Color Calibration version 9/29/2025

[DrBobAZ]

Hi Robin

Just installed SC 9/29/25. Seems when I try to use color calibration, it returns an error something to the effect that the calibration failed because there was no data for B-V star.

I did not do anything with databases etc (can I even do anything?)


any ideas?

Thanks

Bob

[admin]

Hi Bob,

I bumped into your post on CN before I found this one, but I will repeat the same info here, just in case of others finding the problem and ending up on this thread...

the message about 'No data for BG' (or, equivalently no data for GR) means that the B-G graph at the right doesn't have a good correlation between the expected star colours from the catalog data and the measured star colours. This can be due to a few different reasons, including

* The stack is relatively short so far, so there is a lot of noise which makes the star colour data more scattered

* A low number of detected stars in the image, meaning there isn't much data to work on

* Not many matches between detected stars and catalog stars, again giving not much data to work on

You will likely see this message along with the relevant graph (either the GR or BG one) being a scattered mess rather than showing a good pattern (line or curve).

Nothing has changed in this part of the code for several versions (the last change here was late August, fixing a problem where the tolerance distance for matching stars in the image to stars in the catalog was calculated wrongly). I would suspect that this failure is related to the image being stacked giving poor data and the same would have happened for that image in previous versions.

cheers,

Robin