Image of the Marius Hills in Oceanus Procellarum.
These volcanic domes are the highest concentration of volcanic features on the near-side of the moon and are a highly anomalous landform on the lunar surface, since most lunar volcanism is caused by highly fluid mare basalt that spreads out to form flood basaltic plains (the solidified basaltic seas or mares on the moon), rather than elevated volcanic domes.
Spread across some 35,000 square kilometres, these domes, cones, ridges and rilles lie on an elevated plateau which rises several hundred metres up to 2 km above the basalts of Oceanus Procellarum. Comprising some 262 low domes and steep-sided domes, 59 cones and some 20 rilles and ridges, the 135 low domes range from 50-200m in elevation with a maximum diameter of 25km, whilst the 127 steep-sided domes range from 200-500m elevation and 2-15km diameter range (Huang et al. 2011, Journal of Earth Science).
These domes are best imaged around 2 days before the full moon, when the Marius Hills lie along the terminator (i.e. the line separating illuminated from dark areas of the moons surface, i.e. local sunrise or local sunset). It is at this time (which was local sunrise on the Marius Hills) that the longest possible shadows are created by this low pimpled terrain, which enhances its definition.
A recently discovered skylight at Marius Hills (about 65m in diameter and too small to be visible in this image where resolution is about 1-1.5 km) is of research interest in the field of lunar settlement. “Lava tubes might be useful as locations for lunar bases. The interiors of lava tubes could protect human explorers from different aspects of the lunar environment, including cosmic rays, meteorite impacts, and the extreme temperature differences between the lunar day and night. Just like caves on the Earth, lunar caves, including lava tubes, have temperatures that are constant”. (LROC website).
Skywatcher 8 inch/f5 Newtonian, Televue 5X Powermate, ASI1600mm Pro, ZWO red filter.
Imaged from Seacliff, Adelaide, 6 November 2022.
Waxing gibbous lunar surface 96% illuminated.