I haven’t done one of these for a while.

This is Phobos: one of Mars’s two moons, from Astronomy Picture of the Day, 28/10/12. Phobos definitely resembles a potato in this view. Its orbit is so close to Mars that it will eventually be broken up by tidal forces and the remnants smeared into a ring around the planet.

Another image from Astronomy Picture of the Day.

Sunday’s picture, this is a composite photo of Mars showing the great rift valley named Valles Marineris which almost bisects the hemisphere shown.

3,000 kilometres long, 600 across and up to 8 deep, Valles Marineris could swallow the Grand Canyon many times over.

Mind-boggling.