Atlas

Atlas, with Rimae Atlas on its floor

Lat: 46.7°N, Long: 44.4°E, Diam: 87 km, Depth: 2.05 km, Rükl: 15, Upper Imbrian

Orbital close-up photograph of Atlas made by the temporary lunar orbiter Clementine (1994).
Atlas is one of several pronounced craters on the moon's near and far sides which show curious cobweb-shaped systems of rilles on their floor.
The rilles on the floor of Atlas have been known as Rimae Atlas I, II, III, IV, and V.

Images

LPOD Photo Gallery Lunar Orbiter Images Apollo Images

Maps

(LAC zone 27A2) LAC map Geologic map

Description

Description: Elger

(IAU Directions) ATLAS.--This, and its companion Hercules on the W., form under oblique illumination a very beautiful pair, scarcely surpassed by any other similar objects on the first quadrant. Its lofty rampart, 55 miles in diameter, is surmounted by peaks, which on the N. tower to an altitude of nearly 11,000 feet. It exhibits an approach to a polygonal outline, the lineal character of the border being especially well marked on the N. The detail on the somewhat dark interior will repay careful scrutiny with high powers. There is a small but distinct central mountain, south of which stands a number of smaller hills, forming with the first a circular arrangement, suggestive of the idea that they represent the relics of a large central crater. Several clefts may be seen on the floor under suitable illumination, among them a forked cleft on the N.W. quarter, and two others, originating at a dusky pit of irregular form situated near the foot of the S.W. wall, one of which runs E. of the central hills, and the other on the opposite side. A ridge, at times resembling a light marking, extends from the central mountain to the N. border. During the years 1870 and 1871 I bestowed some attention on the dusky pit, and was led to suspect that both it and the surrounding area vary considerably in tone from time to time. Professor W.H. Pickering, observing the formation in 1891 with a 13 inch telescope under the favourable atmospheric conditions which prevail at Arequipa, Peru, confirmed this supposition, and has discovered some very interesting and suggestive facts relating to these variations, which, it is hoped, will soon be made public. On the plain a short distance beyond the foot of the glacis of the S.W. wall, I have frequently noted a second dusky spot, from which proceeds, towards the W., a long rill-like marking. On the N. there is a large formation enclosed by rectilineal ridges. The outer slopes of the rampart of Atlas are very noteworthy under a low sun.

Description: Wikipedia

Atlas

Additional Information

• Depth data from Kurt Fisher database
  • Westfall, 2000: 2.05 km
  • Viscardy, 1985: 3 km
  • Cherrington, 1969: 3.04 km
• Central peak height
  • Sekiguchi, 1972: 0.9 km "The most distinct, cone-formed peak, standing on the westerly eccentric position"
    • "Low mound, which may be the true central peak": 0.6 km
    • "Tiny mound on the south of [the cone-formed peak]": 0.2 km
    • "Three mounds standing in a line": 0.2 km, 0.5 km, 0.2 km - fatastronomer fatastronomer
• Contains dark halo craters and thus pyroclastic deposits. * Two small pyroclastic deposit (areas = 100 & 250 km^2) on N and S sides of crater floor. Gaddis, L. (1999) Lunar Pyroclastic Volcanism Project.
• Depth is from the less accurate LAC 27.
• Central peak composition: GNTA1 & AG (Tompkins & Pieters, 1999)
• Satellite crater Atlas A is on the ALPO list of banded craters
• Atlas E central peak height:
  • Sekiguchi, 1972: 0.7 km - fatastronomer fatastronomer
• Walter Goodacre observed, near local sunset, "a light brown shade extending from the crest of Atlas' wall halfway across the floor" (T.W. Webb's Celestial Objects for Common Telescopes, Volume 1: The Solar System, page 160).
• TSI = 20, CPI = 25, FI = 25; MI =70 Smith and Sanchez, 1973
• More than 98% anorthosite in central peak, and 0.2 to 0.6 Maturity Index (not mature) Ohtake and others, 2009
• During local sunset circumstances (evening terminator), the last stages of illumination show a wonderful "broken semi-circle effect" at the eastern part of Atlas's rim (a noteworthy clair-obscur effect!). See LPOD From Sea to Shining Sea.

Nomenclature

• According to the IAU Planetary Gazetteer, named for Atlas, one of the primordial Titans in Greek mythology, where a Titan and a Titaness are assigned each of the seven planetary powers. Atlas is paired with Phoebe and governs the moon.
• The name was given by Riccioli. As astronomical historian Robert Garfinkle has pointed out, Riccioli drew the name from a list in which the full name is given as Atlas Rex Mauritaniae, a mythical "King of Mauritana", who Riccioli thought lived around 1580 B.C. (Riccioli says he found reference to him in Pliny, Book 5(?), Chapter 8 and in Diodorus Siculus, Book 4), a figure possibly distinct from the Greek Titan, but also closely entwined with those legends since Riccioli regarded him as the brother of Prometheus (circa 1590 B.C.) and the grandfather of Mercurius (circa 1510 B.C.). The same Atlas Rex Mauritaniae (distinct from the Titan) is reportedly the inspiration for the word "Atlas" for a collection of maps, first used by Mercator whose original Atlas was dedicated to this personage.
• Whatever its significance, the name has continued in use, unchanged. This feature is Catalog Entry 437 in the Collated List and in Named Lunar Formations.
• Michel Florent Van Langren (Langrenus) called it (Riccioli's Atlas) Blitterswyckii, see page 195 of Ewen A. Whitaker's Mapping and Naming the Moon.
• Atlas E was called O'Kell by Wilkins and Moore, but the IAU did not accept that name. O'Kell was an English amateur astronomer (1861-1947). Could have been a certain Samuel O'Kell (?).
• The bright ray crater east of Atlas is not officially named, however, it is unofficially nicknamed Atlas Companion by B.Dembowski.
• Atlas P, an irregular "crater" east-northeast of Atlas itself (northwest of Lacus Temporis) has a pronounced hill on the eastern part of its rim. According to SLC map B1, that hill received the Greek letter designation Epsilon (Atlas Epsilon?). See SLC-B1 (System of Lunar Craters, 1966).

LPOD Articles

Hiding a Mouse. Atlas Alone A Tale of Two Craters Lunar Super-Heroes A Wonderful Corner Ejecta Tales (a wonderful look at the bright raycrater east of Atlas)

Lunar 100

L72: Explosive volcanic pits on the floor of Atlas.

Bibliography

• Hawke, BR, CR Coombs, LR Gaddis, PG Lucey & PD Owensby (1989) Remote sensing and geologic studies of localized dark mantle deposits on the Moon. Proc. 19th Lunar Planet. Sci. Conf., 255-268.
• Gaddis, L.R. and others (2012) Volcanism within Floor-fractured Atlas Crater 43rd LPSC #2728.

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