SCAS / Southern Colorado Skies / December 21 – 26, 2015

Consider a planetarium program to help you plan your observations. There are many commercial products available, and a very good program (Cartes du Ciel) is available free at


Comet Catalina (C/2013US10) is still in view as I mentioned in last week’s blog post. It’s in the east just before sunrise but it will move higher during the next few weeks. Right now it’s at a relatively faint Magnitude 6.36 (at least binoculars are required). It’s approaching Arcturus and should be very close to Arcturus on January 1st (happy new year!). (For more information see Using binoculars, the comet should appear as a small fuzzy patch of light. [The photo was taken on December 6, 2015, by Brian D. Ottum in Rancho Hidalgo, New Mexico.]comet-catalina-12-6-2015-Brian-D-Ottum-Rancho-Hidalgo-NM-e1449680049755


Also note that M31, the Andromeda Galaxy, will pass near the zenith (nearly straight up in the sky) a little after dark. If you haven’t yet seen it yet, it’s easy to spot in binoculars or a small telescope (in really dark skies no optics are required to spot it as a faint fuzz-ball). M31 is a spiral galaxy about 2.2 million light-years from Earth; it’s about 200,000 light-years in diameter and is on a collision course (in the far, far distant future) with our Milky Way Galaxy.M31-50

Monday (December 21)

Solstice begins at 9:48 p.m. MST. This is the longest night of the year in the northern hemisphere.

Tuesday (December 22)

The bright (waxing gibbous) Moon is in Taurus, near Aldebaran and the Pleiades.

Mars passes just north of Spica as this planet continues its early morning dance with several other planets (see below).

Thursday (December 24)

The nearly full Moon shines brighter than normal tonight, as it is closer to perigee (its closest point to Earth) than average. Look for it to the upper right in Orion, at the tip of Orion’s “club.”


Mercury (in Sagittarius)

Look for shy Mercury about 30 to 45 minutes after sunset in the low west-southwest. You may need binoculars (be cautious of the setting Sun!). It’s getting higher every day!

Venus (in Libra), Mars (in Virgo), Jupiter (in Virgo), and Saturn (in Scorpius)

Still-bright Venus keeps company in the pre-dawn eastern sky with Mars. Jupiter, and Saturn. Saturn is just now joining the party, however, and may be difficult to see far to the lower left of Venus – binoculars may help but be cautious of the rising Sun!

Uranus (in Pisces)

High in the southern sky by early evening.

Neptune (in Aquarius)

High in the southern sky by early evening.

Iridium Flares and International Space Station (ISS):

Sorry – these are too numerous to list here! If you’re serious, load the ISS DETECTOR app on your smart phone or tablet. Alternatively, refer to SCAS member Chuck Percival’s column in the Sunday Pueblo Chieftain.

Have fun!

Dave Furry, President SCAS

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