Some guide issues

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gundamrx91
Posts: 41
Joined: Fri Nov 08, 2019 10:54 am

Some guide issues

Post by gundamrx91 » Mon Jan 27, 2020 3:01 pm

During the last night photographic session I've taken a lot of frames with my setup: iOptron GEM45, ASI Air, ASI294MC as main camera and ASI290MC as guide camera.
Sometimes I got some shifted frames then the previous, and having the guide it's quite strange. Sometimes the stars were elongated, and it's strange too, but I don't know why.
Could you advise something, please?

Giuseppe

W7AY
Posts: 223
Joined: Fri Jan 25, 2019 3:38 am
Location: Portland, Oregon, USA

Re: Some guide issues

Post by W7AY » Mon Jan 27, 2020 3:58 pm

Hi Giuseppe,

I am assuming that your glide graphs look OK?

If so, your guide scope could be shifting relatively to the main OTA during the exposures. Check to make sure that the guide scope is mounted securely and solidly to the OTA. If you are using an OAG, make sure the guide camera is secure to the OAG.

Just a few arc seconds of wobble will cause the elongation that you observed.

A loose optical train can also cause the problem. Make sure both the guide scope and the main OTA don't have loose spacers or loose camera attachments. If you are using filters, make sure that they are no loose.

Good luck,
Chen

gundamrx91
Posts: 41
Joined: Fri Nov 08, 2019 10:54 am

Re: Some guide issues

Post by gundamrx91 » Mon Jan 27, 2020 4:22 pm

Thanks Chen for your fast response :D
Yes the guide-graph is pretty good with some bigger elongation in AR and Dec, due to the wind, but generally is good.
I haven't thought of the guide scope shifting, and yes next time I'll check everything, guide scope, guide camera, main camera (with the focuser).
I'll let you know ;)

Giuseppe

gundamrx91
Posts: 41
Joined: Fri Nov 08, 2019 10:54 am

Re: Some guide issues

Post by gundamrx91 » Thu Jan 30, 2020 7:53 am

Yesterday I tried again, but without success. Stars were always elongated. I've noticed that in telescope action there were two parameters not set: the guide rate and the tracking. Could it be' due to the firmware update? In case Have I to set the same valute of the software mount, I suppose?
Please give me some advise because I don't know what to think.
Thanks

Giuseppe

gundamrx91
Posts: 41
Joined: Fri Nov 08, 2019 10:54 am

Re: Some guide issues

Post by gundamrx91 » Thu Jan 30, 2020 3:00 pm

I was forgetting to write that the guide-graph is often specular, so the AR graph is pretty equal to the Dec graph, but specular. Can be useful for analyzing the problem?
In general wich are the best general guide-parameters? I mean of calibration, max ar/dec duration.

Giuseppe

gundamrx91
Posts: 41
Joined: Fri Nov 08, 2019 10:54 am

Re: Some guide issues

Post by gundamrx91 » Mon Feb 17, 2020 5:30 am

The issue was related of a firmware update, that has changed the guide settings. Basically there weren't set the tracking and velocity guide settings.
Two days ago I try a photographic session and everything is gone well, but yesterday night after 30 minutes the guide stopped to work, loosing the AR. I don't know why but it didn't guide the AR axis, but only the Dec. I had some issues setting the guide parameters as well, as the focusing. It was like the guide scope was dumped, but it hasn't, so the stars had always a glow.
Any advice?

Giuseppe

gundamrx91
Posts: 41
Joined: Fri Nov 08, 2019 10:54 am

Re: Some guide issues

Post by gundamrx91 » Tue Feb 18, 2020 10:37 am

Any suggestion?

Giuseppe

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Sam
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Re: Some guide issues

Post by Sam » Wed Feb 19, 2020 8:03 am

you'd better take some screen shot and upload for us to analysis
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gundamrx91
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Joined: Fri Nov 08, 2019 10:54 am

Re: Some guide issues

Post by gundamrx91 » Wed Feb 19, 2020 10:18 am

Thanks Sam, I'll do it as soon as possible.

Giuseppe

gundamrx91
Posts: 41
Joined: Fri Nov 08, 2019 10:54 am

Re: Some guide issues

Post by gundamrx91 » Sun Feb 23, 2020 6:59 am

I think the problem was about the guide settings, because in the last session everything has gone well, even though I had some strange behaviour. At the beginning the app didn't recognise the GPS coordinates, so I had to set them manually. I tried to switch off the ASI Air and close the app, but without success, the app every time asked me to set the coordinates.

Thanks for your support.

Giuseppe

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