How to observe Mare Humorum
Trace the boundary between dark plain and bright highlands, then inspect Gassendi when its rim is near the terminator.
Finding the region
Look at 24.48° S, 38.57° 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 Humorum in the atlas →



