Jeff Green | Jan 25, 2007
Night Skies - February 1, 2007
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A Mercury sighting opportunity in the February sky ----------------------------------------------------------------------------------------------- by Leon Enright
The month of February always provides a chance to continue our evening views of the spectacular winter constellations of the southern sky along with the less spectacular emerging spring constellations in the eastern evening sky. In addition, this month, we have the chance to see all five of the bright naked-eye planets, though two of them will be difficult to see for part of the month.
The Great Hunter of ancient mythology, Orion, still marches across the southern sky in the evening. Most readers by now should be very familiar with his distinctive outline of very bright stars, with seven luminaries marking the shoulders, knees and belt of this giant figure. In addition, a huge circle of six stars surrounds him, almost filling the southern sky: Sirius and Procyon, to his left, marking the presence of the two dogs following faithfully on his heals, Castor and Pollux, the Heavenly Twins, to his left and well above the dogs, Capella the Goat Star, with her accompanying Kids Stars well above Orion’s head, and on his right beyond the stars marking a shield held in his left hand, the cluster of stars called The Hyades or The Head of The Bull dominated by the bright red star called Aldebaran. Some people complete the great circle with the brilliant star Rigel, seen as one of Orion’s knees, making it actually a ‘circle of seven’, unless they count the Twin Stars (Castro and Pollux) as a single object. In all, the 14 stars just mentioned (the principal luminaries of Orion and his neighbours) are among the very brightest of the stars to be found in any part of the entire sky. Two of Orion’s stars (Betelgeuse and Rigel) are among the sky’s ten brightest. Among his “surrounding circle” of stars, Sirius is the sky’s brightest of all, and the other five are among the 25 brightest, on a list that includes a number from the southern sky which are never seen at this latitude. Little wonder that even the most experienced skywatchers never tire of this display of heavenly brilliance.
Observing the planets will be particularly interesting this month. Shortly after sunset any casual observer with a decent view of the southwestern sky will quickly notice the brilliant planet Venus easily outshining any star, and visible before any star is visible. Careful observers may be able to spot this planet right at sunset, or even before sunset, and they will also notice as the month progresses, that Venus appears gradually higher and higher in the sky when it first becomes visible, and that it sets slightly later each evening. The solar system’s most elusive planet, Mercury, the one which many people have never in their lives seen with certainty, is also visible and easily found DURING THE FIRST TWO WEEKS of this month. Within that time look downward and to the right from Venus by about the width of your fist held at arm’s length. That will be about the average apparent separation of the two planets, but the separation around February 4th will be only about half that distance. Try for multiple observations to record the varying apparent separation between the two planets, and relish this infrequent chance to have a positive sighting of “the fleeting planet”, Mercury. The “all-night” planet this month is Saturn, which rises in the east at sunset, is highest in the south at midnight, and sets at sunrise. In the late evening it is seen well up in the east and above the star Regulus, brightest star in the constellation Leo the Lion, by about the width of a fist at arm’s length, though careful observers will note that the distance between them is somewhat less than that in the first part of the month, and it very gradually increases during the month. Owners of small telescopes will be thrilled also with the views of Saturn’s rings and the brightest of its many moons. The two planets, Jupiter and Mars, appear this month only in the morning sky, with Jupiter rising in the east at about 3:30 a.m. in early February, and a bit earlier each day until its rising time reaches 2 a.m. by month’s end. This brilliant planet, second only to Venus in brightness, may be seen to the left of the red star Antares, brightest star in Scorpius. Careful observers will note that the distance between the planet and the star slowly increases over the month. The red planet, Mars, is seen well down and to the left from Jupiter in the twilight hour before sunrise, but because it is much fainter than Jupiter and appears in the glow of morning twilight, many observers may miss seeing it unless they use binoculars to scan the sky just above the east-southeastern horizon at that time.
The moon’s conjunctions with the bright planets are especially notable this month. In the late evening on the first three days of February, there is a fine chance to see the moon’s daily progress in its orbit around the earth by noting its passing by Saturn and the star Regulus. On February 1, the near Full Moon appears above Saturn; at the same time on the 2nd it is between Saturn and Regulus; and on the 3rd it is below Regulus. Note the waning gibbous moon in the late evening on February 7 when it is very close to Spica, brightest star in Virgo. The eastern morning sky just an hour before sunrise provides interesting conjunctions on February 11 and 12; on the 11th the Last Quarter Moon appears to the right of brilliant Jupiter and the star Antares, and on the 12th it is seen below them. On the following two mornings, that is, on the 13th and 14th, a much thinner crescent may also be seen even further below and to the left from Jupiter and Antares. Following New Moon on February 17, the waxing crescent provides several beautiful sights for those who have a good view of the western evening sky. Between 40 and 60 minutes after sunset on the 18th skywatchers should remember to enjoy the striking view of the razor-thin crescent below Venus in the western sky. On the following two evenings also at the same time, that is, on the 19th and 20th the slightly thicker crescent will appear above brilliant Venus. Don’t miss these three striking arrangements of the night sky’s two brightest luminaries. You will surely want to show them to your friends and neighbours. On the evening of the 23rd, the waxing crescent moon passes very close to the Pleiades Star Cluster, also called The Seven Sisters, providing yet another outstanding naked-eye view involving the moon and bright celestial objects!
Much more information about observing the winter constellations and other objects of the night sky is available in the latest edition of the book, The Beginner’s Observing Guide, currently available at Sharbot Lake Pharmacy. Remember to take the time to enjoy the sights of the many beautiful objects in this month’s night skies.