Year 2021, Month 12
- 01: A Blue-Banded Blood Moon
- 02: NGC 6822: Barnard's Galaxy
- 03: Comet Leonard and the Whale Galaxy
- 04: Iridescent by Moonlight
- 05: Total Solar Eclipse Below the Bottom of the World
- 06: Space Station Silhouette on the Moon
- 07: Ninety Gravitational Wave Spectrograms and Counting
- 08: Comet Hale-Bopp Over Val Parola Pass
- 09: A Total Eclipse of the Sun
- 10: Eclipse on a Polar Day
- 11: Postcard from the South Pole
- 12: Comet Leonard Before Star Cluster M3
- 13: Meteors and Auroras over Iceland
- 14: HH 666: Carina Dust Pillar with Jet
- 15: Comet Leonard from Space
- 16: Geminids of the South
- 17: Geminid of the North
- 18: Stephan's Quintet
- 19: Planetary Alignment over Italy
- 20: The Comet and the Fireball
- 21: Solstice Sun and Milky Way
- 22: Launch of the IXPE Observatory
- 23: Three Planets and a Comet
- 24: M1: The Crab Nebula
- 25: The Tail of a Christmas Comet
- 26: James Webb Space Telescope over Earth
- 27: Comet Leonard behind JWST Launch Plume
- 28: Sun Halo over Sweden
- 29: Giant Storms and High Clouds on Jupiter
- 30: The Further Tail of Comet Leonard
- 31: JWST on the Road to L2