18.Aristarchus

This part of Oceanus procellarum the Schröter valley, the extended rilles of Rima Marius and Rima Aristarchus. Herodotus Omega is a lunar dome, of which we find a group near Marius (See chart 29). Prominent on chart 18, the bright crater Aristarchus with its ray system.

ARISTARCHUS - Aristarchus of Samos. (Ἀρίσταρχος). (About: 320-250 BC) Greek astronomer. Tried as first one to use triangulation to measure the distance to the Sun and the Moon, and taught (According to Plutarch) that Earth  is in an orbit around the Sun, and turns around it's axel.

Walled plain (40 Km /24.9 Mi ø¸ ) (Depth: 3.7 km /2.3 Mi) (23.7°N, 47.4°W) Very bright crater with bright rays, bright enough to be visible to the naked eye from Earth.

HERODOTUS - Herodotos (Ἡρόδοτος). (About: 484 -425 BC) Greek.  First historian, and inventor of the word "History" used in this way.

Crater. (35 km /21 Mi ø¸ ) (Depth: 1.5 km /4,921 ft) (23.2° N, 49.7° W)  Dark, lava flooded floor, small craterlet overlapping the northwest rim.

OCEANUS PROCELLARUS - See Map 19.

RIMA MARIUS - Simon Mayer. (1570 - 1624) German astronomer, on of the first who used a telescope. Discovered the Andromeda Nebula, and must have seen the moons of Jupiter, for he gave them their present names.

Rima (Rille). (Length: 250 km /155 Mi) (Width: 500 m to 200 m /1,640 ft to 656 ft) (17.0° N, 49.0° W) The Rille starts at about 25km north-west of Marius C, at a width of 2km, winding its way north till it reaches Marius C, where it turns to the west, now only 1km wide. The rille ends about 40km west of Marius P, now only 500m wide. Total length about 250km.

SCHIAPARELLI - Giovanni V. Schiaparelli. (1835 - 1910) Italian astronomer. First one to mention "Channels" on Mars (1877). Invented the system for naming features on Mars still in use today, and named the details he could observe. The names are still in use.

Crater. (24 km /14.9 Mi ø¸ ) (Height: 2,090 m /6,300 ft) (23.4° N, 58.8° W) Circular formation with steep slopes, high walls, a flat floor and a small central mountain. Hills and craterlets.

VALIS SCHRÖTERI - Johann Hieronymus Schröter. (1745 - 1816) Herschel's discovery of Uranus in 1781 inspired Schröter to pursue astronomy. His notes were destroyed by marauding French during the Napoleonic wars.  He worked on the Moon and the planets.

Valley. (Length: 200 km /124 Mi ) (Width: 500 m - 1,000 m /0.31- 6.2Mi) (Depth: 1,000 m /3,000 ft) (26.0° N, 51.0° W) The Schröter Valley, starting 25km north of Herodotus in a 6km wide crater, resembles a winding river, it widens to 10 km and than gradually gets as small as 500m wide, ending at a square shaped non-mare terrain. The valley floor is smooth, and contains a rille, (which is to small to be seen from Earth).

18.