MoonWatch
August 1998
Copernicus - The "Monarch of the Moon"
Map of Copernicus by Philip Fauth (1900)
On the evening of August 1, as the Moon's sunrise terminator sweeps across its western hemisphere, keen-sighted naked eye observers may notice a slight irregularity near the centre of the terminator. The broad eastern flanks of the spectacular 93 km diameter crater Copernicus are being illuminated by the rising Sun.
Through a telescope the intricacies of Copernicus' inner and outer walls are impressive. A 60 mm refractor x 100 will provide a breathtaking visual scene, with the concentric ridges lying close to Copernicus' rim giving way to radial hummocks further away. 50 km south of Copernicus' rim lies the l5 km long keyhole-shaped crater Fauth, named after the German selenographer Philip Fauth (1867-1941) who made some accurate and detailed visual maps of the Moon.
By the evening of August 2 the terminator will have moved a couple of hundred kilometres further west, showing Copernicus in all its majesty. The mighty system of ridges and furrows surrounding the "Monarch of the Moon" radiate outwards for more than 100 km, leading on to the spectacular system of rays that trace over lunar mare and hill to distances up to 600 km. During full moon of August 8, take a look at the fully illuminated Copernicus and its impressive ray system. The last chance to view Copernicus this lunation is during the early hours of August 16, when the lunar evening terminator is encroaching from the east about 100 km from Copernicus. This is an ideal opportunity to compare the Copernican sunset with sunrise.
