December 3rd: The nearly full Moon will once again pass through the Pleiades star cluster. For the naked eye, the bright moon will make it hard to see the faint stars of the cluster, but binocular or small telescope viewing will show multiple stars disappearing and reappearing around the Moon's limb.

 

December 6th: The swift planet Mercury returns to the morning skies and reaches its highest altitude shortly before sunrise on the eastern horizon.

 

December 13-14th: One of the best meteor showers of the year peaks this evening - the Geminids. Dark skies can produce meteors rates of over 100 per hour, with best viewing from about 10pm to 3am, before moonrise. While the meteors will appear to originate from the constellation Gemini, they can be seen streaking over the entire sky.

 

December 21st: The winter solstice for the northern hemisphere occurs at 10:04 am EST, marking the shortest day of the year for northerly latitudes. 

 

December 26: A holiday treat, the waxing crescent Moon will meet up with Saturn in the sky, visible from after sunset until around 11:30pm when the pair set. 

 

December 7th: The anniversary of the launch of Apollo 17 in 1972, the last crewed expedition to the Moon and also the mission that provided the iconic "Blue Marble" image of the Earth from space.

 

December 14th: Mariner 2 became the first successful interplanetary mission on this date in 1962 during a flyby of the planet Venus. 

 

December 19th: Gaia launched on this date in 2013 and operated through March of 2025, providing distance and motion measurements of about a billion targets.

 

NET December: Planned return of Soyuz MS-27 capsule from the International Space Station, returning two cosmonauts and an astronaut to Earth.

 

NET December 20th: Test flight of the new Russian Soyuz-5 rocket is planned for launch before the end of the year.

December 4th - Full Supermoon (Cold Moon)

December 11th - 3rd Quarter

December 19th - New

December 27th - 1st Quarter

 

Mercury - Best visibility early in the month before sunrise, low on the eastern horizon. Sinking into the Sun's glare by the end of the month.

 

Venus - Also best visible early in the month just before sunrise, but getting too close to the Sun by the end of the month.

 

Mars - Too close to the Sun throughout the month for easy viewing.

 

Jupiter - Rising in the east around 8:30pm at the beginning of the month, 6:30pm by the end of the month, and visible throughout the evening.

 

Saturn - Setting around 1am at the beginning of the month, 11pm at the end of the month, best visible shortly after sunset.