What's Up: The Sky Tonight


Each month on this page, the Big Sky Astronomy club hosts a video, produce by the Space Telescope Science Institute (STScI) featuring the planets, deep sky objects and one or more of the constellations that are visible in our night sky at this particular time of year.


Tonight's Sky, during the month of December, 2018:

  • The early nighttime hours during the first part of December 2018 have the planets Mars and Saturn low in the southernwestern sky after dusk.

  • Saturn is slowly creeping towards the western horizon, soon to be lost in the Sun's glare;

  • Mars, the "God of War" has moved into the constellation Sagittarius and is decreasing in size and dimming as the Earth moves away from it in our quicker orbit. A small telescope will display its reddish disk;

  • Two new seasonal constellations appear this month, both representing notable figures in Greek Mythology;

  • The great Greecian hero Perseus holds the severed head of the terrifying Gorgon, Medusa, in his left hand and an uplifted sword in his right;

  • A beutiful open star cluster, M34, resides in Perseus. Under a dark sky, it can be seen with the naked eye as a "fuzzy" patch of light. Its individual stars can be resolved with an ordinary pair of binoculars;

  • The second notable constellation this month is Cassiopeia, the vain Queen. When the Gods placed Cassiopeia in the sky, she was punished for her vanity by being tied to her throne and laid on her back. The five bright stars that make up the constellation's "W" or "M" shape makes it easy to identify;

  • A beautiful double star resides in the constellation. Eta Cassiopeiae can be spit into its gold and blue components with binoculars or a small telescope;

  • Alos located in Cassiopeia is the open star cluster M103. Look for the prominent red star near its center. Through a pair of binoculars, the cluster's fan shape is easily recognizable;

  • Situated between Perseus and Cassiopeia is the magnificent "Double Cluster". Seen as two close fuzzy patches of light with the naked eye, binoculars will reveal the glittering diamond-like stars of each cluster;

  • The early morning hours of December host the brilliant planet Venus. By mid month, the tiny planet Mercury joins Venus in the brightening predawn sky. A modest amateur telescope will reveal each planet deplaying Moon-like phases.;

  • On the nights of December 13th and 14th, the Geminid meteor shower makes its annual appearance;

  • To view the Geminids, watch the sky for streaks of light that radiate from the constellation Gemini (the Twins). After midnight, Gemini will be located in the southwestern sky, directly above the easily recognizable constellation of Orion the Hunter. If you can view them away from city lights and under a dark sky, you may see as many as 60 colorful meteors per hour.

Watch "Tonight's Sky" for December, 2018 graciously provided by the fine folks at HubbleSite.org:

We cordially invite you to

"Discover the Universe with The Big Sky Astronomy Club"