Penumbral eclipse on Friday, 10 January

There will be a penumbral eclipse of the full Moon on Friday 10 January during the early evening. In this case,  the Moon only goes through the Earth’s outer shadow, the penumbra, rather than through the central part, so will not go completely dark.

The Moon first encounters the dusky shadow at 17:05 GMT, and then gets progressively more covered until 19:10 when it is at maximum eclipse. From then on it starts to move out of the shadow and is completely clear of it by 21:14. The diagram below shows the stages.

Eclipse stages
The penumbral eclipse of 10 January 2020. The arrow shows the Moon’s movement through the shadow, from right to left, although the Moon itself is rising in the sky and moves from lower left to upper right through the evening.

The circles mark the Earth’s shadow, with the central one being the dark area. When the Moon goes through that we get a total eclipse, and the Moon goes deep red and can even disappear from view entirely. But the outer shadow is much paler, so it just appears dimmer than usual, and you will probably notice a gradient of the shadow across it.

The photo below shows what the Moon looked like during an eclipse in 2011 at the same stage in the eclipse as we’ll see at mid eclipse this time. Back then, the Moon went through a different part of the shadow so the dimmest bit is at the top right instead of at the lower right as it will be this time.

Penumbral eclipse
At a penumbral lunar eclipse the Moon isn’t in the deepest part of the Earth’s shadow. Photo: Robin Scagell