Ina (crater)

Ina

Ina seen by Lunar Reconnaissance Orbiter. Small crater at lower left is Osama, at upper left ‒ Dag; the biggest hill in right part of Ina is Mons Agnes. Image width is 3.5 km
Coordinates	18°40′N 5°18′E / 18.66°N 5.30°E / 18.66; 5.30Coordinates: 18°40′N 5°18′E / 18.66°N 5.30°E / 18.66; 5.30
Diameter	2.9×1.9 km
Depth	64 m
Eponym	Latin female name Ina

Ina is a peculiar small depression ("crater" in IAU nomenclature) on the Moon, in Lacus Felicitatis. It is D-shaped, 2.9×1.9 km wide and 64 m deep (from the deepest point of the bottom to the highest point of the rim).

Ina is remarkable for several dozens of low hills with flat or rounded tops and very sharp rounded boundaries, looking like drops of mercury. Their surface looks like usual surface of the Moon, and the space between them is strongly different. Ina is the most prominent of several dozens of similar features on the Moon. Their origin is unclear.

Ina was discovered on photographs taken in 1971 by the Apollo 15 crew from lunar orbit. It could have been found 5 years earlier, on images by Lunar Orbiter 4, but a photographic flaw prevented this. At the end of 1972 it was observed and photographed by the Apollo 17 crew. Later it was explored by orbiting spacecraft. Beginning in 2009, Lunar Reconnaissance Orbiter obtained photos of Ina with resolution of about 0.5 m/pixel and with varying illumination angles.

In 1974 on a topophotomap, published by NASA, this feature was given the Latin female name Ina, according to a tradition to give small lunar craters first human names. In 1979 this name was adopted by International Astronomical Union. The feature is also called D-caldera in Apollo-era publications due to its shape, and at the time it was believed to be a unique feature on the moon.

Two neighbouring features were named together with Ina in 1976. They are small craters Osama on its southwestern edge and Dag to the northwest (both 400 m in diameter). The widest hill in the eastern part of Ina (650 m wide) is named Mons Agnes (named in 1979).