Highlights for the December Night Sky

Brought to you by: Bob Haskins @ Waterville Estates

Do your part and help preserve the dark skies that we are fortunate to have

in Waterville Estates. Turn off all unnecessary outdoor lighting

Go outside tonight and discover the night sky


The Planets: “Evenings on the Ecliptic” The planets all follow an imaginary path in the sky called the ecliptic.

The glorious parade of bright planets, that we enjoyed watching over the summer and early fall, has ended.

Saturn – Will also soon be exiting the scene. Our ringed planet starts the month setting about two hours after sunset in the SW, however after the middle of the month it will be lost in the afterglow of the setting Sun.

Mars – Can be spotted all month long beginning at dusk and all through the night. Look for the “Red” planet halfway up in the sky in the south.

Venus – If you are up just before sunrise look for bright Venus in the SE.

Geminid Meteor Shower – Look for the meteors emanating from the constellation Gemini “the Twins”. See the write-up below for more details.

Comet “Wirtanen” – An emerald green comet is fast approaching the Earth. No guarantees on visibility. watch the  news for updates.


Stars and Constellations:

The cycle of the seasons is almost complete. The summer constellations are setting in the west just as the winter constellations are rising in the east. As the month progresses, Orion “The Hunter”, the most popular of the  winter constellations, rises in the east. In the northeast, the bright star “Capella”, which means the “goat”, shines brightly along with her three little companion stars which are referred to as her kids. They are part of the constellation Auriga  the “Charioteer”. Check out Capella with your binoculars to get a good view of the “kids” (refer to diagram). Also look to the north for Cassiopeia, upside down W” and the Big Dipper which should be near the horizon.

Turn to the west and see the curtain coming down on the stars of the “Summer Triangle”. Vega and Altair are starting to disappear toward the horizon followed by Deneb.

On the nights of December 13 and 14 the strong and reliable Geminid meteor shower will be visible. It will peak just before dawn on the 14th but should also be fairly active the night before and after. The Geminid shower is the richest and most reliable shower of the year, and it seems to have strengthen over the past years. The moon will not be a factor. The meteors will be coming out of the northeast.

The Winter Solstice arrives on December 21st. This is the longest night of the year in the Northern Hemisphere and marks the start of our winter. At this time, we in the north are leaning away from the Sun and the Sun has reached its southern most excursion on the ecliptic and is directly overhead at the Topic of Capricorn in the Southern Hemisphere. They are enjoying their longest day and it is the start of their summer. Many cultures in the Northern Hemisphere hold festivals of light to symbolize cheer and hope in this season of the shortest days.


Factoid of the Month:

Why does the moon always present the same face to us?

Our lunar companion rotates while it orbits the Earth. It’s just that the amount of time it takes the moon to compete a revolution on its axis is the same it takes to circle our planet – about 27 days. As a result, the same lunar hemisphere always faces Earth.


Astronomy News:

The mystery deepens. A few months ago I reported about an asteroid like object that had suddenly turned up in our Solar System. It was only around briefly. At first astronomers thought it was an asteroid or comet. They then determined that it was something from beyond our Solar System – a rare event. On the way out of our Solar System, something unexpected happened. “Oumuamua”, as it was named, accelerated as if jets of gas were pushing it forward. If it was not an asteroid or comet what was it? A  Harvard  group has just issued a paper saying Oumuamua  acted as if it were a “light sail” which is an object that is powered by light that reflects off an extremely reflective surface.


Astronomy Websites to explore:

  • heavens-above.com (satellites that are passing overhead)
  • gov
  • com
  • nasa.gov (sign up for alerts for the International Space Station passing overhead in your area)
  • com (The evening sky map for the month)