June 2016’s Waning Gibbous Moon Shows Mare Nubium in Lunar Southwest

Summary: June 2016’s waning gibbous moon, from Tuesday, June 21, to Sunday, June 26, shows Mare Nubium in the lunar southwest.

Mare Nubium’s lunar location; image taken by Clementine spacecraft March 15, 1994: NASA, Public Domain, via NASA

June 2016’s waning gibbous moon, waning from Tuesday, June 21, to Sunday, June 26, shows Mare Nubium in the lunar southwest. The lunar southwest lies in the lower quarter of the left half of the moon’s near side.

Mare Nubium is visible to unaided eyes in the Northern Hemisphere during the moon’s full, waning and last quarter phases. During the waning and last quarter phases of the lunar cycle, the left half of the moon is illuminated for moon watchers in the Northern Hemisphere’s temperate and high latitudes.

The moon's full phase is not necessarily the best phase for aided viewing of Mare Numbium and other lunar features. A moon filter is recommended to counter the full moon's extreme brightness. Topographic contrasts are more dramatic in other phases.

After turning full Monday, June 20, at 7:02 a.m. Eastern Daylight Time (11:02 Coordinated Universal Time), June 2016’s moon then begins decreasing its illumination, or waning. As the sixth phase in the eight-phase lunar cycle, the waning gibbous moon features more than 50 percent illumination of the lunar disk, from an Earth-based perspective.

Moonrise times span super late evening to early morning for June 2016’s waning gibbous moon. The waning gibbous moon rises Tuesday, June 21, at 11:33 p.m. EDT (03:33 UTC); Thursday, June 23, at 12:33 a.m. EDT (04:33 UTC); Friday, June 24, at 1:34 a.m. EDT (05:34 UTC); Saturday, June 25, at 2:33 a.m. EDT (06:33 UTC); Sunday, June 26, at 3:32 a.m. EDT (07:32 UTC).

Moonset times span afternoon hours for June 2016’s waning gibbous moon. The waning gibbous moon sets Wednesday, June 22, at 2 p.m. EDT (18:00 UTC); Thursday, June 23, at 2:43 p.m. EDT (18:43 UTC); Friday, June 24, at 3:22 p.m. EDT (19:22 UTC); Saturday, June 25, 3:56 p.m. EDT (19:56 UTC); Sunday, June 26, at 4:28 p.m. EDT (20:28 UTC).

Mare Nubium numbers among the dark areas of the moon that are known singularly as mare and plurally as maria. These dark features derive their name from the Latin word for “sea.”

Lunar maria are actually flat, low-elevation plains. Lunar maria cover approximately 16 percent of the lunar surface. Mare Nubium measures a diameter of 714.5 kilometers (443.96 miles).

Binoculars and telescopes reveal specifics of Mare Nubium’s location on the lunar surface. The dark feature is sited east of the vast Oceanus Procellarum and west of the densely cratered Southern Highlands.

Tycho, a bright, young impact ray crater in the Southern Highlands, lies south of Mare Nubium. Tycho’s diameter measures 86 kilometers (53.43 miles). A prong of Tycho’s rays of impact-ejected materials frames Bullialdus crater in Mare Nubium’s western part.

Pitatus crater is found at Mare Nubium’s southern edge. The ancient impact crater’s northwestern well displays heavy wear. A narrow cleft in the wall joins Pitatus with Hesiodus, a smaller lunar crater. Pitatus has a diameter of 100.63 kilometers (62.54 miles).

Rupes Recta (Latin: “Straight Cliff”) is a linear fault, known as a rille, in the southeastern Mare Nubium. Commonly called the Straight Wall, has a length of 115.95 kilometers (72.04 miles).

Jesuit astronomer Giovanni Battista Riccioli (April 17, 1598-June 25, 1671) developed a systematic approach to lunar nomenclature. He gave the Latin name to the dark, prominent feature in the near side’s southwestern sector. Mare Nubium translates as “Sea of Clouds.”

The Jesuit astronomer selected Bulldialdus as the Latinized form of the crater’s namesake, French cleric astronomer Ismaël Boulliau (Sept. 28, 1605-Nov. 25, 1694). Hesiodus is named after Hesiod, an ancient Greek epic poet whose works usually are placed in the 8th and/or 7th century BCE (Before Common Era). Sixteenth-century Italian astronomer and mathematician Pietro Pitati is Pitatus crater’s namesake. Tycho crater honors Danish astronomer and nobleman Tycho Brahe (Dec. 15, 1546-Oct. 24, 1601).

The takeaway for the showing of dark Mare Nubium by June 2016's waning gibbous moon is the lunar disk's easy, unaided visibility that encourages deeper familiarity via binoculars and telescopes.

Bullialdus, Hesiodus and Pitatus craters in Mare Nubium, published May 1964 by U.S. Air Force Aeronautical Chart and Information Center: U.S. Air Force and NASA, Public Domain, via US Geological Survey Gazetteer of Planetary Nomenclature; Universities Space Research Association (USRA) Lunar and Planetary Institute (LPI)

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Mare Nubium’s lunar location; image taken by Clementine spacecraft March 15, 1994: NASA, Public Domain, via NASA @ http://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/lroc_20090702_a.html

Bullialdus, Hesiodus and Pitatus craters in Mare Nubium, published May 1964 by U.S. Air Force Aeronautical Chart and Information Center: U.S. Air Force and NASA, Public Domain
Available via US Geological Survey Gazetteer of Planetary Nomenclature @ http://planetarynames.wr.usgs.gov/Page/Moon1to1MAtlas
Available via Universities Space Research Association (USRA) Lunar and Planetary Institute (LPI) @ http://www.lpi.usra.edu/resources/mapcatalog/LAC/lac94/

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