- Celestia Motherlode
The Celestia Motherlode is the central repository for Celestia add-ons. Hundreds of add-ons are available on the Motherlode with thumbnail screen shots for easy browsing.
- Add-on releases on Celestia Forums
In this forum, you will find many add-ons created by the Celestia community.
- Selden's Catalogs of Objects for Celestia
- Introduction to Creating Celestia Add-Ons
Selden Ball has created a very helpful introduction to creating add-ons for Celestia. If some of your favorite astronomical objects are missing from Celestia, or if you want to create an entirely ficitious planetary system, then you'll be interested in reading this add-on introduction.