Naive star filter visible at night in certain country I have a HYG catalogue and I'd like to filter out stars visible at night and in Europe. 

Doesn't have to be exact. I was assuming that it'll be all stars with positive declination, but I wasn't sure about RA values.

Thanks, Michal
In the answer https://physics.stackexchange.com/a/26787 you can find an example how to convert celestial coordinates to horizon coordinates an than check, if the altitude is above the horizon