of how to locate SharpCap log files from previous sessions here : https://docs.sharpcap.co.uk/4.1/#The%20SharpCap%20Log

Normally, SharpCap only checks within 15 degrees for plate solving results when you do a plate solve and sync, so moving 45 degrees would be unexpected.

cheers,

Robin

[geoscoping]

I have advance logging on and its over an MB and its also way to big to put in the text box. How could I send the log to you?

[geoscoping]

I found where I started to plate solve and made an edited log file. hope it has everything you need

[admin]

Hi,

thanks for sharing the log - the one plate solve attempt in the log that succeeded found a result at co-ordinates RA=23:49:58.0,Dec=+18:53:38 - however, the reported mount position when that attempt was tried was RA=12:26:18.0,Dec=+52:46:02, so the position came out a long way from where the mount was supposedly pointing.

On that attempt, you had just requested a plate solve (no action to recenter afterwards), but if a similar thing happened using the plate solve and sync function then a large GOTO movement could happen afterwards to try to correct the large pointing error.

The other two attempts in that log file failed to solve - the first was a simple 'solve with no sync' that found no solution after searching the whole sky. The final attempt was a 'solve+sync' as part of a GOTO to the Triangulum galaxy. That searched out to 30 degrees and found no match.

The one attempt that worked reported a calculated focal length of 120mm with the ASI120MM - that would be about right for a small guide scope.

I would have thought that plate solving would be pretty reliable with a 120mm focal length ans ASI120MM, so this is odd. It's possible that the initial GOTO movements of the telescope are significantly off for some reason (time zone issues, or incorrect time?). It would be worth checking with some separate source that that the telescope is going to the right part of the sky - perhaps some phone app that shows the current sky (there is a mobile version of Stellarium). If that all checks out, try increasing exposure/gain (to ~4s and mid to high gain) to see if that helps. Finally, if still now joy, grab some images using the 'Snapshot' button when plate solving fails and share them here (along with the log) and I can check if the image matches up with the expected part of the sky.

cheers,

Robin

[geoscoping]

Thank you so much!

So I do see that anytime I connect the mount to sharpcap it says that the mount is reporting the incorrect time, then I select the option to have sharpcap change the time to the correct time. Would it be possible that its not actually able to do this and that's why I am having the issue? I believe I corrected the time issue on the mount side of things now so that it will show the correct time for now on.

So I switched to using the ASI120mm guide scope for plate solving as I was having no luck with the 585MC pro. I think I just need more practice with it

[admin]

Hi,

yes, it's entirely possible that the mount could ignore SharpCap's attempt to set the time correctly - the ASCOM specification says it *should* take notice of it, but plenty of ASCOM drivers don't do exactly what they are supposed to in response to certain requests, so who knows ..

Hopefully with the mount time sorted, the initial GOTO movements will be the right part of the sky and then everything should go to plan.

cheers,

Robin

[geoscoping]

Thank you

Fingers crossed