Sea / bay

Mare Imbrium

The Sea of Rains is a large lava plain in the northwestern near side. Mountain arcs and prominent craters provide numerous landmarks around its margins.

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Mare Imbrium and surrounding lunar terrain in the LROC Wide Angle Camera mosaic
Mare Imbrium · North up, east right. Open image ↗
NASA / GSFC / Arizona State University · LROC WAC mosaic via USGS. Regional map crop; lighting is fixed and does not follow the selected date.
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Lunar north up, with geocentric libration. Full atlas mode shows the entire facing surface; switch to Selected phase for today’s illumination. Choose a different date in the atlas.

How to observe Mare Imbrium

Begin at low power: find Plato to the north, Archimedes within the plain and the Apennines along the southeastern edge.

Finding the region

Look at 34.72° N, 14.91° W on the lunar disc. The chart marker identifies the catalogue centre. Start with a wide field and use the nearby formations below as landmarks.

Equipment & conditions

These dark plains are a good starting point with binoculars. Trace their shapes at low power, then examine the boundary with the brighter highlands. Higher sunlight helps reveal brightness differences; low sunlight brings out ridges.

Lighting

For surface relief, try a time when the Sun is low over this region. To compare surface brightness and any bright rays, return under higher illumination. The atlas calculates the solar elevation at the formation’s centre for any selected date.

View Mare Imbrium in the atlas

IAU / USGS Gazetteer

Official feature record

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Approved name
Mare Imbrium
Feature classification
Mare, maria
Catalogue dimension / extent
1,145.53 km
Centre latitude
34.72° N
Centre longitude
14.91° W
Name origin (Gazetteer)
"Sea of Showers."

Coordinates are selenographic, with east-positive longitude. Dimensions are the Gazetteer’s catalogue values; for extended formations they do not represent a circular crater diameter. Data snapshot: 2026-09-16. Observing guidance above is separate from the official record.

Nearby formations

The four closest catalogue entries, measured from their centres.

LROC photograph of ArchimedesImpact crater

Archimedes

A broad, dark-floored crater within Mare Imbrium. The relatively smooth interior is a useful contrast to nearby mountain ranges and smaller impact craters.

LROC photograph of Sinus IridumSea / bay

Sinus Iridum

The Bay of Rainbows is a curved embayment on the northwestern edge of Mare Imbrium, bordered by Montes Jura.

LROC photograph of CassiniImpact crater

Cassini

A crater in the northeastern part of Mare Imbrium, close to the Alpine region. Smaller craters inside help distinguish it from nearby formations.

LROC photograph of Montes AlpesMountain range

Montes Alpes

A mountainous region along the northeastern border of Mare Imbrium. Vallis Alpes cuts a distinctive path through this terrain.