December brings cold winter nights and some of the clearest skies of the year for many locations. Bundle up to keep warm and get outside for some holiday stargazing fun!
Geminids Meteors. Grab a blanket and get outside after nightfall on December 13th-14th to see meteors streak across the sky during the peak of the Geminids shower. The Geminids normally produces up to 100 meteors per hour at its peak, so it's worth braving the cold to catch this impressive celestial lightshow. This year, the Full Moon coincides with the peak of the Geminids, so only the brightest meteors will be visible. Look for meteors to radiate out from the general area of the constellation Gemini. All you need to enjoy the show is a lounge chair, a warm blanket, and your eyes!
Third "Supermoon" of 2016. Even though the Full Moon on December 13th will make it harder to see Geminids meteors, it's a noteworthy spectacle on its own since it will be the third and last so-called "Supermoon" of 2016. The perigee Full Moon will be at its closest approach to Earth and will appear about 7% larger than average and approximately 16% brighter. The best time to catch the third and last Supermoon of 2016 will be just after moonrise, which this month will be in late afternoon.
Orion High in the Sky. Our namesake constellation will be well-placed for backyard astronomers throughout December. Some of our favorite targets in or near Orion are:
- M42, The Great Nebula in Orion — Visible as the middle star of Orion's sword, this emission nebula looks amazing in everything from binoculars to the XX16g! Can you see the Trapezium Cluster, the 4-star system at the center of M42?
- M78 — Another, much fainter, emission nebula, M78, is located just left and above the left-most star in Orion's belt.
- NGC 2174/2175 — A large emission patch — known as the Monkey Head nebula — and star cluster, this interesting complex is located near the top of Orion's raised "hand". Try to spot NGC 2174/2175 under dark and clear skies using larger binoculars or a wide-field telescope.
Best Binocular Targets. While 50mm binoculars are good for December stargazing, bigger 70mm, 80mm, or larger binos will reveal brighter and better views of celestial gems, of which there are plenty to enjoy in December skies. The glorious open star cluster M45, also known as the Pleiades, will be nearly overhead in the constellation Perseus. A little more north and overhead you'll find the Andromeda Galaxy (M31), which really shines in big binoculars. Slightly to the northwest of M31 you'll see the beautiful Double Cluster of Perseus.
Best Telescope Targets. All of the binocular targets listed above also make great telescope quarry, but December skies offer great opportunities to see objects that require a telescope too. First, slew your scope just a few degrees southwest of M31 to find M33, a distant face-on spiral galaxy that's about 2.5 million light years (MLY) away from Earth. In the constellation Sculptor far to the south, try to find NGC 253, the impressive "silver dollar" galaxy. There's a swarm of other galaxies to see in the general area of NGC 253 — all part of the "Sculptor Group" of galaxies. Use a star chart or the Orion StarSeek app and hunt them down! In Pisces, look for M74, another face-on spiral galaxy like M33, but one that is almost 30 MLY farther away from us. Finally, check out NGC 1300, a classic barred spiral galaxy that is approximately 61 MLY away from Earth with a monster black-hole in its nucleus.
December Challenge. With a 10" or larger telescope from a dark sky site, try to track down the dark and picturesque Horsehead Nebula near the eastern star of Orion's belt, which is named Alnitak.
M45 by Timothy Martin
All objects described above can easily be seen with the suggested equipment from a dark sky site, a viewing location some distance away from city lights where light pollution and when bright moonlight does not overpower the stars.