The Sky This Week, 2013 January 2 - 8
Orion and surroundings
The Moon wanes in the morning sky as the first week of the new year ticks by. Last Quarter occurs on the 4th at 10:58 pm Eastern Standard Time. The waning gibbous Moon all but wipes out the annual Quadrantids meteor shower which is expected to peak before dawn on the morning of the 3rd. This shower, whose radiant appears high in the northeast in the wee hours, has been known to produce intense but brief bursts of activity for a couple of hours around its predicted peak. This year the peak occurs after sunrise on the east coast, so our chances of seeing a burst are quite slim. Look for the Moon just five degrees west of the bright star Spica before dawn on the 5th. On the mornings of the 6th and 7th she glides below golden Saturn in the gathering glow of twilight.
Earth reached its closest point to the Sun on New Year’s Day at 11:38 pm EST. At this time, known as "perihelion" to astronomers, the distance separating the center of the Earth from the Sun was just over 147 million kilometers (91,403,000 miles). We will now gradually draw away from Old Sol until July 5th, 2013, when we reach aphelion at a distance of 152,097,000 kilometers (94,509,000 miles). This small variation in distance from the Sun is one of the reasons our fair planet enjoys a mostly benevolent climate. However, over time (hundreds of thousands of years) the eccentricity of our orbit slowly varies thanks to the influence of the other planets, mostly Jupiter. That said, even these extremes don’t vary that much from a circular orbit.
For those of you who don’t like waking up in the dark each morning, take heart. The latest sunrise of the year occurs on the 4th. Here in Washington Old Sol rises at 7:27 am EST. By next week he’ll start to retreat to earlier times leading to brighter morning hours.
Winter’s bright constellations are now hitting their stride in the evening sky. Orion and his cohorts are well up by the mid-evening, and the meridian bisects the Great Winter Circle by 11:00 pm. Orion is the centerpiece of the annual "Globe At Night" observing campaign, an international "citizen science" project intended to help chart the spread of light pollution around the globe. The program is easy to participate in: just find Orion in your local sky, count the number of stars you see in the constellation, and report your findings via the Globe At Night website. This is the first of five GAN campaigns for the year, and you are encouraged to report as many times as you wish, preferably from several different sites. It’s a great way to learn the stars and a good excuse to seek out dark observing sites.
2013 opens with ruddy Mars still visible in the early evening low in the southwest as evening twilight fades to darkness. The red planet is finally losing ground to the advancing Sun, though, so you need to be out shortly after sunset to see him. He’s now drifting through the dim stars of Capricornus, so he’ll be the brightest object in his little patch of sky.
Jupiter opens the year in a prime spot in the evening sky, crossing the meridian just before 10:00 pm. You should have no trouble spotting the giant planet even though he is accompanied by the brightest of winter’s stars. Old Jove is slowly drifting westward against the background of the northernmost stars in the Hyades star cluster. This means that he offers a great view even in a pair of binoculars, but a telescope really shows him to best advantage. In my portable 80mm (3.1-inch) refractor at low power he is framed by the brighter stars of the cluster, and his four bright moons seem to be gathered around him for safety. At 100 power the moons are more spread out and the planet’s prominent cloud belts are easily seen. My 200 mm (8-inch) scope brings out a wealth of detail in the cloud belts, including the famous Great Red Spot. For those of you who would like to glimpse this Earth-sized storm in Jupiter’s atmosphere, point your telescope toward him at around 9:00 pm on the evenings of the 2nd and 7th. On the latter night you’ll also see a very interesting configuration of three of the planet’s Galilean moons.
The morning sky is graced by Saturn, whose warm yellow glow should be easy to spot in the southeastern sky at around 6:00 am as the first rays of twilight appear. The ringed planet is about 16 degrees east of the bright blue star Spica and contrasts nicely with the star. The Moon is nearby Saturn before dawn on the 6th and 7th. The planet’s rings are tipped favorably toward us this year, so your view of him through the telescope will invariably look "just like the pictures"!
Bright Venus is now visible only during the gathering morning twilight. She is bright enough to be easily seen, but you’ll have to look on a clear morning free from haze and horizon clouds.