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Lat: 43.31°S, Long: 11.36°W, Diam: 86.21 km, Depth: 4.7 km, Rükl: 64, Copernican

external image normal_Tycho_LO-V-125M_LTVT.JPG

external image normal_tycho_1_18_06.jpg

Left: LO-V-125M As viewed from orbit.
Right: Steve Bryson As viewed from Earth with similar lighting.


LPOD Photo Gallery Lunar Orbiter Images Apollo Images WARNING: none of the seven Apollo 10 photographs in the LPI's list show Tycho! All of them were made at the eastern part of the moon's far side.- DannyCaes Nov 14, 2012

  • A very impressive orbital photograph of Tycho's chaotic floor and central peak, made by Lunar Orbiter 5 (Frame 5125 medium), was included on pages 234-235 in the National Geographic of February 1969 ("Awesome Views of the Forbidding Moonscape"; a nine-page portfolio). The chaotic nature of the floor is most apparent in the high-resolution segments, which cover a swath just north of the central peaks. Research Danny Caes.
  • Kaguya images (the following frames seem to be taken from a simulated Tycho flyby which can also be downloaded as a 286 MB zip file in *.mpg format):
    • central peaks - viewed obliquely from the south
    • central peaks - closer image from the south
    • central peaks - more distant view from the southwest
    • south rim - oblique view of inner wall from point to east of centerline, looking west
    • west rim - oblique view of inner wall looking north


(LAC zone 112D1) USGS Digital Atlas PDF LAC map Geologic map LRO LOLA Topo Map (See 3.26.2010)



(IAU Directions) TYCHO.--As the centre from which the principal bright ray-system of the moon radiates, and the most conspicuous object in the southern hemisphere, this noble ring-plain may justly claim the pre-eminent title of "the Metropolitan crater." It is more than 54 miles in diameter, and its massive border, everywhere traversed by terraces and variegated by depressions within and without, is surmounted by peaks rising both on the W. and E. to a height of about 17,000 feet above the bright interior, on which stands a magnificent central mountain at least 5,000 feet in altitude. Were it not somewhat foreshortened, Tycho would be seen to deviate considerably from what is deemed to be the normal shape. On the S. and E. especially, the wall approximates to the linear type, no signs of curvature being apparent where these sections meet. The crest on the S. and S.W. exhibits many breaks and irregularities; and it is through a narrow gap on the S. that a rill-like valley, originating at a small depression near the foot of the S.E. glacis, passes, and, descending the inner slope of the S.W. wall obliquely, terminates near its foot. There is a distinct crater on the summit ridge on the S.W., and another below the crest on the outer S.E. slope. On the S. inner slope I have often remarked a number of bright oval objects, which, for the lack of a better word, may be termed "mounds" though they represent masses of material many miles in length and breadth. The outer slope of Tycho, exhibiting under a high light a grey nimbus encircling the wall, includes--craters, crater-pits, shallow valleys, spurs and buttresses--in short, almost every variety of lunar feature is represented. Excepting the central mountain and a crater on the E. of it, I have not seen any object on the floor, which, for some unexplained reason, is never very distinct. Schmidt shows several low ridges on the N.W. side. In a paper recently published in the Astronomische Nachrichten, Professor W.H. Pickering, describing his observations of the Tycho streaks made at Arequipa, Peru, with a 13 inch achromatic, asserts that they do not radiate from the centre of Tycho, but from a multitude of minute craters on its S.W. or N. rim. (See Introduction.)



Additional Information

  • IAU page: Tycho
  • Depth data from Kurt Fisher database
    • Margot, 1999: 4.7 km
    • Pike, 1976: 4.6 km
    • Westfall, 2000: 4.6 km
    • Viscardy, 1985: 4.8 km
    • Cherrington, 1969: 4.2 km
  • The topography of Tycho was studied in considerable detail by Margot et al. (1999) based on radar interferometric measurements. They found a mean rim to floor difference of 4.7 km, and a central peak height of 2.4 km. The western floor was found to be 200 m higher than the eastern floor, with their average being approximately 1734.03 km from the Moon's center.
  • Tycho's diameter is listed as 102 km in the IAU Planetary Gazetteer, however the correct diameter of the rimcrest, as given in the Margot et al. article and by measurement on Lunar Orbiter photos is 85 km. - JimMosher
  • West rim slope 34°, east rim slope 46° (Pohn, 1963)
  • Radar bright at 70 cm.
  • Possible oblique impact – downrange E - based upon dark collar (impact melt) most evident to N, width 0.8 crater diameter. [Kirata et al LPSC 30: 1350]. This suggestion is supported by Tycho's rays which are not equally distributed in all directions.
  • Central peak composition: GNTA2, AG, AGN, G. Tycho is the most mafic peak observed. Its walls are also mafic, and since wall represent shallow rocks and the peaks, deeper ones, it has been suggested that Tycho formed on a pluton (igneous rock that rose through the crust as a pod) that must be at least Tycho's diameter wide and 15-20 km deep. Nearby craters are not mafic so Tycho is on an isolated piece of unusual rock. (Tompkins & Pieters, 1999)
  • Exterior impact melt deposits most extensive to E, max of ~35 km beyond rim. Most extensive ejecta, rays and secondary craters to the E, with max wall slumping on SW side of crater, and topographically lowest rim crest to E (Hawke and Head, 1977).
  • Included in ALPO list of bright ray craters
  • TSI = 35, CPI = 20, FI = 20; MI =65 Smith and Sanchez, 1973
  • A compact cluster of 150/ 200 meter sized boulders could be detected at Longitude -12.9, Latitude -43.27 (Res: 4 m/pix) on the western inner slopes of Tycho. The most southern example of this cluster has a diameter of more than 200 meter. See the LRO's ACT-REACT Quick Map. Research Danny Caes.


  • Named for Tycho Brahe (December 14, 1546 – October 24, 1601), a Danish nobleman, best known today as an early astronomer. He is credited with the most accurate astronomical observations of his time, and the data were used by his assistant Kepler to derive the laws of planetary motion. No one before Tycho had attempted to make so many redundant observations, and the mathematical tools to take advantage of them had not yet been developed. He did what others before him were unable or unwilling to do — to catalogue the planets and stars with enough accuracy so as to determine whether the Ptolemaic or Copernican system was more valid in describing the heavens.
  • According to Whitaker (p. 33), the earliest name for Tycho may have been Umbilicus Lunaris ("navel of the Moon"), suggested by Gassendi in the 1630's in connection with a never-completed lunar mapping scheme. Van Langren introduced the name Brahei, however he used it for the crater now known as Aristoteles (p. 195). On his manuscript map, the modern Tycho was (according to Whitaker) labeled Annae (a name Van Langren later transferred to Arzachel), and Tycho was labeled Vladislai IV Reg. Pol. (pp. 191, 197, and 198). Hevelius used the name Mons Sinai for Tycho (p. 207) and Desertum Zin for the "north half of dark halo around Tycho" (p. 208).
  • The modern usage of Tycho appears to have been introduced by Riccioli. Whitaker does not mention this, since he doesn't regard it as "new" name, Brahei having been earlier honored by Van Langren. - JimMosher Jul 17, 2008
  • Tycho was part of the original IAU nomenclature of Blagg and Müller (1935).
  • A possible Catena (a crater chain) is located near craters Tycho U and Heinsius Q (north-northwest of Tycho itself). It (Catena Tycho) could be the "source" of the western one of the bright double ray toward Weiss. Detected by Danny Caes on LPOD Abrasion and Rhino Hide.
  • J. H. Schroter's Rob. Smith (plate T. LV). A very well defined 72 km crater to the southwest of Tycho, extending from the modern Tycho D to Brown D and centered at 15.2°W, 45.4°S. It is drawn, but not named, in the System of Lunar Craters. The reference is presumably to Robert Smith (1689-1768), author of a famous book on Optics (1738). Research Jim Mosher.

LROC Articles

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Lunar 100

L6: Large rayed crater with impact melts


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