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Moab UT (at City Hall)
38O34’ N Latitude 109O33’ W Longitude
4048 ft - 1234 m

The Sky for February 2010

By Faylene Roth

Sunrise and Sunset Times for

The period of daylight lengthens by 61 minutes this month. Civil twilight continues to provide sufficient light for outdoor activities for a half hour after sunset. When the sun has dropped six degrees below the horizon nautical twilight begins. During the next half hour, color and detail fade from the landscape. Astronomical twilight begins when the sun reaches twelve degrees below the horizon. In about one-half hour, when the sun sinks to eighteen degrees below the horizon, the sky fades to black. (The time of sunrise and sunset assumes a flat horizon. Actual time may vary depending upon the landscape.)

February begins with a waning gibbous moon rising soon after 9:00pm above and to the right of Saturn. On February 2 it rises after 10:00pm below Saturn. On February 3 Spica (Virgo) sits to the upper left of the moon. The last quarter moon occurs February 5. On February 7 a waning crescent moon rises about 3:00am with Antares (Scorpius). By morning twilight they will be about two degrees apart. The new moon at 7:51pm on February 13 is the second new moon after the summer solstice which marks the beginning of Chinese New Year . (China’s time zone is 15 hours ahead of Moab, so the new year is celebrated on February 14.) February 14-17 a waxing crescent moon is on its back with the horns pointing upward. On February 21 the first quarter moon rises between the Pleiades and Aldebaran (Taurus). On February 25 the moon appears high in the night sky with Mars to the left and Castor and Pollux (twin stars of Gemini) above. Two days later the moon rises an hour before sunset below Regulus (Leo). On February 28 a full moon rises a few minutes before the sun sets. (The time of moonrise and moonset assumes a flat horizon. Actual time may vary depending upon the landscape.)

Vesta is the second largest asteroid orbiting between Mars and Jupiter in the asteroid belt. Look for it with binoculars or a small telescope February 17-19 in Leo. It could be barely visible with the unaided eye, shining at +6.1 magnitude. First find the head of Leo the Lion which forms a backward question mark (or scythe). Regulus is Leo’s brightest star and sits at the base of the question mark. Above and to the left look for the next brightest star. It is Algieba, a 2nd magnitude star. On February 17, Vesta appears to the left of Algieba. On February 18, it will be in the same field of view as Algieba through binoculars. On February 19, Vesta has moved to the right of Algieba.

The Aurgid Meteor Shower spans the first three weeks of February. Occasional brilliant fireballs are more likely to occur than numerous meteor streaks.

The space shuttle Endeavor is scheduled to launch on February 7. To find out when the space shuttle and International Space Station are visible from your location, go to the following website and click on Sighting Opportunities:

Note: Hold your hand at arm’s length to measure apparent distances in the sky. Adjust for the size of your hand. The width of the little finger approximates 1.5 degrees. Middle, ring, and little finger touching represent about 5 degrees. The width of a fist is about 10 degrees. The hand stretched from thumb to little finger equals 20 degrees. The diameter of both the full moon and the sun spans only 0.5 degree.

Jupiter - As Jupiter sinks lower on the western horizon each night, it relinquishes its dominance of the evening sky to Venus which is climbing higher above the horizon each evening. At the beginning of the month Jupiter appears six degrees above Venus. On the evening of February 16 the distance has decreased to one-half degree. After February 17 Jupiter sets before Venus and soon disappears into the glare of the sun. Jupiter reaches conjunction with the sun on February 28. On that date its orbital position will be on the far side of the sun from Earth. In Aquarius. (Magnitude -2.0)

Mars - Look for the red-orange orb of Mars in the eastern sky at dusk. At the beginning of the month, it is east of Leo about three degrees above the Beehive Cluster in the center of Cancer. It will shine as brightly as the sky’s brightest star, Sirius, far to the south. Mars continues its retrograde motion throughout February. By month’s end it has moved westward towards Gemini and will be fairly high in the sky as twilight ends. Mars dims significantly over the next few months. It will slightly outshine Pollux (Gemini) this month. In early morning twilight look for Mars low in the northwestern sky. (Magnitude -1.1 to -0.6)

Mercury - One-half hour before sunrise on the mornings of February 11and 12 provides an opportunity to view Mercury. A high vantage point and a clear view of the southeastern horizon is essential. First find the thin crescent moon. On February 11 look for Mercury to the left of the moon. On February 12 look below and to the right. Mercury will be less than five degrees from the moon. If not visible, use binoculars. Place the moon in the upper left field and look for Mercury in the lower right field. Mercury then travels into the glare of the sun and disappears from view. (Magnitude -0.1)

- Once Leo has filled the eastern sky, Saturn will soon rise due east on the celestial equator. Look for it after 10:00pm at the beginning of February. By month’s end it is rising earlier but not until astronomical twilight has fully faded from the sky. Saturn remains high in the southwestern sky at morning twilight. It is in retrograde motion this month, drifting westward in the sky. Look for it between Spica (Virgo) and Denebola (Leo’s tail). Its position will not change much during the month. In Virgo. (Magnitude +0.5)

Venus - A high vantage point and clear view of the west-southwestern horizon reveals the return of Venus to the evening skies. On February 1 it appears three degrees above the horizon at sunset. Jupiter appears six degrees above. Venus gains altitude throughout the month, reaching six degrees above the horizon by month’s end. On the evening of February 16 look for Venus and Jupiter just after sunset. The two planets will be within one-half degree of one another—Venus in the lower position. Venus then reclaims its dominance as the “evening star.” It lingers in the evening sky as Jupiter sinks below the horizon. In Pisces. (Magnitude -4)

Daytime Phenomenon - The sun travels across the daytime sky with a retinue of planets this month. While it won’t be visible, it is interesting to imagine. Uranus, Venus, and Jupiter flank the sun on its left. Neptune and Mercury flank the right. Pluto is farther west. On February 25 all the planets but Pluto are clustered very close to the sun.

Note: Apparent magnitude values range from -4 to +6 for most planets and visible stars. The lower the value the brighter the object. A decrease of 1.0 magnitude is 2.5 times brighter.

Primary Sources: USGS, U.S. Naval Observatory,


Canis Minor

Ursa Major
Ursa Minor


Canis Major


Locate the Beehive Cluster (aka Praesepe) with the unaided eye about three degrees below Mars at the beginning of the month. This open cluster of nearly 200 stars that formed one to two billion years ago is near the center of Cancer.

Hold the star chart high above your head and match the compass directions to the direction you are facing.
Adjust the star chart by orienting Ursa Major (Big Dipper) to match its position in the sky.

The star chart approximates the night sky from astronomical twilight to midnight. As the night and the month progress, the constellations will shift toward the northwest.

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