You are hereTHIS MONTH'S SKY - February 2009
THIS MONTH'S SKY - February 2009
THIS MONTH'S SKY
Celestial Events -- February 2009
|As February begins, Mercury is already rising an hour before the Sun. Although the angle of the ecliptic in the eastern morning sky is low this time of year, Mercury can be spotted with care. Between Mercury and the Sun but for now unseen are Mars and Jupiter. Although Mercury does not get higher, over the next few weeks it brightens due to its increasing phase.
Meanwhile Jupiter, escaping from the Sun faster than Mars, becomes visible to the naked eye around mid-month. It passes the Red Planet on the morning of the 17th, when the two are only ½° apart (binoculars will be needed to see Mars).
On February 22nd a thin crescent Moon joins the fray. That morning Mercury is 4° below the Moon and 2° above Jupiter. With a telescope or binoculars Mars is seen to be 3° below Jupiter. On that date a telescope reveals two extra Jovian satellites -- the double star 19 Capricorni (both components magnitude 5.8). The entire lineup Moon and planets forms a rough straight line 8½ long.
The following morning Mercury and Jupiter are only 1° apart, Mars is 3¼° below Jupiter and a hairline crescent Moon is in turn 3° below Mars. The day after (the 24th) Jupiter passes a mere 40 arc minutes (two-thirds of a degree) above Mercury (the latter is getting difficult to see with the naked eye).
On the mornings of March 1st and 2nd, Mars and Mercury are only 40' apart, though binoculars will be needed to see them.
Jupiter and double star 19 Capricorni
|This month is the high point of the appearance of Comet C/2007N3 Lulin. The comet is expected to reach sixth magnitude this month, which would make it accessible to binoculars and telescopes in the city. Comet Lulin was discovered by 19-year-old student Quanzhi Ye at Sun-Yat Sen University in China from images taken on July 11, 2007 by Chi Sheng Lin of National Central University in Taiwan by a 16-inch telescope at Lulin Observatory in Taiwan.
The comet's orbit was determined and found to be highly favorable. On January 10th it was at perihelion, its closest point to the Sun at 1.2 AUs (1 AU = astronomical unit is the average distance of Earth from the Sun, around 93 million miles). Though it is now moving away from the Sun, it approaches Earth and continues to brighten (from our point of view) through most of February.
The comet rises about 2 AM on February 1st at magnitude 7.3 (comet magnitudes are educated guesses) in the middle of the constellation Libra the Scales. In the first week of the month, under dark skies it slowly brightens and moves west at about a degree per day. On the 6th is is less than ½° above the wide double star Zubenelgenubi (α Alpha Librae). The following week the Moon interferes as the comet enters Virgo the Virgin. On the 16th, now rising at 10 PM and moving at 3½° per day as it approaches Earth, Lulin has brightened to magnitude 6.3 and is less than 3° above Virgo's first-magnitude star Spica. Lulin's magnitude is predicted to peak at 6.0 from the 20th through the 25th of February as it becomes visible in early evening hours. Rising on the 23rd, it enters Leo the Lion only 2° from Saturn (the two will widen during the night). That day and the next the comet is at its closest (only 0.41 AU from Earth) and fastest, moving just over 5° in 24 hours. Early in the evening of the 27th at magnitude 6.2 it is less than a degree from Regulus, another first-magnitude star. In the next week the comet fades pretty rapidly as it enters Cancer the Crab. The Moon comes by to make viewing the comet and its conjunction with the Beehive Cluster (on March 5th) difficult.
If you haven't noticed, all this activity took place within the confines of the ecliptic, the path of the Sun and planets. So Comet Lulin lies almost exactly in the same plane. There is a difference though -- the planets all revolve around the Sun counter-clockwise (as seen from over Earth's North Pole), but Lulin moves clockwise. That's why it encountered the zodiac constellations (Libra, Virgo, Leo and Cancer) in reverse order.
Soon the comet becomes difficult to view, even with a telescope, as it returns to the depths of the Solar System, where it will remain for eons.
Comet Lulin at 5 AM
Comete Lulin at 9 PM
|Click to get sky charts and a description of the sky for this month.|
PLANETS IN FEBRUARY
MERCURY is visible in the morning sky for most of the month. Hardly visible as February begins, it brightens and moves farther from the Sun, reaching maximum elongation (26°) on the 13th. As it falls back towards the Sun, it meets first Jupiter and later Mars, as described above. The planets form beautiful gatherings with the Moon on the mornings of the 22nd and 23rd. Shortly thereafter it is too near the Sun to be seen naked-eye.
VENUS (magnitude -4.7 to -4.8, diameter 29.8" to 44.4", phase 41% to 20% lit) continues to dominate the early evening sky. It sets four hours after the Sun on February 1st and three hours later on the 28th. Venus is approaching Earth now, and is getting larger in a telescope, while its illumination decreases to a crescent.
MARS finally peeps out from behind the Sun, entering the morning sky late in the month, though it will still require optical aid. It spends much of the month near Jupiter. Use binoculars to hop to Mars from Jupiter or Mercury, which are nearby most of the month (above).
JUPITER (magnitude -1.9 to -2.0, diameter 32.4" to 33.1") like Mars becomes a morning object. Brighter and escaping from the Sun quicker than Mars, it becomes visible to the naked eye around mid-February. Its events are described above.
SATURN (magnitude +0.7 to +0.5, diameter 19.4" to 19.8") in Leo rises at 8:30 PM on February 1st and 6:30 PM on the 28th. Moving retrograde (toward the west among the stars) it is nearing opposition. Saturn's rings are still close to edge-on, although they're slightly more open than last month.
URANUS (magnitude +5.9, diameter 3.4") in Aquarius can be seen early in the evening in the first weeks of February, then is lost in dusk. On the 27th it reaches aphelion, its farthest distance from the Sun, an event that occurs only once in Uranus's 84-year orbit.
NEPTUNE (magnitude +8.0, diameter 2.2") is in conjunction with the Sun on the 12th. It enters the morning sky but is too close to the Sun to be seen in February.
PLUTO is low in the morning sky and a very difficult object to spot.
The MOON is at First Quarter on the 2nd. The next evening it passes by the Pleiades cluster, occulting Taygeta and narrowly missing a few other stars (movie). The Moon is full on the 9th, when a penumbral eclipse occurs for the western USA (resulting only in slight darkening of the southern part of the Moon, and in any case not visible at all from NYC). The Moon passes Saturn on the 10th and 11th. Last Quarter is on the 16th. On the 22nd a thin crescent Moon is just above Mercury and Jupiter; the next morning it is below the two planets and will require binoculars to spot. New Moon occurs on the 24th. Three days later, now in the evening sky, it passes only 1½° from Venus in an eye-catching display.
Asteroid 1 CERES is at opposition on February 25th. On that day it will be 147,167,000 miles from Earth, closer than any time between 1857 and 4164!
THIS MONTH'S EVENTS
(Times are EST)
|February 2||First Quarter Moon at 6:13 PM.|
|FEBRUARY 3||The Moon passes near the Pleiades tonight, occulting the star Taygeta from 9:20 to 10:13 PM (movie).|
|February 9||Full Moon at 9:49 AM. There is a penumbral eclipse in the northwest US.|
|February 12||Neptune is in conjunction with the Sun, entering the morning sky.|
|February 13||Mercury is at greatest western elongation (26°) from the Sun.|
|February 16||Last Quarter Moon at 4:37 PM.|
|February 17||Mars is less than a degree below Jupiter this morning (binoculars or telescope required).|
|FEBRUARY 20 - 27||This week Comet Lulin should be visible in the evening, with no interference from the Moon (see above).|
|FEBRUARY 22||A crescent Moon lies above Jupiter and Mercury this morning (see above). The Moon, Mercury, Jupiter and Mars form a straight line.|
|February 23||A very thin crescent Moon is below Mars (binoculars needed), Jupiter and Mercury (see above).|
|FEBRUARY 24||Mercury and Jupiter are closest, less than a degree, this morning (see above).|
|New Moon at 8:35 PM.|
|February 25||Asteroid 1 Ceres is at opposition, 1.58 AU (astronomical units) or 147,167,000 miles from Earth.|
|February 27||Venus is only 1½° from the crescent Moon this evening.|