TOP TIP! On the morning of 26 August, the lunar morning terminator will be encroaching upon Eratosthenes, with the crater making for a splendid sight. A Moon filter will improve contrast, toning down any glare that washes out intricate features of the lunar surface.
E ratosthenes is a 59-kilometre (37-mile) wide crater located at the western end of the majestic curved sweep of the lunar Apennine Mountains (Montes Apenninus) on the southern shore of Mare Imbrium (Sea of Rains). This magnificent crater, set among a splendid mountain backdrop, is often overlooked by virtue of its proximity to the larger crater Copernicus, which is 93 kilometres (58 miles) wide and lies less than 300 kilometres (186 miles) to the southwest of Eratosthenes, so is often visible at the same time. However, Eratosthenes itself is such a spectacular feature when illuminated by a morning or evening Sun that its topography is delightful through mid to high magnifications.