Photometric distant stars and improved labeling

Displaying distant stars is a difficult task because their luminance is really high, however,  their apparent size is much lesser than a pixel. Some solid angle calculation can give a solution for this.

Displaying  deep space objects is not as exact as the distant stars in Demeter, it needs approximation for the magnitude to luminance conversion and for the surface area calculation as well.

The advantage of this solution that they can be filtered by an illuminance threshold expressed in nanolux and then can be labeled (in the right image these are labeled: all celestial bodies (green) and the filtered DSOs (purple))