Hello,

I want to get all the stars in a certain area: how am I supposed to use the star index? 1 is star, but I don't get that many stars so I wonder from  which 0.X value I can consider it star enough. Any help?

Dear Chiara,

the CLASS_STAR we include in the master table is the maximum value reported by Source Extractor from any image of that object. It's well documented that CLASS_STAR trends towards 0.5 as the signal-to-noise gets low, so the answer will depend on the magnitude range you're interested in.

But from the nearly 600,000 stars in GALAH DR3 (magnitudes 9-16), more than 95% have CLASS_STAR > 0.9.

Regards,

Christopher Onken

SkyMapper Team