Mercury, Jupiter, and Saturn in the Evening Sky

A few weeks ago Jupiter and Saturn passed very close to each other during the Great Conjunction of 2020. Jupiter and Saturn are now pulling away from each other and are lower in the southwestern sky—but they have been joined by Mercury resulting in a planetary triplet viewable in the twilight.

Mercury, Jupiter, and Saturn in the evening sky.
Mercury, Jupiter, and Saturn in the evening sky.

This is a composite of three images taken over successive nights (09–11 January 2021) that shows the relative motions of the planets Mercury, Jupiter, and Saturn in the southwestern sky. The images have been aligned using Saturn as an anchor point.

Mercury, Jupiter, and Saturn on 09 January 2021.
Mercury, Jupiter, and Saturn on 09 January 2021.

From this composite, one sees small daily motions of Jupiter as it continues to move eastward away from Saturn—which had their Great Conjunction on 21 December 2020. Mercury exhibits large daily eastward motions as it races toward its greatest eastward elongation on 24 January 2021.