Redshift is a group of educational planetarium and astronomy software packages that allow the user to observe the sky from a range of dates, print off data based on the observations and (in some versions) control a telescope. It uses data from the Hubble Guide Star Catalog II. Began in the early 1990s, the current version is 8 (released in 2012), which includes 3D models of the galaxy, multimedia tours and access to star catalogs. Platforms include Windows (8/7/Vista/XP(SP2)), Mac, iPhone and iPad, PC editions include Premium (with a library of 100 million objects and telescope control) and Compact (fewer objects in the library, no telescope interface). All versions support Redshift-live links – an online site to share observation information and other astronomy pictures and data.