Montes Secchi

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Montes Secchi and Mount Marilyn (Secchi Theta)

Lat: 3.0°N, Long: 43.0°E, Diam: 50 km, Height: km, Rükl: 37

external image normal_Secchi-Peaks_CLA-D6_LTVT.JPG
Consolidated Lunar Atlas This image has been annotated to show the classic Greek-lettered satellite features of Secchi in the original IAU system of Blagg and Müller as identified by the Army Map Service (the Greek-lettered nomenclature for lunar peaks was discontinued by the IAU in [[IAU Transactions XVB}1973]]. The unlabeled peak between Theta and Iota was possibly Lubbock Gamma (whose coordinates are given as 1 degree west of Iota; but the Army Map Service identifies that with the extension farther to the south. There is also a rille (Lubbock I) listed at the same position (41°W/0°N), but its intended identity is unclear. The System of Lunar Craters appears to have deleted all the Greek-lettered peaks except Theta, but added the 6-km lettered crater Secchi U (the bright central crater between Eta and Chi) as well as adding Secchi G, K and X (K and X straddle Rima Messier in the mare on the right; G is very hard to see, a bit above the “Secchi” label and hidden in shadow). It also named the vaguely defined 24-km diameter “craters” to the southwest and northeast of the Lubbock Gamma(??) peak as Lubbock R and Lubbock S, respectively. The prominent crater at the tip of the Secchi Iota peninsula seems to have gone unnoticed. A matching Lunar Orbiter view, showing this region with a higher Sun from the opposite side, is also available.


LPOD Photo Gallery Lunar Orbiter Images Apollo Images
- The first photograph in Apollo 8's series of the Landmark Tracking Exercise shows part of Montes Secchi near the frame's left margin. See: AS8-13-2271. South toward the top.
- Lunar Orbiter 1's Frame 1041, on which some of the Montes Secchi are visible (with the so-called Mount Marilyn in it, aka Secchi Theta).
- Orbital Hasselblad photograph AS10-35-5209 shows most of the Montes Secchi and adjacent Secchi Theta (the triangular peninsula which was called Mount Marilyn by James Lovell of Apollo 8 and Apollo 13, see Nomenclature below).
- AS10-28-4165 is one of Apollo 10's orbital B-and-W Hasselblad photographs which show both CSM Charlie Brown and Mount Marilyn in the distance.
- AS10-30-4437 is an oblique look at Mount Marilyn.
Research Lunar Orbiter and Apollo photographs: Danny Caes


(LAC zone 61C4) LAC map Geologic map AIC map LTO map


Description: Elger

(IAU Directions) MONTES SECCHI.--South of Secchi there is a lofty prominent isolated mountain.

  • The peak mentioned by Elger is probably the classic Secchi Chi, which Neison also calls attention to but misprints (as Blagg notes in her Collated List) as Secchi Psi in his text. There is nothing to indicate this is actually the tallest peak in the area. Indeed, the LTO suggests it is not.- JimMosher

Description: Wikipedia

Montes Secchi

Additional Information


  • Named after the nearby crater. (Secchi)
  • Although Elger mentions a peak in this area, the name Montes Secchi was not part of the original IAU nomenclature or of the System of Lunar Craters (although there were several named Greek-letter elevations, as explained in detail in the figure caption above). After the classic Greek-lettered peak designations were discontinued by the IAU in 1973, the name Montes Secchi was provisionally introduced on LTO-61C4, on which it referred to the group of hills to the southwest of Secchi. The name was approved by the IAU in 1976 with no specific indication of what it referred to IAU Transactions XVIB. The position and “diameter” listed in the on-line IAU Planetary Gazetteer corresponds roughly to the small ridge visible in CLA Plate D6 tangent to Secchi on the northwest; and does not include any of the classic Greek-lettered peaks. This is inconsistent with LTO 61C4 where the name Montes Secchi is printed considerably farther to the south. It starts over the elevation step to the northeast of the classic Secchi Eta peak, and runs eastward to the southern edge of Secchi. Unfortunately, the indication of what names are meant to apply to on LTO charts is rarely clear. In this particular case it is impossible to tell which peaks were meant to be included. According to the LTO contours, the Secchi Theta peak is the tallest, with the unlabled peak between Theta and Iota a close runner-up. The peak immediately outside Secchi’s west rim, and the ridge extending to the northeast (which did not have names in the classic system, but seem to be the IAU’s Montes Secchi) are also about the same height as this latter peak. In the photographs, these peaks are not as impressive, but this is, at least in part, because they attain their elevation over a longer distance, giving them gentler slopes which have less tendency to cast shadows.

  • In summary, until a clear IAU map is produced, what was once a reasonably well defined set of individually named peaks has been replaced with a vaguely defined “mountain range” which probably does not include the formerly-named peaks.
  • - JimMosher

Mount Marilyn

  • The pronounced peak Secchi Theta (1°30' North/ 40° East) which looks like some sort of triangular peninsula, was called Mount Marilyn (after his wife) by Apollo 8 astronaut James Lovell. One of the orbital Hasselblad photographs which was made by the orbiting crew of Apollo 10 (AS10-31-4521) shows Secchi Theta (Mount Marilyn) in close-up. To learn more about NASA's unofficial nomenclature at the Montes Secchi/ Maskelyne region, please visit Phil Stooke's LPOD US-1 and Other Signposts from September 10, 2007. Research: Danny Caes
  • AS11-37-5446, made through one of LM Eagle's small windows, shows CSM Columbia over Cape Venus and The Cape (both west-southwest of Mount Marilyn). Research: Danny Caes

LPOD Articles

Seeking Secchi

LROC Articles

Mount Marilyn: Navigating to the Surface