Planetarium dome projection
The
fisheye and spherical mirror distortion features allow Stellarium to be
projected onto domes. Spherical mirror distortion is used in
projection systems that use a digital video projector, and a first surface convex spherical mirror to project images onto a dome. Such systems are generally cheaper than traditional planetarium projectors and fish-eye lens projectors and for that reason are used in budget and home planetarium setups where projection quality is less important.