Impact crater

Gassendi

A large crater on the northern edge of Mare Humorum. Its floor contains central peaks and a network of fractures.

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Gassendi and surrounding lunar terrain in the LROC Wide Angle Camera mosaic
Gassendi · 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 Gassendi

Locate the smaller crater interrupting the northern rim, then inspect the central peaks. Fine floor fractures are a challenging follow-up.

Finding the region

Look at 17.55° S, 39.96° 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 Gassendi in the atlas

IAU / USGS Gazetteer

Official feature record

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Approved name
Gassendi
Feature classification
Crater, craters
Catalogue diameter
111.39 km
Centre latitude
17.55° S
Centre longitude
39.96° W
Name origin (Gazetteer)
Pierre; French astronomer, mathematician (1592-1655).

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 Mare HumorumSea / bay

Mare Humorum

The Sea of Moisture is a rounded dark plain in the southwestern near side. Gassendi marks its northern edge.

LROC photograph of Mare NubiumSea / bay

Mare Nubium

The Sea of Clouds is an irregular dark region south of the lunar equator. Partly buried formations and neighbouring highlands make its borders varied.

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 SchickardImpact crater

Schickard

A broad walled plain in the southwestern lunar highlands. Different parts of its floor have noticeably different surface brightness.