Skywatching February 2013

Orion the Hunter is visible in the southern
skies during the early evening hours of February.
(NASA photo)

Sun

Daylight rapidly increases during February.  On the first day of the month, the sun is in the sky for slightly over 10 hours.  By month’s end, daylight lasts for nearly 11.3 hours.  The net gain during the month is 80 minutes.

Moon Phases

Phase	Date	Moonrise	Moonset
Last Quarter	Feb 3	12:28 a.m.	10:45 a.m.
New Moon	Feb. 10	6:41 a.m.	6:10 p.m.
First Quarter	Feb 17	11:11 a.m.	1:24 a.m.  (02/18)
Full Moon	Feb 25	5:50 p.m.	6:31 a.m. (02/26)

Times from the U.S. Naval Observatory

Evening Sky

Mercury makes its best appearance of the year in the western evening sky.  Because it appears in the west for a short time after sunset, viewers need a good horizon and a clear western sky.  Mercury passed behind the sun (superior conjunction) on January 18, moving east (evening) of the sun.  It has been emerging from the sun’s glare since.

On February 8, Mercury passes within a full moon diameter (0.3 degrees) of dimmer Mars.  With the view of a clear horizon, look for the pair about 30 minutes after sunset through binoculars in the west-southwestern sky.

On the evening of February 11, the moon passes 6 degrees to the upper right of Mercury as shown in the chart above with planet and moon displayed at 6 p.m. CST.

On February 16, Mercury reaches its greatest angular separation ( greatest elongation) (18 degrees) from the sun as seen in our skies.  This makes it the best evening appearance of the year as seen from the Chicago area and the northern mid-latitudes.  Mercury appears in the evening sky three times this year and three times in the morning sky.  The best morning appearance for the Chicago area is in mid-November.

The chart above shows Mercury at sunset during its greatest eastern elongation with its invisible orbit sketched in the view.  The planet has reached a place on its orbit where it appears farthest away from the sun.  Mars is below Mercury.

Mercury is rarely visible in a dark sky, usually setting during twilight in its evening appearance or rising during early morning twilight at its morning appearance.

Jupiter is a the dazzling “star” visible high in the southern skies during the early evening hours throughout the month.  At mid-month, the moon passes Jupiter.  On February 17, the moon is 5 degrees to the lower right of Jupiter.  On the next evening, the pair is separated by nearly 7 degrees.

Jupiter is in front of the stars of Taurus with its bright star Aldebaran and two bright star clusters:  Pleiades and Hyades.  Look at the clusters through binoculars on evenings when the moon is not in that part of the sky.

Morning Sky

Saturn is visible in the southern predawn skies during February.  At the beginning of the month, Saturn rises in the southeast at 12:30 a.m. and by month’s end it appears at 10:45 p.m.  The bright star Spica appears about 18 degrees to the right of Saturn.

Early in the month, the moon passes Spica and Saturn.  On the morning of February 2, the moon is 5 degrees to the lower left of Spica and 12 degrees to the lower right of Saturn.  On February 3, the moon is 4.5 degrees below Saturn as shown on the above chart.

Venus rapidly moves into the sun’s bright glare during the month to reappear in the evening sky in the spring, closing out its morning apparition for 2012-2013.

If we could see the solar system from above, we could see its distribution of planets around the sun.  (Click the image to see it larger.) Venus is moving behind the sun as seen from Earth.  Mercury and Venus appear together in the evening sky.

Take a look at the February sky!