distant stars seem to be light sources and have lense/flare effects,

are you making a flight simulator or a movie?

there won't be any lens effects in a flight simulator. in a movie there will be.

unless the view out the window is a virtual window displaying what a camera sees - then there would be lens flare.

while lens flare looks cool, especially in space scenes, It does not occur in real life when the "camera" is a human eye, only when its an actual camera, like a movie camera.

another realism issue like the twinkling stars.

the way i handled solar systems etc was to... (thinking back, this was about 15 years ago...)

there was a map that said where stars were, and what planets and moons were in the system. A 3D map.

when you flew close to a system, you draw the star, planets, and moons. a skybox was used to provide a distant star field background. galaxy billboards were drawn just inside the skybox in the four cardinal directions, and up and down to provide visual orientation cues. and then there was the streaming stars particle system. this was a cloud of stars around the ship that moved as you moved, giving the streaming stars effect (complete with Doppler tails) seen in Star Trek when they're flying through space. the location of planets and moons was based on a global turn counter (# of game turns or frames since game start). so they orbited around, and all that cool stuff.