I'm playing with an idea of making a little program to draw the sky. Nothing fancy, just for fun. And I'm reading about projections.
Now I know that I must use different projections depending on my field of view. My idea is to start with fairly large field of view (FOV), say 45 deg (and therefore with a large distortion) and be able to reduce the FOV ("zoom in").
What should I use?
Another thing is with transitions between two projections. They should look almost the same for at least one FOV, to make it smooth.