Here, I will be posting any addons that I have made. Stay tuned for some addons that I worked really hard on!
Added after 9 minutes 52 seconds: My version of the Kepler-90 system. Textures were taken from fungun and Fugazi's Star Trek addons from the Celestia Motherlode, and the star data was from Wikipedia and the exoplanet orbits were from exoplanet.eu.
SpaceFanatic64, your coordinates are a bit off. To calculate the RA and Dec, you can use a converter (I recommend http://www.astrouw.edu.pl/~jskowron/ra-dec/, since it's very flexible).
For example, for Kepler-90 just enter "18 57 44.0384 +49 18 18.4958" and pick the eleventh option, so that's "284.4334933" and "49.3051377".
gironde, Good catch. It seems that the site has a problem when it only converts the right ascension. However, if you enter in both the right ascension and the declination, the problem disappears.