The Lunar Terminator

Viewing the full Moon for the first time through a newly acquired telescope has probably been a huge disappointment to many a budding lunar observer. The novice soon realizes that the most efficient way to gain insights into our neighbor’s landscape is to spend time instead at that ever-transitional region of relentlessly moving shadow, where night turns to day, and vice versa, before or after a full Moon. This is the region of the lunar terminator, where lunar observations are most telling and rewarding. It soon becomes evident that most of our lunar observing should take place here, or at least nearby. The dramatically exaggerated appearance of even the most minimally vertical of lunar features is one of the most amazing optical effects you may ever see. The stark elongated shadows, not muted by the presence of an atmosphere, provide dramatic views of the lunar surface.

You already know that the lunar landscape is nothing like the impressions you may have had of jagged and sharp features thrusting high into the surrounding space. Look again at the view of the lunar limb in Fig. 6.1, Chap. 6, and any ongoing impressions about such features will soon vanish! However, by maintaining true perspective it is possible to gain quick and direct insight into our neighboring world, one we are witnessing from such remarkably close proximity. With such detail so startlingly clarified, there is hardly anything we can observe in space that offers so much in so little time. In just half an hour we can see and appreciate more detail on the Moon than we can accomplish in an entire night with any other subject, or group of subjects.