Impact crater

Aristarchus

A bright crater beside the darker Aristarchus plateau in Oceanus Procellarum. Vallis Schroteri winds across the neighbouring plateau.

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Aristarchus and surrounding lunar terrain in the LROC Wide Angle Camera mosaic
Aristarchus · 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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How to observe Aristarchus

Compare the bright crater with nearby Herodotus and the plateau. Look toward Vallis Schroteri for a more challenging target.

Finding the region

Look at 23.73° N, 47.49° 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

Start at low magnification to identify the rim. Move to a moderate power when the air is steady; low sunlight usually makes walls and floor relief easier to distinguish. A bright ray system can be more conspicuous near full Moon.

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 Aristarchus in the atlas

IAU / USGS Gazetteer

Official feature record

View original record ↗
Approved name
Aristarchus
Feature classification
Crater, craters
Catalogue diameter
39.99 km
Centre latitude
23.73° N
Centre longitude
47.49° W
Name origin (Gazetteer)
Greek astronomer (310-230 B.C. ?).

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 Vallis SchroteriValley / rille / scarp

Vallis Schroteri

A winding valley on the Aristarchus plateau. Its shape contrasts with the straight fractures and impact features elsewhere on the Moon.

LROC photograph of Oceanus ProcellarumSea / bay

Oceanus Procellarum

The Ocean of Storms is an extensive dark region across the western near side. Unlike the compact circular maria, it has a broad irregular outline.

2,592.2 kmRead guide ↗
LROC photograph of KeplerImpact crater

Kepler

An isolated ray crater in the western maria, smaller than Copernicus but easy to locate by its bright surroundings.

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.