SkOP (Sky Orthographic Projector) is an openGL viewer that displays
sky maps projected on a zoomable, rotating virtual globe.

It performs a direct hardware-accelerated projection of the data on
the sphere. This allows the handling of data at full-resolution,
interactive change of the color scale, and fast switching between
different maps.  It accepts maps in the HEALPix pixelization format
(http://healpix.jpl.nasa.gov/index.shtml) stored in FITS files.

SkOP is designed with the exploitation of Cosmic Microwave Background
data in mind. For example, the WMAP Space mission data are made
available at:
http://lambda.gsfc.nasa.gov/product/map/dr3/m_products.cfm