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U.A.I. Lunar
Section
Lunar Domes Program |
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2002 observations of lunar domes near Arago and in mare Humorum (abstract) |
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background Image : the region of Marius domes from the Lunar Orbiter ( courtesy NASA)
Lunar domes, from the morphologic
point of view, are low subcircolar reliefs of convex shape, with gentle slopes,
such to give shadows of curvilinear contour. These at renders them different
from the ordinary hilly reliefs, whose shape is generally more irregular. Many
domes are not isolated but are found in groups near the impact basins margins.
J. Westfall in his article "A generic classification of lunar domes",
(J. ALPO, 18, 15-20, 1964 ) gives the following definition, which is adopted
by the UAI lunar section:
"A discrete, regular swelling whose ratio of major axis : minor axis, when
corrected for foreshortening, does not exceed 2:1, and whose maximum slope,
not including secondary features, does not exceed 5°. Under high illumination,
domes are indistinguishable from their surroundings. Domes may exhibit secondary
features, such as pits,clefts, ridges, and hills, as long as any single such
feature does not occupy more than a quarter of the area of the dome. "
Lunar domes are generally similar to Earth shield volcanoes especially when
on the top of the dome a circular craterlet is present, maybe the effusive mouth
of the volcano. In some cases domes can be explained as localized swellings
of the lunar crust, caused by the intrusion to low depth of magma. It must be
noted that the above definition of lunar domes is a morphological one and
not geological. Different origins for lunar domes exist so not all the domes
are volcanic features.
The observation of lunar
domes remains one of the fields where it is still possible to give a useful
contribution to the study of our natural satellite. In fact the high resolution
images taken with lunar probes do not always show this type of morphology clearly,
lunar domes have such a low relief that they can be revealed only when in proximity
of the terminator.
The amateur associations of various Countries therefore have undertaken a study
of lunar domes. The catalogue of domes of the ALPO (Association of Lunar and
Planetary Observers) numbers approximately 600 lunar domes and is in continuous
expansion.
Also the Lunar Section of the U.A.I. proposes a program of observation of domes
based on visual observation, drawings, high resolution photography and CCD images
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The program presents a series of sites where it is possible to observe these
lunar formations easily. Experienced observers will be able to face the search
of new domes, supported by some useful criteria for their classification and
they can contribute to confirm formations of uncertain attribution.
CAUCHY
Omega and Tau
ARAGO
Alfa and Beta
KIES
Pi
N.
HORTENSIUS - MILICHIUS Pi
GRUITHUISEN Gamma e Delta
MARIUS hills
GAMBART C
BEER
CAPUANUS
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NOME
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POSITION
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SELEN.
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NOTES |
IMAGE
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+7.5 / 37,5 |
Omega has a summit crater . Locate to the South of the more southern rima near Cauchy (East edge of M. Tranquillitatis)
FAVOURABLE CONDITIONS OF VISIBILITY drawing and Notes of
R. Porta
Observed domes of Cauchy. Found a series of hills near the south rima.
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+07 / +21 |
elevated
domes with wrinkled surface.
FAVOURABLE CONDITIONS OF VISIBILITY
drawing of: F. Ferri
drawing and Notes of
R. Porta The observation of Arago domes Alpha and Beta is extremely easy, in low light they are visible also with 50x (!). have observed one small rima between the 2 domes that it does not appear on the photos
drawing of: F. Ferri
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-27 / -24 |
Typical dome, summit crater, W of Kies (Nubium sea) FAVORABLE CONDITIONS OF VISIBILITY
drawings and photo of:
A. Catapano PHOTO |
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+7.5 / -28
+10 / - 31,3 |
Group of 5 domes N of Hortensius (W of Copernicus) FAVORABLE CONDITIONS OF VISIBILITY
drawings of: M. Chiarini
Hortensius
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 author: M.Giuntoli 
author: F. Badalotti 
 author: M. Chiarini |
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+ 36 / - 40
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Gamma is a circular flattened dome with summit craterlet; to the South east is Delta of nearly rectangular shape. ( NW margin of Imbrium, to SSW of the Sinus iridum) FAVORABLE CONDITIONS OF VISIBILITY
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 author: A. Cidadao |
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+12 / - 51 |
Field
of 20-30 small domes West of Marius (Oc. Procellarum) |
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+3,3/-11,8 |
Large dome to the
south-west of Gambart c - one of the easiest to recognize visually FAVORABLE CONDITIONS OF VISIBILITY
drawing and notes of: To Catapano Seeing: 3 - 4 Transparency: Good
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 author: A. Catapano |
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+27,1/-9,1 |
Beer is found to the southeast of the Imbrium M. between the craters Timocharis and Archimedes, close to Feuille' (9.5 km). To the South east ofi Beer a dome is found whose dimensions are comparable to the crater (10 km), The dome has a semispherical shape and it seems very low with a tiny shadow , I have not found any summit craterlet, perhaps also because of the seeing being not very good
drawing and notes of:
A. Catapano |
author: A. Catapano |
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-34.0 / - 26,0 |
FAVOURABLE CONDITIONS OF VISIBILITY
drawing of: F. Ferri |
 author: F. Ferri |
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SUSPECTED DOME
NEAR TORRICELLI? From a preliminary analysis the suspected
dome is a lobated relief of Torricelli ejecta, on wich high albedo craterlets
are positioned. All the area is filled with many craters and linear
narrow valleys. In the Clementine and LO images the circular high albedo
area is clearly visible, multispectral data from Clementine indicate
a highland type composition and not a mare terrain. A volcanic classical
dome seems to be excluded. Probably it is an elevated area where highland
terrain is at shallow depth and has been excaved by the craterlets.
It could be a type 6 dome of Head & Gifford lunar mare dome classification. |
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drawings, photos, video and CCD images of lunar domes (please provide date and hour UT, instrumental details) are more than welcome!
Send your observations to:
Fernando Ferri
Via Vasco de Gama, 70
00042 Anzio (Rome) ITALY
Email: luna@uai.it
We will publish your works in
this web page.
