Mercury by David Gray 1995 and 1996. The terminator of Mercury shows fairly frequent irregularities. Such appearances are undoubtedly caused by the presence of contrasting regions on the disc. On 1995 May 13 Ian Phelps drew one such instance. The cusps also display interesting appearances.
Mercury looms out of the evening sky.
Mario Frassati recently recorded a dark aspect to the south cusp of Mercury . Solitudo Martis, Solitudo Lycaonis, and Solitudo Admetei. And by contrast, Richard Baum rendered these views of an unusually bright aspect to Mercury's cusp regions. Other unusual effects are sometimes noted, such as cusp extensions that are difficult to explain for this almost airless world, as seen in this rare observation by the experienced inner planetary observer, R W Middleton. Mercury is paid much less attention than it deserves, but these pages surely show that it is a world of varied telescopic aspects, despite the difficulties in observing it.