The Sky This Week, 2017 January 31 - February 7
|The Moon, Venus, and Mars by the USNO flagpole,
imaged 2017 January 30
with a Canon EOS Rebel T2i DSLR
The Moon greets evening skywatchers, waxing as she climbs the ecliptic towards the bright winter constellations. First Quarter occurs on the 3rd at 11:19 pm Eastern Standard Time. Luna starts the week in the vicinity of bright Venus and ruddy Mars. When twilight fades on the evening of the 5th you’ll find Luna just one degree from the bright star Aldebaran in Taurus, the Bull. As the evening progresses watch the Moon drift eastward from the red-hued star.
Forget the Super Bowl; the truly significant event of early February is Groundhog Day, one of our more popular "semi-holidays". It is similar in character to Halloween in that most everybody is aware of it and "observes" it in some fashion, but they’re not really sure why they do. We’re all familiar with the annual ritual of a group of nattily-dressed gentlemen in top hats and tails gathered on a small hilltop in rural Pennsylvania to await the outcome of a certain large indigenous rodent’s ability to "see his shadow" and therefore predict the coming of spring. Once a year atop Gobbler’s Knob in Punxsutawney, PA the eyes of the world settle on Phil the Groundhog as dawn breaks. If Phil casts a shadow, then there will be six more weeks of winter, and if he doesn’t, well, there will still be six more weeks of winter! Groundhog day falls mid-way between the winter solstice and the Vernal equinox, and since the average season is 12 weeks long the answer either way is a sure bet. Despite the modern exploitation, the roots of Groundhog Day date back well over a thousand years to a Celtic feast called Imbolc, which celebrated the coming of spring and the beginning of the "lambing season". The spread of Christianity then linked it to the feast known as Candlemas which celebrated the presentation of the infant Jesus at the temple 40 days after his birth. This was one of the so-called "cross-quarter" days of ancient timekeeping tradition, which, along with the quarterly seasonal markers, were the dates when serfs paid rent to their feudal lords. Halloween is the other cross-quarter day that’s still widely observed here in America, and Europeans still observe May Day. Lammas, the final cross-quarter day, falls on August 1st, which is the traditional start of summer vacation days in many parts of the world.
This is a great week to observe the Moon, especially if you have a new telescope to try out. Luna’s motion along the ecliptic takes her on a high arc through the winter constellations, and she presents ideal phases to gradually reveal new detail with each passing night. The stark lighting on the Moon’s battered landscapes offers mute testament to violence that formed the solar system. It’s hard to believe that the surface of the Earth once looked like this, but billions of years of erosion by wind, rain, and plate tectonics have all but wiped out these features on our fair home planet.
Venus dominates the early evening sky, beaming down in the southwestern sky shortly after sunset. If you know where to look you can even pick her out during the daytime, especially in the hour or so before sunset. She is now glowing at her brightest for this year’s evening apparition. Through the telescope she now has a distinct crescent shape.
Mars keeps pace just east of Venus, separated from the dazzling planet by about five degrees. Despite the fact that Venus is over 100 times brighter than the red planet, his ruddy hue still makes him a distinctive sight.
Jupiter now rises at around 11:00 pm and should be easily seen in the southeastern sky by midnight. Your best view of him is still just before dawn, where you’ll find him high in the south in the company of the bright star Spica. Jupiter reaches the first stationary point of this year’s apparition on the 6th.
Saturn is also best seen in the pre-dawn sky. If you’re up an hour before sunrise look for the ringed planet about 15 degrees above the southeast horizon.