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INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

Internal Guider Issues

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Hi everyone,

I have been having an issue lately with the internal guider. I believe there is something I am doing that is wrong, but I am not sure where to start.

First of all, my issue is that I am getting star trails when guiding. For instance, I took a 120 second guided and unguided image...and to my surprise the unguided image had round starts but my guided started to get elongation(RA Axis).

I was shocked when I saw that because it really doesn't make any sense. It has to be a setting that I had input correctly for the internal guider. The only thing is that I have been using auto star, so the calibration should have taken care of everything.

Another issue I am thinking of is differential flexure between my guide scope and main imaging scope.

Not sure where to start with this, if anyone has any ideas I am all ears
3 years 6 months ago #59137

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Replied by Hy Murveit on topic Internal Guider Issues

If you can easily reproduce, can you attach a log? Please turn on debug logging for the guider.
The below may be overkill, but what the heck.

On linux the log is found on ~/.local/share/kstars/logs/$DATA/*.txt
On other OSs, click the "Open Logs Directory" in the logs menu to find it.
A couple of images where you have bad guiding, (and please verify that you have much better stars without guiding right after).
-







When you guide, can you please use the SEP MultiStar detection algorithm



Also, importantly, when you start guiding, made sure the system calibrates well, and look at the resulting calibration and see that the two line in the calibration plot are at near right angles.
The calibration plot is one of the tabs in the lower-right plot on the guider page. Select 'Calibration Plot' to see it.

In fact, please also include the guide log (on linux that's at ~/.local/share/kstars/guidelogs/*) and the analyze log if you're running from the latest code (that's at ~/.local/share/kstars/analyze/*).

Sorry for all the work/logs,
Hy
3 years 6 months ago #59154
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Replied by Jose Corazon on topic Internal Guider Issues



Definitely provide the logs, INCLUDING the guidelog. The latter is very important to determine how the deviations are happening.

Also, we need to know your equipment. What mount are you using?

I can relate to your problem. It is most likely not caused by the internal guider, but may be resulting from friction or insufficient power of the stepper motors or from excessive backlash.

I am trouble-shooting a similar problem right now and I can tell you that the problem is not in the guide module, but in my mount. In my case the problem manifests in DEC and the problem more than likely is a current limit that is too low for the stepper used.

Finally, is the guiding rate set correctly in Kstars? Sidereal, not solar or lunar?

Jo
3 years 6 months ago #59157

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Replied by Paul on topic Internal Guider Issues


Deesk06,

This is possibly due to guiding on a hot pixel.

Set the guider to take a dark and see if the issue continues.

Paul
3 years 6 months ago #59161

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Thaks Hy,

I will test that out. Was not using SEP Multi star. I will also get logs next time I am out. I don't expect to be imaging for a few days again after tonight (just picked up now).

I do however have a feeling it is differential flexure. I am taking subs and some are coming in okay and some have star trails, some in DEC and some in RA. Really weird. My total RMS was the best it has ever been as well at about .30 to .45 I ordered an OAG, however, in the mean time I am going to still take in all of your tips. Seems like I should be using those settings permanently. Will be nice to see what it can do!
Last edit: 3 years 6 months ago by Daniel DeSclafani.
3 years 6 months ago #59166

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Replied by alacant on topic Internal Guider Issues


Hi

Of course, send the logs but...
Just one thing I did which produced the same result: on the guide tab, I had specified the primary telescope, rather than the guide telescope. Yeah, I know. DUH...

Maybe worth checking?
Cheers,
Steve
3 years 6 months ago #59175

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Replied by Jose Corazon on topic Internal Guider Issues

It would still be good to see your logs and know what equipment you are using. RMS 0.3 is indeed extremely low. That support's Steve's hot pixel hypothesis.
I would be surprised if flexure were the problem, unless you are using a superlong focal length telescope. For instance, I see no flexure with an RC8 at 1600 mm and a 280 mm guide scope.
3 years 6 months ago #59180

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I'll get logs as soon as I am out again and post here. Im not sure how to tell if I was guiding on a hot pixel. I'll have to give it a shot again. Seems plausible. I was sitting at .3 from time to time then going to about .5 RMS". I am usually around .5 - .7 though.


I have a HEQ5 w/ Rowan belt mod. Meade 6000 80mm Apo, 60/280mm guide scope. ASI 120MM Mini,

Main imaging camera is ASI 183mm pro.
Last edit: 3 years 6 months ago by Daniel DeSclafani.
3 years 6 months ago #59181

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Hi everyone, it looks like I had gotten the issue sorted out. It seems like it did end up being a flexure issue. I replaced my guide scope with an OAG and it solved my issue. Every single exposure had no sign of the previous issues I was having. Ill be able to confirm that again tonight.

Anyway, I tried SEP multistar and it seems like it worked well..I am going to get the guide logs(not home right now) however, my DEC had this issue where it would start to drift off..It would happen when auto guiding first started, and after every time I was dithering. I didnt watch it the whole night, but that seemed to be the pattern it was following. Once I get the logs then hopefully someone can confirm that(I have no idea how to read logs).

Edit: My RMS" was .7 - .9 which is acceptable for my mount
Last edit: 3 years 6 months ago by Daniel DeSclafani.
3 years 6 months ago #59531

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