Mag in Stars window?

Image processing, astrometry, photometry, etc.
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Posts: 2
Joined: 20 Feb 2023, 19:34

Mag in Stars window?

Post by ahae » 02 Jul 2024, 12:47


perhaps a too simple question, but I couldn't find the answer in the Help files, the manual or the forum:

I'm trying to calibrate DSLR images of the different colors (RGB) photometrically (the ADU <-> Mag correlation).
As for photometry the UCAC4 catalogue with the APASS magnitudes is remommanded, I installed it.
Using the G picture, I select ApassV in the Star atlas setup ("Band"), and I suppose these V magnitudes are given in the Mag column.
Using the B picture, I select ApassB, and would suppose to see the B magnitudes in the Mag column, but these are the same numbers as before, though I deleted the calibration.
I then compared the Mag in the Stars window with the UCAC4 V magnitudes from VizieR (identifying the stars manually..), and they were also different....

What am I doing wrong?
How can I get the V and B magnitudes to calibrate the G and B images?

Thanks for help!

Posts: 477
Joined: 03 Dec 2018, 21:43

Re: Mag in Stars window?

Post by fabdev » 05 Jul 2024, 21:39

Hello, after switching the magnitudes in the Star Atlas, it's required to repeat the link from the Star Atlas to the Image (from the Star Atlas, button: "Reference stars - automatic" or "Reference stars - manual").
If some stars with magnitude are already in the list, it's required to reset their "P Ref" flag (pressing P), or just to delete them all, before the link.

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