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

The Sky for May 2009

By Faylene Roth

Sunrise and Sunset Times for
May 2009

The period from sunrise to sunset adds an additional 50 minutes of daylight in May. Civil twilight supplies sufficient light for any outdoor activity for about one-half hour after sunset. Nautical twilight continues another half hour as color and detail fade from view. Darkness overtakes the sky during the next half hour of astronomical twilight . As the ecliptic (sun’s apparent path across the sky) moves northward, astronomical twilight lingers, adding an additional 10-15 minutes of faint background light to the night sky. The reverse progression applies to dawn. Actual times of sunrise and sunset may vary up to 30 minutes or more depending upon the surrounding landscape.

May begins with a first quarter moon high in the western sky on the evening of May 1. On May 2 the moon appears to the right of Regulus. On May 3 it pairs with Saturn. A waxing full moon rises with Spica (Virgo) on May 6. The full moon rises May 8 at 8:21pm. It reaches peak fullness at 10:01pm. By May 15 the moon rises after midnight. The last quarter moon appears in the early morning hours of May 17 with Jupiter. Venus, Mars, and a waning crescent moon form a triangle on the morning of May 21. The new moon occurs May 24. On May 26 a thin waxing crescent moon returns to the evening sky. A first quarter moon returns with Saturn on May 30 in the southwestern sky.

Look east after midnight for signs of the Eta Aquarid Meteor Shower from May 1 to 12. Meteor activity increases May 4-7 and peaks on the night of May 5. Best viewing is between midnight and 4:00am, but a waxing gibbous moon will wash out all but the brightest meteors.

Sunlight reaching your eyes at this moment left the sun’s surface eight minutes ago. Light from tonight’s moon departed its surface 1.5 seconds ago. Light travels two minutes from Venus to reach Earth, 35 minutes from Jupiter, 70 minutes from Saturn. The time it takes light to travel through space is used as a measure of distance. A light year is the distance light travels (at the speed of light) in one year—that is about 5.9 trillion miles. Proxima centauri, our nearest neighbor, is 4.2 light years from Earth. Sirius, the bright dog star trailing Orion, is 8.5 light years away. Arcturus (Bootes) is about 37 light years distant. Starlight from Regulus (Leo) left its surface 77 years ago, during the Great Depression. Light from Spica (Virgo) departed about 260 years ago, a few decades prior to the American Revolution. Light from Polaris began its journey when Shakespeare was a child, about 500 years ago. Look into the center of the Milky Way and see light that has spanned 26,000 years—back to the post-Neanderthal period in Europe. Light from the Andromeda Galaxy left its source 2.2 million years ago. That’s about the time Homo habilis was making a stand in Africa and glaciers capped the La Sal peaks.

Wabisabi is sponsoring an evening of stargazing at Ken’s Lake on Saturday, May 16. Red Rock Astronomers will provide telescope viewing but bring binoculars or a telescope if you have one. Meet in the parking lot at 8:45pm. All ages are welcome. Call 259-4743 for more information. Cloudy skies or incement weather cancels this event.

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 - Watch Jupiter appear in the early morning twilight at the beginning of May. It rises a little earlier each morning as the month progresses. (Magnitude -2.1)

Mars - Look for Mars during the last two weeks of May rising in the ESE sky as the sun rises. Its red-orange disk appears below and south of bright Venus. (Magnitude +1.2)

Mercury - May 1-2 offers a fleeting chance to view Mercury. Find a high vantage point and look low on the WNW horizon about 45 minutes after sunset. Mercury appears about 10 degrees above the horizon between the V-shaped head of Taurus and the Pleiades. Binoculars will increase your chance of seeing the planet in the fading twilight. (Magnitude +1.7)

Saturn - The evening sky features only one planet this month. Look high in the sky below the hind flank of Leo for Saturn’s yellow light. It trails behind Leo’s bright star Regulus. Saturn’s rings reach their maximum tilt of 4 degrees above its equator on May 13. The rings then begin to rotate downward towards an edge-on view. By month’s end Saturn will still be visible from some points in the early morning twilight before it sets in the western sky. (Magnitude +1.1)

Venus - Watch Venus rise about 10 minutes after sunrise in early May. By the end of the month, it rises about 10 minutes earlier than the sun. Venus and Mars move closer together during the last week of May. Look for the crescent moon to form a triangle with the two planets on the morning of May 21. (Magnitude -4.7)

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


Regulus, a 1st magnitude star at Leo’s front flank, dominates the overhead sky. Saturn, at +1 magnitude, trails below the hind flank of Leo. Arcturus, a 0 magnitude star in Bootes, and Spica, a 1st magnitude star in Virgo, highlight the eastern sky.

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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