History of radar for various purposes; on the Shuttle Radar Topography Mission, the entire planet was mapped at a 30-m resolution. The Jodrell Bank Observatory, an operation of the University of Manchester in Britain, was originally started by Bernard Lovell to be a radar astronomy facility. It initially used a war-surplus GL-II radar system operating at 71 MHz (4.2 m). The first observations were of ionized trails in the Geminids meteor shower during December 1945. While the facility soon evolved to become the third largest radio observatory in the world, some radar astronomy continued. The largest (250-ft or 76-m in diameter) of their
December 21 December 22, unless that date is a Sunday, in which case it's moved to the 23rd: December 22 "'Last Saturday before Christmas: December 22" Sunday before Christmas: December 23 December 26, unless that day is a Sunday, in which case the 27th: December 26 Last Friday before Christmas: December 28 Sunday after Christmas: December 30 December December is the twelfth and final month of the year in the Julian and Gregorian Calendars and is the seventh and last of seven months to have a length of 31 days. December got its name from the Latin word "decem" (meaning ten)