The Moon

The brightest sights are the easiest to begin with. The Moon shows at least as much detail in binoculars as Galileo saw with his primitive telescopes. The mountains, craters, and plains he discovered in 1609 established that the Moon is an ordinary world, like the Earth, overturning the long-established belief that it was a perfect sphere made of some heavenly substance.

The first glance through binoculars reveals the major dark areas, the so-called seas or maria (plural of the Latin word for sea, mare, pronounced MAH-ray). The maria are flat lava plains. After you spend a few nights outdoors identifying the Moon's features, its geography will begin to grow as familiar as that of the Earth.

When the Moon is a waxing crescent in the western evening sky a couple of days after new, only Mare Crisium is visible. The terminator, the line dividing lunar day and night, moves across the disk to unveil ever more features as the Moon's phase grows to first quarter, gibbous, then full. Night by night more seas are revealed — Mare Tranquillitatis, Serenitatis, Imbrium, and finally Oceanus Procellarum. Near the terminator the slanting sunlight casts long shadows, so here mountains and valleys stand out prominently. They become more easily visible if you brace the binoculars tightly against something to hold them very still.