Hipparchus (lunar crater)

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Hipparchus
Hipparchus (LRO).png
LRO image of Hipparchus
Coordinates5°30′S 4°48′E / 5.5°S 4.8°E / -5.5; 4.8Coordinates: 5°30′S 4°48′E / 5.5°S 4.8°E / -5.5; 4.8
Diameter150 km
Depth3.3 km
Colongitude354° at sunrise
EponymHipparchus

Hipparchus is the degraded remnant of a lunar impact crater. It is located to the southeast of Sinus Medii, near the center of the visible Moon. To the south is the prominent crater Albategnius, and to the southwest lies Ptolemaeus, a feature of comparable dimensions to Hipparchus. Horrocks lies entirely within the northeast rim of the crater. Halley is attached to the south rim, and Hind lies to the southeast. To the north-northeast is the bowl-shaped Pickering, and the flooded Saunder is located off the northeast rim. The features of Hipparchus are highlighted when the Sun is at low angles during the first and last quarter. At full Moon the Sun is directly overhead and the crater contours become more difficult to discern. High-resolution images of Hipparchus were obtained by Lunar Orbiter 5 in 1967.

Description[edit]

Hipparchus seen by Apollo 16

This feature is an ancient crater that has been subject to considerable modification due to subsequent impacts. The western rim of Hipparchus has been all but worn away from impact erosion, and only low hills and rises in the surface remain to outline the feature. The wall to the east is somewhat more intact, but it too is heavily worn. A pair of deep clefts lie in the western wall. These parallel a sets of scars running through the south-central highlands. The crater floor has been partially resurfaced by basaltic lava flow. The southwest part of the floor, however, is slightly raised and much more rugged than the remainder. A few small rises and the raised partial rim of a flooded crater are all that remain of a central massif. Gaps in the northwest rim of Hipparchus form valleys that connect with the mare to the northwest. A rille named Rima Réaumur runs from this site to the outer wall of Réaumur.

Names[edit]

Hipparchus is named after the Greek astronomer, geographer and mathematician Hipparchus. Like many of the craters on the Moon's near side, it was given its name by Giovanni Riccioli, whose 1651 nomenclature system has become standardized.[1] Earlier lunar cartographers had given the feature different names. Johannes Hevelius called it "Olympus Mons", after Mount Olympus of Greece[2] The name Olympus Mons would later be named to the tallest mountain on Mars. The early Hipparchus crater was first named by van Langren as "Hypparchi" in the northernmost of the lunar polar region. One possible location of that crater is where it is now known as Byrd Crater.[3]

Satellite craters[edit]

Hipparchus crater and its satellite craters taken from Earth in 2012 at the University of Hertfordshire's Bayfordbury Observatory with the telescopes Meade LX200 14" and Lumenera Skynyx 2-1
Hipparchus and its surrounding satellite craters in Weinek's Lunar Atlas (1898); North is faced downward

By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Hipparchus. Hipparchus G and W are to the east, Hipparchus L, S and Z are to the southeast, Hipparchus, J, Q, T, U are in the south-southwest, Hipparchus B and K are to the southwest, Hipparchus H and P are to the west and Hipparchus D, E and F are to the northwest. In a Lunar Reconnaissance Orbiter of Hipparchus G taken on June 3, 2014, Beautiful granular flows on the wall of Hipparchus G crater brought fresh debris from the rim down the walls, downslope is to the left. They are dominant in the east of that satellite crater[4]

Hipparchus Latitude Longitude Diameter
B 6.9° S 1.7° E 5 km
C 7.3° S 8.2° E 17 km
D 4.5° S 2.1° E 5 km
E 4.2° S 2.3° E 5 km
F 4.2° S 2.5° E 9 km
G 5.0° S 7.4° E 15 km
H 5.4° S 2.3° E 5 km
J 7.6° S 3.2° E 14 km
K 6.9° S 2.2° E 12 km
L 6.8° S 9.0° E 13 km
N 4.8° S 5.0° E 6 km
P 4.7° S 2.8° E 5 km
Q 8.5° S 2.9° E 8 km
T 7.1° S 3.6° E 8 km
U 6.7° S 3.6° E 8 km
W 5.0° S 7.8° E 5 km
X 5.7° S 4.9° E 17 km
Z 8.5° S 9.1° E 6 km

Hipparchus in fiction[edit]

In the French version of the Tintin book Explorers on the Moon (On a marché sur la lune), the crew lands on Hipparchus.[5]

See also[edit]

Notes[edit]

  1. ^ Ewen A. Whitaker, Mapping and Naming the Moon (Cambridge University Press, 1999), p.61.
  2. ^ Ewen A. Whitaker, Mapping and Naming the Moon (Cambridge University Press, 1999)
  3. ^ Langrenus map of the Moon (1645)
  4. ^ "Tender Tendrils". LROC. June 3, 2014. Retrieved August 21, 2017.
  5. ^ éd. Casterman, coll. Tintin, 1954 (French)

References[edit]

External links[edit]

Related articles[edit]