Lunar Observing program

Beginning with the April 2017  a Lunar Observing program will be presented at the Regular monthly meeting of the club. The first will be a overview of the moon and the variety of lunar features that can be seen on the Moon with a telescope.

Lunar features visible beginning  2 days after New Moon ,and forward thru the lunar cycle, will be presented throughout the year. Listed here are the descriptions of  craters, Dorsa, Mare, domes, mountains, valleys and rilles in the PowerPoint presentations.

Sources for the features presented

The Moon Observers Guide – Peter Grego
The Moon and How to Observe It – Peter Grego
What’s Hot on the Moon Tonight – Andrew Plank
The Modern Moon – Charles Wood
Lunar Picture of the Day –

Recommended  books, software and websites

Maps and Atlas

Rukl’s Atlas of the Moon – Rukl
Sky & Telescope Field Map of the Moon – Reverse and Nonreverse
The Lunar 100 – Sky & Telescope – Charles Wood

Software maps

Lunar Field Atlas
Virtual Moon Atlas (VMA) free –
Lunar Map Pro commercial –

Photographic Moon Book by Alan Chu –

Photographic Lunar Atlas for Moon Observers by Kwok C. Pau –

Online magazines

ALPO The Lunar Observer –

Following are the lunar features in the PowerPoint presentations by Lunar Day.

Lunar Age Days  2 – 3

Cleomedes (78 miles)

Smooth floor.
2 smaller craters on floor.
Northern wall intrude by 2 craters.
Narrow rile running north of center.
Linear rille running 18 miles branching into two.
Small mountain massif.

Langrenus (82 miles)

Complex crater.
Smooth north floor, rougher in south.
Radial rides spreading northward.
Complex terraced walls.
Two central mountain massif.

Vendelinus (91 miles)

Old eroded crater.
Walls are heavily cratered
Smooth interior.
No central massive

Petavius (110 miles)

Spectacular complex crater.
Smooth north floor, rougher in south.
Straight wide rima, running SW to a deep trench.
Extensive terracing and deep groves.
Central mountain massifs.

Funerius (77.5 miles)

Dark floor in the center surrounded by a floor of sandblasted appearance.
Narrow 43 mile rima, NW to SE.
Extensive terracing and deep groves.
Large crater on floor.
Very small central massif.

Vaillis Rheita (310 miles)

Longest crater chain on the nearside.
Runs from crater Rheita (42 miles)

Lunar Age Days 4 – 5

Atlas (54  miles)

Rims have a very sharp look.
Fracture, rough floor with narrow sinuous rilles.
Radial groves on outer rim and floor.
Cluster of small hills in center.

Hercules (41.5  miles)

Sharp rims with interior terraces.
Smooth floor with large secondary crater in the south.
Very tiny central hill.

Proclus (17.4  miles)

Small bright sharp rim crater.
Very broad bright fan shaped rays that border Palus Somni, a light gray hilly terrain.

Plinus  (62 miles)

Sharp rims and terraced wall.  Large size ejecta brake outside rim.
Two or three central peaks.

Rima Plinus (62 miles)

Set of three linear rills, look like cat scratches.

Dorsa Smirnov ( 200 miles)

Serpentine Ridge.
Braided rope of ridges, some 9 miles wide.

Rima Cauchy (130  miles)
A wide long rille.

Rupes Cauchy (75 miles )

A fault changing to a rille.

Tau and Omega Cauchy

Two domes below Rupes Cauchy.
Look for a central pit in Omega

Messier A (4.3 x 8  miles)
Messier B (8.7 x 5.6  miles)

Two small neighboring craters.
B  is a deep oval  to the E – W
A  is deep circular bowl with a raised lip.
Under high Sun can be see two long linear parallel rays.

Fracastorius (76.8 miles)

A flood crater
Northern wall is obliterated.
Forming a bay on Mare Nectaris.
Small broken rille within.

Posidonis (60 miles  )

Bowl shaped, crater inside west of center.
Very complex floor.
Linear rilles on east floor.
Curving ridge on east wall.

Theophilus (62 miles)

Broad terraced walls.
Impact melt floor.
Group of  4590 ft. peaks form central mound.

Cyrillus (61 miles)

Older eroded neighbor of Theophilus
Disorderly and lower wall.
A ridge along the east wall.
Three long central peaks.

Catharina (61 miles)

Smooth light color floor in the east.
Submerged crater on the south floor.
Mountain ridges with the north floor that connect to Cyrillus.

Rupes Altai (496 miles)

Giant fault cuts a path of 496 miles.
Eastern drop is 74 miles below  the scarp rim.
Runs north of Picolomini.

Picolomini ( 54.6 miles)

Prominent crater.
String internal terraced walls.
Cluster of 6561 mile high central peaks.

Lamont Dorsum 46.5 miles

Inconspicuous feature outlined by wrinkle ridges.

Lunar Age  Days 6 – 7

Aristotles (54 miles)

Very impressive broad terraced wall.
Complex crater with exterior radial ejecta blanket.
Smooth floor with two small covered peaks

Vallis Alpine (120 x 6 miles)

A graben, rift valley, 11 miles at it widest point.
Steep walls up to 6561 ft.
Smooth floor, darker than surrounding mountains.

Eudoxus (41.5 miles)

Terrace walled with complex interior.
Smooth floor in the west.
Grouping of four small central peaks.
Very small sinuous rille in the center.

Aristillus (34 miles) rim 10,824 ft.

Substantial outer radial ejecta blanket.
Collection of central mountain peaks in center.
Complex inner terrain.

Archimedes (50 miles) rim 6232 ft.

Walls display terracing.
Flat flooded floor, light rays deposited on floor.
Central peak is covered by flooded floor.

Autolycus (24 miles) rim 11,250 ft.

Small crater with outer radial ejecta blanket.
Complex floor of extruded lava.
No central peak.

Apennines Mt
.   (370 x 62 miles)

Of the 300 peaks the highest measured peak is over 18,000 ft.

Albategnius (85 miles)

Complex crater with broad inner walls.
Dark, smooth flooded floor.
Central peak, 487 ft., is west of center.
SW wall intruded by 27 mile crater Klien.

Maurolycus (68 miles)

Eastern wall displays terracing.
Western wall rough and disorientated.
NE hilly with small craters.
Central peak, 487 ft., is west of center.
Ragged mountains in North
Broad, deep, curving trench in NW

Ptolemaeus (101 miles) rim 7872 ft.

Circular Plain, Striated walls, Flooded floor.
Six mille crater on floor in NE corner.
No central peak.

Alphonsus (73 miles) rim 8954 ft.

Solitary central peak 9840 ft in height.
Small rilles around edge of floor.
Dark patches around rilles.

Arzachel (59 miles) rim 12.496 ft.

Inner walls have a intricate terracing.
Narrow rima, Rima Arzachel, parallel to east wall.
Central peak, 4900 ft. high, is offset to west from center.

Alpetragius (24.8 miles)

Small prominent crater.
Very large rounded mountain massif that takes up to 1/3 of the crater floor,
that rises up to 2170 feet above crater floor.

Mare Serenitatis

Well defined sea with tonal variations of the albedo
of the different lava flows.

Rima Ariadaeus (136 x 6 miles)

A graben – elongated depression between two parallel faults.
Ground between has fallen away.

Rima Hyginus  (130 miles)

An interlocking chain of craters, or pits, that appear to connect
to crater Hyginus, itself may be a rimless pit.
Each ends are smaller rilles.

Rupes Recta (86 x 16 miles)

(Straight Wall)
A classic fault in  east edge of Mare Nubium.
It is a 7 degree slope, at a height of 800 feet.

Lunar Age  Days 8 – 9

Plato (68.2 miles)

Very prominent Dark floor crater.
The floor is 6561 feet below rim.
Shadows cast by rim onto the floor is a spectacular sight.

Timocharis (21 miles)

A remarkable small crater.
Substantial sharp terraced wall.
Without a central mountain peak.
Has a 3.7 mile crater in middle of floor.

Eratosthenes (36 miles)

Complex crater with sharp rim and wide internal terraced walls.
Floor shows impact sculpting  surrounding the 3 mountain peaks.
Outside is a thick ejecta blanket.

Copernicus (57.7 miles)

Young crater with impressive radial ray.
Secondary impacts from excavation of crater.
Complicated terraced walls and internal landslides.
Floor is 12,464 feet below rim.
Two major mountain massive peaks.

Reinhold (30 miles)

Smooth floor containing small hills instead of a mountain massif peaks.
Strongly terraced walls.

Bullialdus (37.8 miles)

Very prominent crater with an indent on the SE wall.
Intricate terraced walls.
Tight group of central peaks

Pitatus (60 miles)

Eroded crater with complex rills system on flat floor.
Low terraced walls.

Tycho (52.7 miles)

Has the largest and complex system of rays.
Impressive sharp rim terraced walls.
Interior floor filled pool of impact melt.
Large pair of mountain massif peaks.
Dark collar of impact melt outside of the rim.

Clavius (140 miles)

Large flat floor crater with a scalloped rim.
Heavily cratered floor with a distinct small arc of unconnected craters.


Milichius dome – an isolated  3 mile diameter dome with a central pit.

Hortensius domes – Six dome cluster field, 1 to 3 miles in size, with central pits.

Lunar Age  Day  10 – 11

Sinus Iridum (160 miles)

Very prominent Dark floor crater.
Southern half of the rim is overrun by lava flow of Mare Imbrium.
The floor is 6561 feet below rim.
Shadows cast by rim onto the floor is a spectacular sight.

Mons Gruithuisen

Second largest dome with a small summit crater.

Mon Rumker (43 miles)

Broad lumpy plateau.
Largest dome complex.

(24 miles)

Brightest ray crater on the moon.
Western wall show radial banding of alternating
dark and bright features.

Vallis Schroteri (3 x 6 wide  x 100 long miles)

Impressive sinuous rille, a collapse 3000 ft deep lava tube.
It starts at the “Cobra Head” rim and runs 100 miles to Oceanus Procellarum
Exterior mound shows radial structure.

Reiner Gamma (37  x 90 miles)

Young crater with impressive radial ray.
Secondary impacts from excavation of crater.
Complicated terraced walls and internal landslides.
Floor is 12,464 feet below rim.
Two major mountain massive peaks

Kepler (20 miles)

Terraced walled crater with small hills
instead of central mountain peak.
Sun aged rays span a good distance,
interacting with rays of Copernicus.

Gassendi (68 miles)

Magnificent crater on the North boundary of Mare Humorum.
Complex floor containing small hills, mountains, ridges and rilles.
Has three of a mountain peaks.
Walls are partial submerged by Mare Humorum.

Schiller (111 x 42 miles)

Elongated flood crater.
Southern is very smooth, north has an prominent central mountain Ridge.
May have been formed by 3 or 4 impacts.

Schickard (140 miles)

Low circular walls with around a smooth floor.
Darker floor in the north, brighter floor in the south
that a darker patch near the wall rim.

Wargentin (52 miles)

Strange sight of a crater filled up to the top of it’s
rim with extruded lava. Y shaped ridge on center.

Lunar Age  Days 12 – 15

Pythagoras (80 miles)

Broad scalloped rim walls.
Hilly interior floor,
with a central mountain peak.

Seleucus (27 miles)

Sharp rim crater with broad inner terraced walls.
Dark inner floor with a small central hill.
Has exterior ejecta blanket.
Bright broad rim and dark interior floor under high sunlight.

Struve (105 miles)

Large elongated flood crater with sharp rims.
North wall  all is eroded by lave flow.

Russell (64 miles)

Shares a eroded wall with crater Struve.
Flooded floore is smooth, does not have a central peak.

Cavalerius (36 miles)

Deep crater with a sharp rim with signs of terraced walls.
Small central hill.

Hevelius (66 miles)

Eroded wall crater with rilles on the interior floor.
Rima Helevlius rille crisscross to form an X pattern
with smmaler sinious rille before it continues outside
of the crater wall.

Grimaldi (27 miles)

Broad dark lava plain.
Broken hills surround the plain.
Very prominent

Riccioli (90.5 miles)

Well defined low wall crater.
Complex interior floor,small rilles and hilly in the south.
Large dark patch in the north.

Bailly (189 miles)

Largest crater on the Moon best seen during favorable librations.
Low multi ring impact basin.
Eroded outer walls, rough crater floor.

South Polar Region

Numerous mountains around lunar rim near the pole.

Mare Orientale (580 miles)

Very large Multi Ring Impact Basin.

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