Mons Rümker (40.8°N, 302.01°E) at dawn, means the Moon was nearly Full the night of December 28-29, 2009. The 72 km-wide volcanic heap lords it over the north-northwest Oceanus Procellarum and is never seen except in profile from Earth. Mosaic (by Microsoft ICE) from four LROC Wide Angle Camera observations (processed using LROC WAC Previewer v.1.6) over LRO orbits 2329-2332; avg. alt. 46.59 km., avg. res. 65.53 m, avg. LRO/Moon/Sun phase angle = 89.07° See larger view HERE [NASA/GSFC/Arizona State University]
Nearly a full lunar day later, late in a lunar afternoon, January 11, 2010, Rümker was fully illuminated perhaps for another 20 hours or so. Although, at middle latitudes north, areas behind the higher elevations have already fallen into long shadows as the Sun creeps down to within ten degrees of the southwest horizon. On Earth, the Moon is rising as a waning crescent before dawn. Another mosaic (by Microsoft ICE) from four LROC WAC passes in LRO orbits 2504-2507 (processed using LROC WAC Previewer v.1.6); avg. alt. 40.44 km., avg. res. 57.05 m, avg. LRO/Moon/Sun phase angle = 80.26° See larger view HERE [NASA/GSFC/Arizona State University].
Part of a spectacular HDTV view from Japan's Kaguya lunar orbiter in 2008 shows Rümker at dawn from 100 km polar orbit. [JAXA/NHK/SELENE].
Simulated view of Rümker from a point of view 8000 meters over the average -2200 meter elevation of this part of the Procellarum plain. The wide mound shows extensive signs of periodic intrusions of material piling over 900 meters above its surroundings, though most of the 72 km-wide feature is only 500 m high.