09.Mairan

On the chart: From the north-east, a highland protrudes into Oceanus Procellarum and to the west borders the Bay of the Rainbow. (see chart 10) North of Gruithuisen we see a group of hills. One of the hills, Gruithuizen Gamma is a high lunar dome with a diameter of about 19 km, with, at the top a small crater (2 km ø ).

DELISLE - Joseph-Nicolas Delisle (4 April 1688, Paris, France - 11 September 1768, Paris, France) French astronomer and cartographer. From 1725-1747 Director of the New Petrograd Observatory. Discovered a new method of calculating the distance from the Earth to the Sun, using the solar transits of the planets Mercury and Venus.

Crater. (25 km /15Mi ø ) (Dept: 2,550m /7,700 ft) (29°54′ N, 34°36′ W) Isolated circular formation. Steep slopes to the South. High walls. Eroded floor. Central mountains.

GRUITHUISEN - Franz von Gruithuisen (1774 - 1852) German astronomer and physician. Persistent but stubborn observer, author of a book on the inhabitants of the moon, and the buildings he claimed he saw on the Moon. First to suggest that craters on the Moon were caused by meteorite impacts.

Crater (16 km /10 Mi ø ) (Dept: 1,860 m) (32.9°N, 39.7°W) Isolated circular formation. Steep slopes. High walls. Extensive flat floor.

MARE IMBRIUM - Sea of Rains. Named by Giovanni Battista Riccioli in 1651. (Riccioli's Moon Map)

Mare (1,145 km / 711 Mi ø ) (830.000 km² ) (32.8°N, 15.6°W) Second largest lunar sea. Very flat floor with numerous wrinkle ridges at the periphery. Contains the 1st discovered Mascon.

LOUVILLE - Jacques d'Allonville, Chevalier de Louville (1671 - 1732) French Astronomer and Mathematician. Noted for determining a method for precisely calculating the occurrence of solar eclipses.

Crater (24 x 36 km /15 x 22 Mi ø ) (Dept: 1,000m /3,000ft) (44.0°N, 46.0°W) Eroded crater. Elongated shape. Steep slopes supporting many craterlets. Jumbled and dark floor. Narrow grooves.

MAIRAN - Jean J. d'Ortous de Mairan (Born: Béziers, France, 1678 - Died: Paris, France, 1771) French astronomer. Studied Aurora borealis. 
Works on pendulums, and Earth /Moon movements. Author of the "Historical and physical Treaty of the boreal aurorae" in 1733. Secretary of the French Academy of Sciences in 1740.

Crater (41 Km /24Mi ø ) (Dept: 3,400 m /10,300 ft) (41.6° N, 43.4° W) Circular crater with sharp edges. Steep slopes riddled with craterlets. High walls in light terraces. Flat and wide floor. Small central mountain. Craterlets and hills.

OCEANUS PROCELLARUS - Ocean of Storms. Named by Giovanni Battista Riccioli in 1651. (Riccioli's Moon Map)

Mare  (4,000,000 km² /1,500,000 Mi² ) (18.4° N, 57.4° W) Largest lunar sea. (North-South axis: 2,592 km /1,611 mi) Very flat to the center. (80 m altitude difference in a 400 km diameter circle).

SINUS RORIS - Sinus Roris (Latin for "Bay of Dew") is an extension of the northern edge of Oceanus Procellarum on the Moon.

Bay (202 km /125.5 Mi ø ) (54.0° N, 56.6° W) Very flat Region uniting Mare Frigoris and Oceanus Procellarum.
  

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