MOON TOUR
MARE HUMBOLDTIANUM
Great views of the northeastern limb make this elusive lunar sea an intriguing target this month
© NASA
TOP TIP
You should observe this lunar sea when the Moon’s northeastern limb is visible, between 1 and 8 December. A Moon filter will improve contrast.
T his month we turn to the very edge of the Moon and take a look at one of the most elusive lunar seas visible from Earth – Mare Humboldtianum. Located on the Moon’s northeastern limb, Mare Humboldtianum is a dark patch of ancient lava some 270 kilometres (170 miles) across on the lunar nearside. The sea’s eastern edge just touches the 90 degrees east line of longitude.