Helmert (crater)

Helmert
	Apollo 8 Hasselblad camera image
Coordinates	7°34′S87°40′E / 7.56°S 87.67°E
Diameter	26.72 km
Depth	1.0 km
Colongitude	273° at sunrise
Eponym	Friedrich R. Helmert

Last updated December 27, 2023

Helmert is a lunar impact crater at the southern edge of the Mare Smythii. It lies near the eastern limb of the Moon, and from the Earth it is seen nearly from the side. The visibility of this feature can be strongly affected by libration of the Moon in its orbit.

This crater forms part of a merged pair with the similar crater Kao on its northern side. There is a gap in the rims where these two craters are joined, and the interior floors have been resurfaced by lava, leaving a level surface across the bottom of both craters. This floor is nearly featureless, and has the same low albedo as the dark lunar mare to the north. The outer rim has a small crater joined to the eastern edge of the northern gap, but is otherwise not overlain by any notable craters.

Helmert crater is approximately 1000 meters deep based on the high point along its eastern rim and the center of the crater.^[1] The southern crater cuts into highlands which rise more than 2 km above the crater floor.

The crater's name was approved by the IAU in 1973.^[2]

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Lyell is a lunar impact crater that lies along the eastern edge of the Mare Tranquillitatis, at the northern arm of the bay designated Sinus Concordiae. It was named after Scottish geologist Charles Lyell. To the north along the edge of the lunar mare is the crater Franz. The region of terrain to the east of Lyell is named Palus Somni.

Carmichael is a lunar impact crater that is located along the eastern edge of the Sinus Amoris, in the northeastern quadrant of the Moon's near side. Its diameter is 20 km. It was named after American psychologist Leonard Carmichael. It lies within a couple of crater diameters south-southwest of the smaller crater Hill. Further to the east-northeast is the prominent crater Macrobius. Carmichael was designated Macrobius A before being given its current name by the IAU.

Townley is a small lunar impact crater that is located in the eastern part of the Moon. It was named after American astronomer Sidney Dean Townley in 1976. It lies to the northwest of Mare Spumans and southeast of the crater Apollonius. This crater was previously designated Apollonius G.

Haldane is a lunar impact crater that is located in Mare Smythii, near the eastern limb of the Moon. The visibility of this formation is affected by libration, and even under favorable conditions it is highly foreshortened. It lies just to the west-northwest of the crater Runge, and to the east of Carrillo. The small crater Talbot is immediately to the southwest of Haldane.

Gilbert is a large lunar impact crater that lies near the eastern limb of the Moon. Due to its location this feature appears foreshortened when viewed from the Earth, limiting the amount of detail that can be observed. The crater lies to the northwest of the similar-sized walled plain Kästner, to the west of the Mare Smythii.

Fabbroni is a small lunar impact crater that lies along the northern edge of the Mare Tranquillitatis, at the eastern edge of the gap where the lunar mare joins Mare Serenitatis to the north. To the southeast is the crater Vitruvius.

<span class="mw-page-title-main">Daubrée (crater)</span> Crater on the Moon

Daubrée is a lunar impact crater that is located to the southwest of the Mare Serenitatis, just to the west-southwest of the crater Menelaus in the Montes Haemus range. The small lunar mare Lacus Hiemalis lies along the southwest rim of Daubrée. The crater was named after French geologist Gabriel A. Daubrée. It was previously designated Menelaus S.

Kästner is a lunar impact crater that is located near the eastern limb of the Moon, to the southwest of the Mare Smythii. Just to the northwest of Kästner is the walled plain Gilbert. To the south is the prominent crater Ansgarius, and to the southwest lies La Pérouse.

Kiess is a lunar impact crater next to the southern border of the Mare Smythii, near the eastern limb of the Moon. It is located to the east of the crater Kästner, and to the north of Dale and Kreiken.

Widmannstätten is a lunar impact crater in the southern part of the Mare Smythii, near the eastern limb of the Moon. The rim of this crater has a wide gap along the western side, where it is joined to the larger Kiess. There is also a gap in the northern rim where the crater floor is joined to the adjacent lunar mare. The dark interior floor of this formation has been flooded by lava, leaving a level interior surface and a shallow surviving rim.

Van Vleck is a lunar impact crater that is located near the northeastern rim of the walled plain Gilbert, to the west of the Mare Smythii. The similar crater Weierstrass is nearly joined to the northwestern rim of Van Vleck. To the east is the small Carrillo.

Kao is a small lunar impact crater that is located near the eastern limb of the Moon. It lies near the southern edge of the Mare Smythii, a lunar mare that continues onto the far side of the surface. This crater lies to the east-southeast of the crater Widmannstätten. Less than a crater diameter to the north-northeast is the small crater Tucker.

Lebesgue is a small lunar impact crater that is located near the eastern limb of the Moon. It lies in the southeastern part of the Mare Smythii, to the southeast of the crater Warner. The southeastern rim of Lebesgue is attached to a small crater that overlays the northwest rim of Swasey, so that the three form a short crater chain. The floor of Lebesgue is hummocky.

Runge is a lunar impact crater in the Mare Smythii, along the eastern edge of the Moon. It lies less than one crater diameter to the north-northwest of the very similar crater Warner. To the west-northwest is Haldane, and due west is the smaller Talbot.

Swasey is a small lunar impact crater that lies along the eastern limb of the Moon. It lies near the southeastern edge of the Mare Smythii, to the west of the walled plain Hirayama. About one crater diameter to the northeast is Hume, and to the southwest is the merged crater pair of Kao and Helmert.

Talbot is a small lunar impact crater on the Mare Smythii, near the eastern limb of the Moon. It lies between a pair of larger, flooded craters, with Runge to the west and Haldane to the west-northwest. The crater is entirely surrounded by the dark lunar mare. It is a circular, bowl-shaped formation with an almost featureless interior floor. The outer rim has a slightly higher albedo than the surrounding terrain, but the floor is as dark as the mare.

Warner is a lunar impact crater that is located in the southern part of the Mare Smythii, near the eastern limb of the Moon. In this location the crater is viewed almost from the edge from Earth, and is sometimes hidden from sight due to libration. The crater lies just to the south-southeast of the very similar Runge. To the southwest is Widmannstätten, and to the south is the merged Kao–Helmert crater pair.

Hume is a small lunar impact crater that lies along the eastern limb of the Moon, along the southeast edge of Mare Smythii. It is located just on the far side of the Moon, but it is often brought into sight from Earth due to libration. Hume lies just to the west-northwest of the much larger Hirayama, and to the northeast of the flooded crater Swasey.

<span class="mw-page-title-main">Neujmin (crater)</span> Lunar crater

Neujmin is a lunar impact crater on the Moon's far side. It is nearly attached to the west-southwest of the smaller crater Waterman, and lies to the southwest of the prominent Tsiolkovskiy.

References

1 2 LTO-81B3 Widmannstatten, Lunar Topographic Orthophotomap (LTO) Series
↑ Helmert, Gazetteer of Planetary Nomenclature, International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN)

Andersson, L. E.; Whitaker, E. A. (1982). NASA Catalogue of Lunar Nomenclature. NASA RP-1097.
Blue, Jennifer (July 25, 2007). "Gazetteer of Planetary Nomenclature". USGS . Retrieved 2007-08-05.
Bussey, B.; Spudis, P. (2004). The Clementine Atlas of the Moon. New York: Cambridge University Press. ISBN 978-0-521-81528-4.
Cocks, Elijah E.; Cocks, Josiah C. (1995). Who's Who on the Moon: A Biographical Dictionary of Lunar Nomenclature. Tudor Publishers. ISBN 978-0-936389-27-1.
McDowell, Jonathan (July 15, 2007). "Lunar Nomenclature". Jonathan's Space Report . Retrieved 2007-10-24.
Menzel, D. H.; Minnaert, M.; Levin, B.; Dollfus, A.; Bell, B. (1971). "Report on Lunar Nomenclature by the Working Group of Commission 17 of the IAU". Space Science Reviews. 12 (2): 136–186. Bibcode:1971SSRv...12..136M. doi:10.1007/BF00171763. S2CID 122125855.
Moore, Patrick (2001). On the Moon. Sterling Publishing Co. ISBN 978-0-304-35469-6.
Price, Fred W. (1988). The Moon Observer's Handbook. Cambridge University Press. ISBN 978-0-521-33500-3.
Rükl, Antonín (1990). Atlas of the Moon. Kalmbach Books. ISBN 978-0-913135-17-4.
Webb, Rev. T. W. (1962). Celestial Objects for Common Telescopes (6th revised ed.). Dover. ISBN 978-0-486-20917-3.
Whitaker, Ewen A. (1999). Mapping and Naming the Moon. Cambridge University Press. ISBN 978-0-521-62248-6.
Wlasuk, Peter T. (2000). Observing the Moon. Springer. ISBN 978-1-85233-193-1.

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[LTO-81b3-1] 1 2 LTO-81B3 Widmannstatten, Lunar Topographic Orthophotomap (LTO) Series

[2] Helmert, Gazetteer of Planetary Nomenclature, International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN)

[1]

[2]

Apollo 8 Hasselblad camera image
Coordinates	7°34′S87°40′E / 7.56°S 87.67°E / -7.56; 87.67
Diameter	26.72 km
Depth	1.0 km^[1]
Colongitude	273° at sunrise
Eponym	Friedrich R. Helmert