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 its name. In Ancient Rome, as one of the four Agonalia, this day in honor of Sol Indiges was held on December 11, as was Septimontium. Dies natalis (birthday) was held at the temple of Tellus on December 13, Consualia was held on December 15, Saturnalia was held December 17–23, Opiconsivia was held on December 19, Divalia was held on December 21, Larentalia was held on December 23, and the dies natalis of Sol Invictus was held on December 25. These dates do not correspond to the modern Gregorian calendar. The Anglo-Saxons referred to December–January as Ġēolamonaþ (modern English: "Yule