For anyone who likes to fly at twilight or in the night, the following two enhancement tools shouldn’t be missed.
The HD Moon Texture by Marco Fischbach can replace the default FSX moon texture (64×64) with one of its higher resolution moon texture sets — 2048×2048, 1024×1024 and 512×512.
My recommended choice is the 1024×1024 set, which is good enough to render a pretty and realistic lunar terrain effect, without sacrificing FSX performance.
The latest version 3 can be downloaded from FlightSim.com here.
The AutoStar by Chris Wright is a utility that can generate real and accurate star positions according to a celestial database developed by the Smithsonian Astrophysical Observatory for the years from 1950 to 2050 up to a small fraction of a degree.
By default, FSX produces about 9,000 stars. AutoStar, out of the box, increases the number to about 16,000. Actually, the database contains up to a quarter of a million stars down to magnitude 9 — a level at which stars are far too faint to be seen by the naked eyes.
Furthermore, AutoStar offers a number of enhanced controls over the brightness, color and dynamic range of stars, as well as comets and celestial circles.
Version 1.01 of the file can be downloaded from FlightSim.com here.