Peary (crater)

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Crater characteristics
Coordinates	88.6° N, 33.0° E
Diameter	73 km
Depth	Unknown
Colongitude	25° at sunrise
Eponym	Robert Peary

Peary is the closest large crater to the lunar north pole. At this latitude the crater interior receives little sunlight, and parts of the southern floor remain permanently cloaked in shadow. From the Earth the crater appears on the northern lunar limb, and is seen from the side.

The crater is nearly circular, with an outward bulge along the northeast rim. There is a gap in the southwest rim, where it joins a slightly smaller worn crater formation. The outer rim of Peary crater is worn and eroded, creating a rugged mountainous ring that produces long shadows across the crater floor.

The crater floor is relatively flat, but marked by several small craterlets, particularly in the eastern half. The southern third of the interior remains cloaked in shadows, and so its features can not be readily discerned.

The worn and lava-flooded crater Byrd lies close to the southern rim of Peary. To the northwest, about a fourth the way around the lunar pole, is the larger Hermite crater. On the opposite side of the pole, on the far side of the moon, lies the still-larger Rozhdestvenskiy crater.

In 2004, a team led by Dr. Ben Bussey of Johns Hopkins University using images taken by the Clementine mission determined that four mountainous regions on the rim of Peary crater appeared to remain illuminated for the entire Lunar day. These unnamed "mountains of eternal light" are possible due to the Moon's extremely small axial tilt, which also gives rise to permanent shadow at the bottoms of many polar craters. No similar regions of eternal light exist at the less-mountainous south pole. Clementine's images were taken during the northern Lunar hemisphere's summer season, and it remains unknown whether these four mountains are shaded at any point during their local winter season.

The northern rim of the Peary crater is considered a likely site for a future Moon base due to this steady illumination, which would provide both a relatively stable temperature and an uninterrupted solar power supply. It is also near permanently shadowed areas that may contain some quantity of frozen water.