FlightGear Flight Simulator: free open-source multiplatform flight sim
Java3d scenegraph editor
Cross-platform open source software for astrophotography
Highly accurate ray-tracing software system for UNIX computers
HSPI does parallel capture and sky surveys.
Simple voxel raycasting engine in SFML with multithreading support
A program to align and stack astronomical images.
fill a selection according to neighboring gradient area