No automatically detected stars

[LeoBosse]

Hello, I just installed skyfit2 on my ubuntu 22.04 laptop following the wiki, and started following this youtube tutorial. Once opened, I can play with the astrometry parameters to align approximately the catalog stars to my image. But there are no green circles appearing automatically, and pressing C does nothing. The "fit" button is greyed out and cannot be clicked. I tried to play a little with the config file parameters under [StarExtraction] without success. I have 9 .fits images with background around 500 counts, while the stars have a few 1000 counts. The limiting mag is a least 7, and image dim are ~30x40degrees for 4144x2800 pixels. The FPS is 0.2 (5 sec exposures).

Why is that? Did I miss something during install? Is it because of a low SNR? Is there a way to force the detection?

Thanks a lot in advance for your help!

[dvida]

The star detector requires fine-tuning and it only works on RMS-type FF files. But you don't need any detected stars to make a good plate. Just centroid the stars yourself and you'll be good to go. Also, because the exposure is so long, I recommend you analyze images individually (one per folder), otherwise you might get long star trails in the combined image.

[LeoBosse]

Wow, thank you so much for such a quick answer! Ok, I'll see how to do by hand. Do you know if there is a way to convert fits to RMS-type FF files?

[dvida]

It might be possible, I haven't looked into whether FF files can support more than 8 bits. It should be feasible in theory, but we might have to modify the code in a few places. You should be able to make a fake FF file by manually setting some parameters. E.g. see this function how FF files are structured: https://github.com/CroatianMeteorNetwork/RMS/blob/master/RMS/Formats/FFfits.py#L37 The data should be written into ff.maxpixel and ff.avepixel, while you can leave maxframe and stdpixel black (all pixels set to 0).

[LeoBosse]

Thanks for your help, I managed to load our fits images with detected stars! Playing with the FFfits.py read function, I had to adapt the header parameters to ours as well as the HDUList, set full_filename=True by default. Also changed the FFfile.validFFName function to accept fits files not starting with FF and the FFfile.filenameToDatetime to properly read our file names. It works like a charm!