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

Bi-monthly release with minor bug fixes and improvements

Guiding/Dithering in KStars 3.5.5 stable

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I’ve just upgraded my Astroberry installation and am impressed with the hard work that has clearly gone into the latest adjustments and improvements.
Running the system tonight for the first time, I have had a successful test run of most functions. However I’ve now had to revert to KStars 3.5.4 due to concerns about the new implementation of the internal guider. Dithering seems to throw the Dec axis guiding off kilter. I have twenty four minute exposures to examine. It’s possible that the images will be OK even though the guiding error graphs and figures look awful. I’ll add more information when I’ve downloaded it from the RPi SSD.
2 years 5 months ago #76515

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So I've gathered some more information about last nights issue. Firstly here is the Analysis plot from last night's session.
 
As you can see the Dec guiding 'error' appears to form a modulated rectangular wave with a certain amount of noise but otherwise staying at a constant level during most of the image capture. It seems the plot is tracking the absolute positional error plus the dither amount, rather than the error from the dithered position. I also highlight the tooltip showing that I had requested the Dec axis correction pulses to be displayed. There are none shown although they were certainly active.
I started the session without changing any guiding parameters away from the default values. I was somewhat surprised that the aggressiveness on both axes is default 0.75 rather than the more typical 0.5 (133.33/266.66....).
In spite of the graph plot issues, the results are not bad (there was some wind around).
Last edit: 2 years 5 months ago by Avocette.
2 years 5 months ago #76524
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Thanks for the report. I'm happy to look into it.

Am I correct: I understand your report as saying it's a graphics error--that is, the guiding is decent, but the graphs report offsets in DEC corresponding to dithering (but it doesn't do this for RA).
Are you using SEP MultiStar? Is the same thing reflected in the guiding page's graph?

Just in case it's some kind of temporary axis issue, can you reload the graph? That is, you could read-from-file from a different session, then go back to this one.

In general for guiding issues:
Please point to a full log uploaded somewhere (e.g. google drive) with verbose, File logging enabled for at least Indi, Guide, Mount and Drivers/Mount. 
Also, though I may be able to find it in the log, not sure, please let me know all relevant parameters--e.g. screen shots of your guiding options pages
(Calibration, Guide, Dither & GPG) and the guide page itself.

Thanks,
Hy

FYI, this isn't an "affects everyone" bug--e.g. I dither too but don't see that in my imaging. Here's part of my graph from last night using the latest software. For no real scientific reason I tend to dither 2 pixels every 4th image.
 
 
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2 years 5 months ago #76535
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One more thing for you to check.
Can you look at two of your images (just before and just after a dither with this display issue) and see if in fact it did dither by the amount graphed/expected?
2 years 5 months ago #76536

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I’ve opened the data several times after looking at files from other sessions with no changes. Of course the others were recorded under KStars 3.5.4 since I only used 3.5.5 once.

I did notice that the guiding error plot during the live session showed the step quantisation in the Dec axis matching the Analysis graph.

To follow through I’ll have to learn techniques of logging etc. but I’ll do my best in the next imaging session.
2 years 5 months ago #76540

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SOLVED - Tonight was predicted to be a second opportunity to test KStars 3.5.5. In between the first test and today, Radek has posted a new Astroberry image 2.0.4 after almost a year in which I have been regularly updating/upgrading v2.0.3 from the repositories.  A couple of other strange glitches had appeared in the user interface and controls (the Ekos tabs mysteriously switched back to the top of the window etc.) so I decided to download a fresh image of 2.0.4 rather than try to repair my present installation. The clean new image is working fine tonight, and if this carries on I will not go back to the other version.
Thanks Hy for your help…..when you pointed out that my problem might be unique to me, I felt it would be better to take this approach.
2 years 5 months ago #76588

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