The Lunar Equator

The equator of the Moon is defined by its rotational axis. It is the great circle contained by the plane that is perpendicular to the line connecting the north and south poles of the Moon.

Map of the Moon (nearside) with selenographic coordinate lines (latitude and longitude)

Here is a list of named lunar features through which the Moon’s equator passes, from lunar east to lunar west on the part of the Moon visible from the Earth.

Remember, lunar longitude is opposite the direction in the sky. East longitude is the west/right side of the moon, and west longitude is the east/left side of the moon as viewed from the northern hemisphere of the Earth.

The diameter of each feature is included, followed by the depth of the feature, where available.

Crater Wyld
Wyld
Center: 98.101˚ E, 1.416˚ S
Range: 96.395˚ - 99.806˚ E, 3.121˚ S - 0.289˚N
Crater; libration zone
58 mi
James Hart Wyld (1913-1953), American rocket engineer
Wrinkle ridge Dorsum Cloos
Dorsum Cloos
Center: 90.410˚ E, 1.149˚ N
Range: 90.387˚ - 91.144˚ E, 0.268˚ S - 2.576˚ N
Wrinkle ridge; libration zone
64 mi
Hans Cloos (1885-1951), German geologist
Mare Smythii, “Smyth’s Sea”
Mare Smythii
Center: 87.049˚ E, 1.709˚ S
Range: 80.941˚ - 92.719˚ E, 7.456˚ S - 4.496˚ N
Mare; libration zone; Smyth's Sea
232 mi, 3.1 mi
William Henry Smyth (1788-1865), English naval officer and astronomer
Craters Schubert J, Jenkins, Schubert X, and Nobili
Schubert J
Center: 78.935˚ E, 0.012˚ S
Range: 78.579˚ - 79.292˚ E, 0.344˚ S - 0.320˚ N
Crater
12 mi
Friedrich Theodor von Schubert (1758-1825), German astronomer & geographer 
Jenkins
Center: 78.041˚ E, 0.372˚ N
Range: 77.418˚ - 78.663˚ E, 0.251˚ S - 0.994˚ N
Crater
24 mi, 1.9 mi
Louise Freeland Jenkins (1888-1970), American astronomer
Schubert X
Center: 76.750˚ E, 0.310˚ N
Range: 75.940˚ - 77.561˚ E, 0.501˚ S - 1.121˚ N
Crater
32 mi
Friedrich Theodor von Schubert (1758-1825), German astronomer & geographer
Nobili
Center: 75.949˚ E, 0.166˚ N
Range: 75.260˚ - 76.638˚ E, 0.523˚ S - 0.855˚ N
Crater
26 mi, 2.4 mi
Leopoldo Nobili (1784-1835), Italian physicist
Craters Maclaurin X and Maclaurin O
Maclaurin X
Center: 68.708˚ E, 0.091˚ N
Range: 68.403˚ - 69.014˚ E, 0.214˚ S - 0.397˚ N
Crater
15 mi
Colin Maclaurin (1698-1746), Scottish mathematician
Maclaurin O
Center: 67.557˚ E, 0.135˚ S
Range: 66.873˚ - 68.241˚ E, 0.819˚ S - 0.548˚ N
Crater
23 mi
Colin Maclaurin (1698-1746), Scottish mathematician
Mare Spumans, “The Foaming Sea”
Mare Spumans
Center: 65.303˚ E, 1.302˚ N
Range: 63.613˚ - 66.733˚ E, 1.062˚ S - 3.722˚ N
Mare
87 mi
The Foaming Sea
Crater Webb C
Webb C
Center: 63.833˚ E, 0.149˚ N
Range: 63.267˚ - 64.398˚ E, 0.247˚ S - 0.544˚ N
Crater
21 mi
Thomas William Webb (1807-1885), English astronomer
Sinus Successus, “Bay of Success”
Sinus Successus
Center: 58.520˚ E, 1.124˚ N
Range: 56.519˚ - 60.188˚ E, 0.861˚ S - 2.872˚ N
Bay
82 mi
Bay of Success
Mare Fecunditatis, “Sea of Fertility”
Mare Fecunditatis
Center: 53.669˚ E, 7.835˚ S
Range: 40.771˚ - 63.340˚ E, 21.695˚ S - 6.112˚ N
Mare
429 mi, 1.1 mi
Sea of Fertility
Craterlet Taruntius P is on the left (Taruntius K is at right)
Taruntius P
Center: 51.585˚ E, 0.060˚ N
Range: 51.473˚ - 51.696˚ E, 0.051˚ S - 0.172˚ N
Craterlet
5 mi, 0.9 mi
Lucius Tarutius Firmanus (fl. 86 B.C.), Roman philosopher, mathematician, and astrologer
Wrinkle ridge Dorsum Cayeux, with craterlets Taruntius P (left) and Taruntius K (right) in the lower left
Dorsum Cayeux
Center: 51.220˚ E, 0.763˚ N
Range: 50.922˚ - 52.000˚ E, 0.598˚ S - 2.113˚ N
Wrinkle ridge
59 mi
Lucien Cayeux (1864-1944), French sedimentary petrographer
Wrinkle ridges Dorsa Cato (north is to the right in this Apollo 11 view)
Dorsa Cato
Center: 47.701˚ E, 0.213˚ N
Range: 46.605˚ - 49.599˚ E, 1.165˚ S - 2.233˚ N
Wrinkle ridges
87 mi
Marcus Porcius Cato (234-149 B.C.), Roman soldier, senator, and historian
Rille Rima Messier
Rima Messier
Center: 44.545˚ E, 0.756˚ S
Range: 43.357˚ - 45.581˚ E, 1.561˚ S - 0.015˚ N
Rille
62 mi
Charles Messier (1730-1817), French astronomer
Crater Lubbock R
Lubbock R
Center: 40.453˚ E, 0.167˚ S
Range: 40.060˚ - 40.845˚ E, 0.559˚ S - 0.225˚ N
Crater
15 mi
Sir John William Lubbock (1803-1865), English banker, barrister, mathematician, and astronomer
Maskelyne T & Maskelyne A (click on image for higher resolution view)
Maskelyne T
Center: 36.593˚ E, 0.040˚ S
Range: 36.507˚ - 36.678˚ E, 0.125˚ S - 0.046˚ N
Craterlet
3 mi
Nevil Maskelyne (1732-1811), English astronomer
Maskelyne A
Center: 34.089˚ E, 0.032˚ N
Range: 33.603˚ - 34.574˚ E, 0.453˚ S - 0.517˚ N
Crater
18 mi
Nevil Maskelyne (1732-1811), English astronomer
Mare Tranquillitatis, “Sea of Tranquility”
Mare Tranquillitatis
Center: 30.835˚ E, 8.349˚ N
Range: 16.924˚ - 45.490˚ E, 4.051˚ S - 19.375˚ N
Mare
544 mi
Sea of Tranquility
Rimae Hypatia (two rilles)
Rimae Hypatia
Center: 22.777˚ E, 0.340˚ S
Range: 19.690˚ - 25.975˚ E, 1.406˚ S - 0.672˚ N
Rilles
128 mi
Hypatia (c.370-415), Alexandrian philosopher, mathematician, and astronomer
Craters Lade A and Lade B
Lade A
Center: 12.726˚ E, 0.161˚ S
Range: 11.773˚ - 13.680˚ E, 1.114˚ S - 0.793˚ N
Crater
35 mi
Heinrich Eduard von Lade (1817-1904), German banker and amateur astronomer
Lade B
Center: 9.796˚ E, 0.016˚ N
Range: 9.412˚ - 10.180˚ E, 0.368˚ S - 0.399˚ N
Crater
15 mi
Heinrich Eduard von Lade (1817-1904), German banker and amateur astronomer
Craters Rhaeticus F, Rhaeticus, and Rhaeticus L
Rhaeticus F
Center: 6.438˚ E, 0.060˚ S
Range: 6.134˚ - 6.742˚ E, 0.364˚ S - 0.244˚ N
Crater
11 mi
Georg Joachim Rheticus (1514-1574), Austria-born astronomer & mathematician
Rhaeticus
Center: 4.924˚ E, 0.032˚ N
Range: 4.192˚ - 5.657˚ E, 0.701˚ S - 0.764˚ N
Crater
30 x 27 mi, 1.0 mi
Georg Joachim Rheticus (1514-1574), Austria-born astronomer & mathematician
Rhaeticus L
Center: 3.484˚ E, 0.205˚ N
Range: 3.257˚ - 3.711˚ E, 0.022˚ S - 0.432˚ N
Crater
9 mi
Georg Joachim Rheticus (1514-1574), Austria-born astronomer & mathematician
Sinus Medii, “Bay of the Center”; this feature is closest to the center of the Moon as seen from Earth
Sinus Medii
Center: 1.027˚ E, 1.634˚ N
Range: 3.371˚ W - 5.551˚ E, 2.048˚ S - 4.641˚ N
Bay
178 mi
Bay of the Center
Crater Mösting E
Mösting E
Center: 4.591˚ W, 0.178˚ N
Range: 5.189˚ - 3.992˚ W, 0.421˚ S - 0.777˚ N
Crater
27 mi
Johan Sigismund von Møsting (1759-1843), Danish banker, finance minister, and astronomy enthusiast
Crater Sömmering
Sömmering
Center: 7.526˚ W, 0.193˚ N
Range: 7.987˚ - 7.065˚ W, 0.268˚ S - 0.654˚ N
Crater
17 mi, 0.8 mi
Samuel Thomas von Sömmering (1755–1830),German physician and anatomist
Crater Lansberg
Lansberg
Center: 26.627˚ W, 0.312˚ S
Range: 27.266˚ - 25.988˚ W, 0.951˚ S - 0.327˚ N
Crater
24 mi, 1.9 mi
Philippe van Lansbergen (1561-1632), Dutch astronomer and mathematician
Mare Insularum, “Sea of Islands”
Mare Insularum
Center: 30.640˚ W, 7.792˚ N
Range: 39.195˚ - 22.153˚ W, 0.596˚ S - 16.345˚ N
Mare
318 mi
Sea of Islands
Oceanus Procellarum, “Ocean of Storms”
Oceanus Procellarum
Center: 56.677˚ W, 20.671˚ N
Range: 81.084˚ - 26.850˚ W, 16.266˚ S - 57.433˚ N
Mare
1611 x 353 mi
Ocean of Storms
Crater Lohrmann D cut through by one of the rilles of Rimae Hevelius (arrow points to another part of Rimae Hevelius)
Lohrmann D
Center: 65.273˚ W, 0.141˚ S
Range: 65.442˚ - 65.104˚ W, 0.310˚ S - 0.028˚ N
Crater
7 mi
Wilhelm Gotthelf Lohrmann (1796-1840), German selenographer
Rimae Hevelius
Center: 66.377˚ W, 0.809˚ N
Range: 67.849˚ - 63.582˚ W, 1.284˚ S - 2.956˚ N
Rilles
113 mi
Johannes Hevelius (1611-1687), Polish astronomer
Crater Lohrmann
Lohrmann
Center: 67.383˚ W, 0.440˚ S
Range: 67.898˚ - 66.867˚ W, 0.955˚ S - 0.075˚ N
Crater
19 mi, 1.0 mi
Wilhelm Gotthelf Lohrmann (1796-1840), German selenographer
The lunar equator crosses the rilles of Rimae Riccioli just south of craters Riccioli C and Riccioli H.
Rimae Riccioli
Center: 73.071˚ W, 1.515˚ S
Range: 76.809˚ - 68.566˚ W, 4.754˚ S - 1.247˚ N
Rilles
249 mi
Giovanni Battista Riccioli (1598-1671), Italian astronomer
Crater Schlüter P
Schlüter P
Center: 85.208˚ W, 0.054˚ N
Range: 85.550˚ - 84.865˚ W, 0.289˚ S - 0.397˚ N
Crater; libration zone
12 mi
Heinrich Schlüter (1815-1844), German astronomer

Now that we’ve taken a tour of nearside features along the equator, let us turn to the lunar north and south celestial poles. As you know, the Earth’s north celestial pole (NCP) is currently located quite close to Polaris. However, on the Moon, the NCP is located in Draco near the Cat’s Eye Nebula (NGC 6543), about two-thirds of the way between Polaris and the center of the Head of Draco.

The Moon’s NCP is located near the Cat’s Eye Nebula (NGC 6543), a fine planetary nebula in Draco.

The Moon’s south celestial pole (SCP) is located in the constellation Dorado inside of the Large Magellanic Cloud (LMC). If you were stationed at the south pole of the Moon, you would see the Large Magellanic Cloud directly overhead at all times!

The Moon’s SCP is located in the constellation Dorado within the Large Magellanic Cloud.

The Moon has many fascinating places, tempting us to explore. Some of them have quite interesting names. One of my favorites is Lacus Perseverantiae, Lake of Persistence. Its location is 62.0˚ E and 8.0˚ N. See if you can find it here. (Hint: under Layers : Overlays select Nomenclature, and under Settings select Show Graticule.) Have fun exploring!

References

Cocks, Elijah E.; Cocks, Josiah C. (1995). Who’s Who on the Moon: A Biographical Dictionary of Lunar Nomenclature. Tudor Publishers. ISBN978-0-936389-27-1.

1:1 Million-Scale Maps of the Moon, IAU/USGS/NASA. https://planetarynames.wr.usgs.gov/Page/Moon1to1MAtlas.

Virtual Moon Atlas 6.0 Pro. Computer software. https://ap-i.net/avl/en/start.

Leave a Reply

Your email address will not be published.