Urban Observing December 2015 December 1, 2015Posted by aquillam in Astronomy.
This is a fantastic time for morning observers. Late sunrises give us either a little extra sleep, or a little extra observing time. And there’s quite a collection to observe: plenty of planets, a couple meteor showers, and maybe even a comet!
At about magnitude 6.5 on November 30, comet Catalina (C/2013 US10) is probably not going to be the comet of the century, but it should be a naked-eye object. It makes it’s closest approach to Earth on January 12, so it should slowly brighten between now and mid January. In December it passes through Virgo, ending up just below Arcturus in the pre-dawn sky. Use binoculars in the first week of December to catch the whole line-up in the ESE: The Moon, Jupiter, Mars, Venus, and comet Catalina.
While the end of November brings the end of fireball season, meteor watchers should not despair. Two strong meteor showers grace the December skies. Unfortunately, they aren’t good for urban sky watchers, so this is your excuse to get out of town for a few nights this month.
Beginning around December 4, the Geminids are often the strongest shower of the year. The peak, with a possible 120 meteors per hour, should occur on the evening/morning December 13-14. Gemini rises by 8 PM and transits around 3 AM in early December. This means the best time to observe is actually the midnight to 3 AM window, and observing as early as 10 PM is quite reasonable! Although the night of the 14th/15th should also be good, shower activity decreases rapidly after the peak, so take the first clear night you can to observe.
If you want to find out if someone is really dedicated to meteor showers, find out if they want to watch the Ursids. This relatively low activity shower picks up just after the end of the Geminids. The peak on the morning of the 21st or 22nd should boast 5 to 10 meteors per hour. However, occasional outbursts of over 25 meteors per hour have occurred, and it’s unclear why, so you never know what this shower might do. Given the position of the radiant in Ursa Minor, it is best viewed 2 to 5 AM.
The December solstice fall on December 21 at 11:48 PM in the eastern US (that’s 04:48 UT on December 22).
If you’re in the right area, there will be an occultation of Venus by the Moon on December 7! For many, it’s a daytime event, so you’ll need a telescope to observe it.
New December 11
Full December 25 (Santa should have plenty of moonlight to find your house!)
Mercury makes a brief foray into the evening sky near the end of the month. Look for it beginning around the 16th low in the southwest. Your best chance of spotting it will be the last week of December. It starts heading back toward the sun around January 2.
Although it has started it slow trip back toward the sun, Venus is still the brightest object in the morning sky. The late December sunrises mean you can look as late as 7 or even 8 AM (at the end of the month) and spot it. Look for it with an old moon on December 7 (even if you don’t see the occultation.) If you have a small ‘scope, check it out along with the double star Zubenelgenubi (I love that name!)
Mars is also a morning planet right now. Much fainter that its apparent neighbors, you’ll probably want binoculars. Look for it to make a nice pairing with blue Spica on December 23.
Jupiter rises before midnight on December 20, so technically it joins the evening skill this month. However, it’s best viewed in the morning for quite a while yet. It’ll be late January before it’s up at 10 PM. Look for a nice conjunction with a 3rd quarter moon on December 31.
Saturn peeks out from behind the Sun in the morning skies late this month. Look for it around 7 AM in the last week of December. Saturn makes a nice group with Venus any Antares around the 28 or so.