Hertzsprung basin
Large lunar far-side impact basin, ~570 km wide; observed by Artemis II crew during flyby.
Last refreshed: 7 April 2026
What did the Artemis II crew see when they flew over the lunar far side?
Latest on Hertzsprung basin
- What is Hertzsprung basin on the Moon?
- A ~570 km wide multi-ring impact basin on the lunar far side, named after Danish astronomer Ejnar Hertzsprung. Not visible from Earth.
- What did the Artemis crew photograph on the far side of the Moon?
- During a six-hour photography session on 6 April 2026, the crew targeted Hertzsprung basin, Reiner Gamma, Glushko crater, and the Orientale basin.Source: NASA
Background
Hertzsprung basin is a large impact crater basin on the lunar far side, approximately 570 kilometres in diameter. It was among the surface features observed by the Artemis II crew during their six-hour photography programme on 6 April 2026, as Orion passed within 4,070 miles of the Moon. The far side, never visible from Earth, was photographed and observed with unaided human eyes for the first time since Apollo 17 in December 1972.
Named after Danish astronomer Ejnar Hertzsprung, the basin is a multi-ring structure formed by an ancient large impactor. It sits in the northern far-side hemisphere, outside the area visible from Earth even at favourable libration. Its scale places it among the largest confirmed impact basins on the Moon, though smaller than the South Pole-Aitken basin.
The Artemis II flyby is the first time crew members have observed far-side features like Hertzsprung with unaided eyes since Apollo 17. Photographic records from the flyby will be analysed post-mission for geological context relevant to future landing site selection.