Night Skies - January Venus & Saturn in the January sky

Fred Barrett | Jan 08, 2009

by Leo Enright

In the month of January, sunsets continue to be in the very early evening, or maybe more correctly, in the late afternoon. At our latitude, the earliest sunset of the whole year was on December 10. Since that date, sunsets have been just very slightly later each day – by only a few seconds each day, actually, and the day-to-day difference in time has been scarcely noticeable. Only by mid to late January will our daylight hours be noticeably longer, as our sunset time moves from 4:33PM on New Year’s Day to 5:10PM on January 31. In the chilly January mornings, on the other hand, the difference in the day-to-day sunrise times will not even be that noticeable, since they range only from the 7:47AM sunrise on January 4 (the date of the latest sunrise, locally, of the whole year) to 7:31AM on January 31. In fact, our January sunrise times average only about a half-minute earlier from one morning to the next. How many readers enlivened their holiday conversation by informing their friends that, in this part of the world, the year’s earliest sunset is in early December, but the latest sunrise is in early January?

On crisp, clear January evenings we have the ideal time to watch the best array of bright stars of any time of the year – as this truly stunning array begins its march across the southern sky – and continues to do so during the entire night. The very large constellation Orion The Hunter dominates in the southeast, pursuing Taurus The Bull, with his canine companions Canis Major and Canis Minor following at his heels. Only with the onset of dawn does this remarkable group sink into the west and disappear. The outline of The Hunter is created by seven very bright stars, all having well-known Latin or Arabic names, Betelgeuse and Bellatrix, for his shoulders, Rigel and Saif for his knees, and Alnilam, Alnitak, and Mintaka to outline his belt, but astronomers find the hazy area in the stars below the belt, and sometimes called Orion’s Sword, or the Orion Nebula, the most fascinating area of the whole constellation, since it is an immense region of hydrogen gas where new stars are being generated – a fact we should recall each time we see this “hazy spot in Orion’s Sword” – either with the unaided eye or with binoculars or a telescope. Having identified these eight objects in the outline of Orion, we must not forget that the star Sirius, identified as the “eye of the big dog” in Canis Major, and well to the left from Orion’s Belt, is the brightest star in the whole sky, and Procyon, the star marking the head of the smaller dog, Canis Minor, is the sky’s sixth brightest star. Procyon is actually very close in brightness to two of Orion’s stars – just slightly fainter than Rigel, the brighter one of his “knee stars”, and just slightly brighter than Betelgeuse, the brighter one of his “shoulder stars”. Try to verify for yourself the order of brightness of these three stars.

Of the five bright planets, only four of them may be seen this month and only two of them may be seen for the entire month. Mars will not be seen this month because it is in approximately the same direction as the sun, and the glare of the sun will prevent our seeing it. Brilliant Venus will dominate the southwestern evening sky for a couple of hours after sunset – for the entire month. Careful observers will be able to notice that it appears a bit higher each evening as the month progresses – if they observe it at the same time each evening. As the month progresses, try to see how soon after sunset you can see Venus. Can you see it right AT, or even BEFORE, sunset? Also, if you observe it with a telescope, at what date does its phase appear exactly like that of a First Quarter Moon? Jupiter may be seen, also in the southwestern sky, but much lower than Venus and to its right, AND only for about the first week of the month, since after that it will appear lower and lower and be just too low to see for most observers. Mercury will appear very near Jupiter – and slightly below it, for the first few evenings of the month. With clear skies and a good view right down to the southwestern horizon, skywatchers who use binoculars for a short while beginning about 40 minutes after sunset have a chance of seeing both Jupiter and Mercury – but only if all of those conditions are satisfied and only for the first seven or eight days of the month.

The final one of the bright planets, Saturn, may be seen among the stars of the constellation Leo The Lion, just below the triangle of stars that form the hindquarters of the beast. Saturn rises in the east at about 10PM in early January and about 9PM in late January. Although Saturn is easily seen naked-eye or with binoculars, a telescope is suggested to appreciate the view of this planet, and the view of Saturn this month is quite remarkable. To some people who have seen Saturn previously, it may now appear like something they have never witnessed. On two occasions during Saturn’s 29-year orbit, the angle of that planet’s ring system is tilted such that the rings seem to disappear, or almost disappear, completely. We are now at that point in Saturn’s 29-year cycle, when the planet may look like Jupiter – with several moons orbiting it, but no rings visible. It is certainly a very different view of Saturn! Enjoy it if you get the chance!

A few lunar-planetary conjunctions are worth watching this month. In the predawn sky early on the morning of January 21, be sure to try and see the waning crescent moon low in the eastern sky beside the bright red star Antares, brightest star in the constellation Scorpius. On the three evenings of January 28, 29 and 30th, at about 45 minutes after sunset (at least before 6PM) start looking for the conjunction of the slim waxing crescent moon and the planet Venus – low in the western sky. On the 28th and the 29th, the lunar crescent is BELOW Venus, and on the 30th, it is ABOVE Venus. This is a good lesson in how far the moon appears to travel in one day as it orbits the Earth.

Much more information about observing winter constellations and other objects of the night sky is available in the latest edition of the book The Beginner’s Observing Guide, which is now available at Sharbot Lake Pharmacy. Best wishes for 2009, and remember to enjoy the beauty of the clear, dark, and unpolluted sky.

More information about observing the spring and summer sky is available in the book entitled “The Beginner’s Observing Guide” which is now available at Sharbot Lake Pharmacy.