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




The Sky for October 2009

By Faylene Roth


Sunrise and Sunset Times for
October 2009

DAYLENGTH
The rapidly shortening days are difficult to ignore this month, especially the earlier sunsets. The period of daylight decreases another 71 minutes during October. Even with an hour and a half of twilight, the skies will be dark before 8:00pm on Halloween night. Saturday, October 31, is the last day of daylight savings time. The official time change occurs Sunday, November 1, at 2:00am when official clocks are turned back one hour. (Actual time of sunrise and sunset may vary depending upon the surrounding landscape.)

MOON HAPPENINGS
October begins with a waxing gibbous moon high in the southern sky at twilight. By October 4 the moon has moved northward in its monthly cycle. The full moon rises at 6:52pm a little north of where the celestial equator intersects the eastern horizon. On October 7 a waning gibbous moon rises after twilight with the Pleiades star cluster. The moon reaches its northernmost position for the month on October 9 when it rises below the twin stars of Gemini. Soon after midnight in the early hours of October 12 look for the moon near Mars in the eastern sky. On October 14 the moon rises due east near Regulus (Leo). In the early morning twilight of October 16 a waning sliver of moon rises just ahead of Venus and Saturn in the eastern sky. Use binoculars to find Mercury about five to six degrees above the horizon. The new moon occurs on October 18. A waxing crescent moon appears within a few days in the evening skies to the southwest. On October 26, after sunset, the first quarter moon appears near Jupiter high in the southern sky, but moving northward again. A nearly full moon will be high in the sky on Halloween night. (Actual time of moonrise may vary depending upon the surrounding landscape.)

METEOR ACTIVITY
Look for minor meteor activity October 6-10 in the vicinity of Draco. The head of Draco the Dragon appears north of Cassiopeia. Its long body arcs over Ursa Minor to the west. Best viewing is right after midnight when Draco is overhead. Major meteor activity occurs October 17-25 during the Orionid Meteor Showers. The Orionids peak on the nights of October 20 and 21. Fifteen to twenty-five meteors per hour are common. Best viewing is before dawn when Orion is overhead.

GREAT WORLDWIDE STAR COUNT
Join with local citizen scientists around the world to gauge the darkness of the night skies. Participants in the Northern Hemisphere count the number of visible stars around the constellation Cygnus the Swan. Observations can be made anytime October 9-23. The GWWSC website provides easy-to-use magnitude charts for estimating the number of stars you see and provides additional information necessary to report local findings. The star count is sponsored by the University Corporation for Atmospheric Research in Boulder, Colorado, to raise awareness of the effect of light pollution on the night sky. Go to their website at http://www.starcount.org/ for directions and a reporting form.

LOCAL STAR COUNT
Join Red Rock Astronomers to participate in our local star count on Friday, October 16. Meet in the southwest corner of Old City Park at 7:45pm for a tour of the night skies followed by the star count. Then learn how to conduct your own star count at other locations in or around or beyond Moab. Telescope viewing provided by Alex Ludwig and Red Rock Astronomers. If you have a telescope to bring to the gathering arrive at 7:00pm to allow time for setup. Call 259-4743 (Faylene Roth) or 259-3313 (WabiSabi) for more information. Sponsored by WabiSabi. All ages are welcome and the event is free.

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.

VISIBLE PLANETS
Jupiter - Look in the eastern region of Capricornus for the lone visible planet of October evenings. Jupiter appears high in the southern sky as twilight fades. It is brighter than any other object in the night sky, excluding the moon. (Magnitude -2.5)

Mars - The red planet rises soon after midnight in the eastern sky, assuming planetary dominance of the night sky as Jupiter sets below the western horizon. Mars begins the month rising below the twin stars of Gemini. Each night it rises a little later and gets a little brighter, moving eastward into Cancer. On October 31 use binoculars to view the Beehive Cluster east of Mars. (Magnitude +0.6)

Mercury - During the first week of October early risers might glimpse Mercury in the early morning twilight below Venus. October 6-8 offers the best opportunity to locate Mercury. Binoculars are suggested. On October 8 Mercury rises within a half degree of Saturn. Mercury relinquishes its place below Venus to Saturn during the next week as it moves closer to the sun. (Magnitude +0.6)

Saturn
- During the second week of October, Saturn overtakes Mercury, gaining center position between Venus and Mercury. On October 10 these three planets form a vertical line up from the horizon. On October 13 Venus and Saturn appear together in the eastern sky a half degree apart. Saturn then overtakes Venus as the first planet to rise in the morning sky. (Magnitude +1.3)


Venus - The dominant light of the morning sky is Venus. On October 6 its brightness provides a guide to Mercury’s location in the sky and on October 13 it showcases Saturn just below it. After the 13th, Saturn will rise before Venus. Look for Venus in the eastern sky about two hours before sunrise. (Magnitude -3.8)

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, http://www.fourmilab.ch/yoursky/

MAJOR CONSTELLATIONS this MONTH

Overhead
Cygnus
Delphinus
Pegasus

Northward
Cassiopeia
Cepheus
Draco
Ursa Major
Ursa Minor


Eastward
Andromeda
Aries
Cetus
Perseus
Pisces
Triangulum

Southward
Aquarius
Capricornus
Ophiucus
Sagittarius
Scorpius


Westward
Aquila
Corona Borealis
Hercules
Lyra
Sagittarius

The Summer Triangle appears in the western sky announcing the end of summer. The Great Square (in Pegasus) dominates the eastern sky as harbinger of the autumn constellations—Andromeda, Aries, Cetus, Perseus, Pisces, and Triangulum.


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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