A Gem of a Meteor Shower and Maybe a Naked-eye Comet

December 2015  :  Dave Huestis

Usually I’m complaining about the weather and how it affects our astronomical observations in southern New England. However, local stargazers were more fortunate during the second half of this year.

The annual Perseid meteor shower back in August performed reasonably well. It wasn’t spectacular, but clear skies during most of peak night on August 12-13 provided shooting star watchers with dozens of bright meteors blazing across the sky.

And the best event was the total lunar eclipse on the night of September 27-28. A low pressure weather system was slowly moving up the Atlantic coast, but high pressure to our northwest strengthened and kept the clouds from encroaching upon our little corner of the universe. We were able to watch this beautiful eclipse in its entirety.

I hosted an eclipse party at Bryant University for my astronomy lab students as well as the entire campus community. Three Skyscrapers members (Jim Brenek, Alex Bergemann and yours truly), along with my brother Glen Huestis and Rebecca Rowley from the Greenville Public Library, shared our love of astronomy with more than 100 students. Collectively we provided five telescopes of various designs and apertures, along with several binoculars, for students to observe this eclipse.

One of my lab students, Justin Dauley, in his observing report said in part, “… I preferred to just turn my eyes to the sky and observe the old fashioned way. By totality, the moon looked like something from a science fiction movie, and I couldn’t help but wonder what ancient civilizations would think when an event like this occurred. This thought lead me to the realization that events like this were probably the reason that many ancient peoples worshipped and highly respected the skies and heavens because of how powerful they are to watch. Even though we know what is happening, an event like a total lunar eclipse is still so majestic.”

I’m hoping our good luck will continue for the month of December, for there are several notable sky events that will lure us out to enjoy under the sky dome.

Last month I mentioned there was a comet making its first journey through the inner solar system. Prior to November 15, Comet Catalina (C/2013 US10) had been only been seen from the southern hemisphere. Since I am writing this column before that date, I will provide updates to the local news media so you may share in its beauty should this comet become a naked-eye object as it emerges from the solar glare in the pre-dawn sky.

Meanwhile, December’s pre-dawn sky still showcases three planets. Venus is the brightest one closer to the horizon. Jupiter is the second brightest object above the southeastern horizon. Dim red Mars is between them. Comet Catalina (should it attain naked-eye visibility) will be 13 degrees to the lower left of Venus on December 1st. If you can’t locate it, try using a pair of binoculars. Each morning the comet will rise higher above the horizon and towards the left, becoming dimmer each morning. On the 4th the waning crescent Moon will be approximately three degrees to the lower right of Jupiter. Then on the 7th Comet Catalina will be approximately four degrees, about eight full Moon diameters, to the left of Venus. At that time a very thin crescent Moon will be just above and to the right of Venus. This alignment is one of those astronomical photo opportunities that shouldn’t be missed. A good horizon with a low tree-line will be a necessity.

Later that same day, during the early afternoon, the Moon will occult (pass in front of) Venus. Since the occultation occurs during broad daylight, you’ll need to locate them in binoculars or by using a computerized telescope. Venus will disappear along the Moon’s sunlit limb (edge) at about 12:43 p.m. approximately 14 degrees above the west-southwest horizon. Venus will reappear along the Moon’s dark limb at about 1:49 p.m. when it is just three degrees above the horizon. The key to observing this event is selecting an observing location with an unobstructed view towards the west.

As we move into the second week of December, Mercury will pull out of the solar glare in the southwest sky after sunset. Each night it will be farther from the sun and higher above the horizon. If you have difficulty trying to spot it, on the 12th Mercury will be below and to the left of the waxing crescent Moon. The planet will continue to climb higher into the evening sky until just after month’s end when it will begin to set earlier each night as it swings back towards the Sun from our perspective.

Furthermore, as the title of this column suggests, stargazers of every experience level will be treated to a gem of a meteor shower this month. On the night of December 13-14, the annual Geminid shooting star display will grace our skies. And since a very thin waxing crescent Moon will set early at around 6:45 p.m., interfering moonlight will not compromise the number of meteors to be seen. This situation is ideal because Gemini is well above the east-northeast horizon by 8:00 p.m., thereby allowing for a good number of meteors to be seen during the early evening hours. So if you have to work the next morning (peak is on a Sunday night to Monday morning), you can still catch a decent number of shooting stars before retiring for the night.

To see this meteor display to best advantage you should choose an observing location as far from interfering light pollution as possible. Do not remain standing too long to observe this display. Either sit or recline in a comfortable chair. Dress in layers. Climb into a sleeping bag if possible. Wear a hat to keep heat from escaping through your head. Wear warm mittens, not gloves. Mittens keep your fingers together for added warmth. You can also use a few of those pocket warmers to keep extremities toasty.

While the Geminids appear to emanate from Gemini near its brightest stars, Castor and Pollux, scan around the sky as much as possible. As the night progresses and Gemini moves across the sky towards the west, your scan should move as well. At around 2:30 a.m. Gemini will be on your meridian, just south of zenith. With clear and dark skies a keen-eyed observer should see 60+ meteors per hour during the peak activity between midnight and dawn. If you care to conduct an accurate count, you should notice the number of meteors per hour increase as the night progresses, and then begin to decrease as dawn approaches.

The Geminids are fairly bright and moderate in speed, hitting our atmosphere at 21.75 miles per second. They are characterized by their multicolored display (65% being white, 26% yellow, and the remaining 9% blue, red and green). Geminids also have a reputation for producing exploding meteors called fireballs.

I can’t believe how quickly 2015 has passed. Another important astronomical event, the Winter Solstice, occurs on December 21 at 11:48 p.m. EST. The Sun reaches its southernmost position in our northern hemisphere sky on this date. Take note of the low arc it traverses across the sky. After the solstice the sun will then begin its daily migration northward and the daylight hours will lengthen as we head towards the Vernal Equinox (Spring) on March 20, 2016, at 12:30 a.m. EDT.

Despite the cold and snowy season that is almost upon us, as long as the local Rhode Island observatories’ grounds are accessible, the telescopes will be available for you to explore the heavens. Knowledgeable sky interpreters will be on hand to introduce you to a variety of celestial wonders. Be sure to visit each website prior to setting out for a field trip to these facilities, as wintry conditions can force unexpected closures.

Seagrave Memorial Observatory in North Scituate is open to the public every clear Saturday night. Ladd Observatory in Providence is open every clear Tuesday night. The Margaret M. Jacoby Observatory at the CCRI Knight Campus in Warwick is open every clear Wednesday night. Frosty Drew Observatory in Charlestown is open every clear Friday night year-round.

Happy holidays and clear skies to all.