December night sights and the weekend forecast

Posted at 8:13 AM, Dec 04, 2020
and last updated 2020-12-04 10:39:02-05

Today's Forecast:
Bright sunshine and light wind will guide our day to highs into the upper 30s and low 40s in the region today. Those clear skies will help push daytime highs back above average during the day but will also allow lows to fall quickly to the low teens and single digits with a few areas falling back below zero at times.

BOZEMAN: High: 42; Low: 15. Short description of conditions for today and morning weather conditions.

BUTTE: High: 34; Low: 8. Clear skies throughout the day with chilly low temperatures tomorrow morning.

DILLON: High: 40; Low: 16. Short description of conditions for today and morning weather conditions.

WEST YELLOWSTONE: High: 32; Low: -3. Short description of conditions for today and morning weather conditions.

December is a special month for stargazers, and 2020 is extra special. We have several great views available for us. Here are a few of the more notable sights.

  • Dec. 10 (morning): A slender waning lunar crescent and Spica rise together less than 7° apart.
  • Dec. 12 (dawn): An even thinner lunar crescent pairs closely with Venus. The Moon occults (covers) the planet during late morning or early afternoon as seen from western North America, Alaska, and Hawaii — use binoculars to see it.
  • Dec. 12 (dusk): Jupiter and dimmer Saturn remain within 1° of each other low in southwest until Dec. 29th.
  • Dec. 13 (night): The Geminid meteor shower peaks tonight, with up to 1 meteor per minute seen from clear, dark locations (no interference from the Moon). Start looking as early as 8 p.m. local time. Source is asteroid 3200 Phaethon.
  • Dec. 14 (day): A total solar eclipse will be visible along a narrow path that crosses Chile and Argentina. Much of South America will see partial phases, though none of it is visible from North America.
  • Dec. 16 (dusk): Look low in the southwest for a two-day-old lunar crescent 5° below the close pairing of Jupiter and Saturn.
  • Dec. 21: Solstice occurs at 5:02 a.m. EST (2:02 a.m. PST), marking the astronomical start of winter in the Northern Hemisphere and summer in the Southern Hemisphere. On this day, the Sun is directly overhead at midday as seen from Earth’s Tropic of Capricorn.
  • Dec. 21 (dusk): Jupiter and Saturn are only 1/10° apart. Look low in southwest beginning 45 minutes after sunset. Use binoculars or a small telescope to separate them. A pairing of Jupiter and Saturn this close has not occurred since 1623.
  • Dec. 23 (evening): The waxing gibbous Moon and Mars are 5½° apart.
  • Dec. 26 (evening): A fatter Moon is about halfway between the Hyades and Pleiades open star clusters.
  • Dec. 30 (evening): The waning gibbous Moon has come full circle since Dec. 3 and is back in Gemini, about 4° to the right of Pollux.