Have you ever used the Moon to find the bright stars and planets? Each month the Moon passes by all of all of the planets and some bright stars. This month you can see all five visible planets: Jupiter, Saturn, Mars, Venus, and Mercury. The bright stars Fomalhaut, Aldebaran, Capella, Regulus, Castor, Pollux, Spica, Procyon, Rigel and Betelgeuse can be easily found. If you have never seen the planets you may want to give this a try. No star maps, you just need to find the Moon. The best times to look are 30 minutes after sunset or when the Moon in is the morning sky about an hour before sunrise.
On Dec 1 the moon will be will south after sunset (4:36 PM MST for Aurora, CO). The star well below the Moon, and a touch east, is Fomalhaut, the brightest star in the constellation Piscis Austrinus, the Southern Fish.
On Dec 2 after sunset the moon is at first quarter (half moon) and will have move to just above Fomalhaut. When the Moon is at first quarter it is approximately in same place in space as the Earth and you were 3.5 hours ago.
On Dec 5 after sunset look for the very bright star to the east of the waxing gibbous moon, it’s Jupiter. Tonight, and for the next several days, Jupiter is on the border of the constellations Aries the ram and Pisces the fishes.
On Dec 6 the Moon will have passed over Jupiter. The distance between Jupiter and the Earth will increased by 8 million miles in one day.
On Dec 8 look east after sunset. A near full moon will be above and west of the bright star Aldebaran the brightest star in Taurus the bull. Just above the Moon is a small group stars called the Pleiades or seven sisters. It may be difficult to see with the Moon’s glare, but otherwise a great view in binoculars. The Moon will be in between Jupiter and the bright star Capella in the constellation Auriga the charioteer forming a wide flat “V”.
On Dec 9 look east after sunset. An almost nearly full Moon will have move to the east side of Aldebaran. The Pleiades will be above and to the west of the Moon.
On Dec 10 the Moon is full. The moon rises (4:52 MST for Aurora) as the Sun sets (4:35 PM MST for Aurora). You can tell the Moon is full because full moons always rise as the suns sets usually within 20 minutes (17 minutes this month) but can be longer. Even though the Moon may look full on Dec 9, it will rise 52 minutes before sunset. A full moon is technically only for a moment in time (7:36 AM MST for Aurora). The Moon is now on the morning side of the Sun. Up until now the Moon has been moving away from the Sun and seen only in the evening. From now to new moon the Moon will be moving toward the Sun. The Moon will only be visible in the evening sky after sunset for the next few days, but can be seen in the morning sky for the next two weeks. December’s full moon is call the Cold Moon, Yule Moon, Moon Before Yule Moon, Christmas Moon, and Oak Moon. If you look west between 6:00 AM and 6:30 AM MST you will see a partially eclipsed Moon. For more information go here.
On Dec 11 the full moon can be scene setting over the mountain at 8:01 AM MST. Start watching around 7:00 AM MST and note the Sun rising (7:10 AM MST for Aurora) as the Moon sets.
On Dec 12 after 9:30 PM MST look east. The waning gibbous moon is in Cancer and the middle of a group of bright stars. To the upper left of the Moon are Pollux (lower) and Castor (upper) in the constellation Gemini, the twins. Below and to the right is Procyon in Canis Minor, the little dog. Moving further to the right Sirius the brightest star in the sky is just above the horizon. It is in the constellation of Canis Major, the big dog. Above Sirius and to the right of the Moon is the constellation Orion. The three stars forming a near vertical line is Orion’s belt. To the left of the belt is the red giant Betelgeuse. To the right of the belt is the spectacular blue giant Rigel.
On Dec 15 start watching the Moon in the morning about an hour before sunrise (7:13 AM MST for Aurora). Look south about an hour before sunrise. The Moon is to the right of Mars. Between the waning gibbous moon and Mars is Regulus the brightest star in Leo the lion.
On Dec 16 the Moon will have moved between and below Mars and Regulus.
On Dec 17 the Moon is below Mars and at third quarter (half moon). At this phase the Moon is approximately in the same place in space the Earth and you will be in 3.5 hours. Note how the Moon plunges toward the Sun for the next six days.
On Dec 19 a waning crescent moon, Spika, the brightest star in the constellation Virgo the virgin, and Saturn will be in a line in the south eastern sky. Look about an hour before sunrise (7:16 AM MST for Aurora). Saturn is almost one billion miles away.
On Dec 20 a crescent moon will below Saturn with Spika to the right of Saturn. This grouping is called a conjunction.
On Dec 22 a thin crescent moon will be to the right and above Mercury low in the east. Best time to see this is one hour before sunrise (7:17 AM MST for Aurora). When the Moon is this close to the Sun, solar glare from the rising Sun starts to affect seeing. Mercury is most difficult planet to see because it is so close to the Sun. Unlike Jupiter where we can see it for hours a night, Mercury’s window is an hour at best. After 6:40 AM MST Mercury will start to be lost in the sunrise glare.
On Dec 24 the Moon in new. The new moon rises and sets with the Sun and cannot be seen.
On Dec 25 sorry kids there will be no Moon to see in the evening. Point that new telescope to the bright star in the south east, it’s Jupiter. The bright star low in the West at Sunset is Venus.
On Dec 27 a thin crescent Moon will be above the plant Venus.
On Dec 28 to Dec 31 watch the crescent moon thicken as it moves away from Venus toward Jupiter.
Check back next month to see what the Moon passes by. You will begin to notice a pattern that was common knowledge over two hundred years ago.