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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 2012
By Faylene Roth



DAYLENGTH

The period of daylight decreases rapidly this month. We lose 72 minutes by month’s end. Civil twilight begins after sunset and provides adequate light for most activities for an additional one-half hour. Nautical twilight continues another 30 minutes with colors and shapes fading from the landscape. Astronomical twilight darkens the horizon over the final half hour of twilight. The reverse progression applies to dawn.

DATE

SUNRISE

SUNSET

1

7:15am

7:00pm

2

7:15am

6:59pm

3

7:16am

6:57pm

4

7:17am

6:55pm

5

7:18am

6:54pm

6

7:19am

6:52pm

7

7:20am

6:51pm

8

7:21am

6:49pm

9

7:22am

6:48pm

10

7:23am

6:46pm

11

7:24am

6:45pm

12

7:25am

6:44pm

13

7:26am

6:42pm

14

7:27am

6:41pm

15

7:28am

6:39pm

16

7:29am

6:38pm

17

7:30am

6:36pm

18

7:31am

6:35pm

19

7:32am

6:34pm

20

7:33am

6:32pm

21

7:34am

6:31pm

22

7:35am

6:30pm

23

7:36am

6:28pm

24

7:37am

6:27pm

25

7:38am

6:26pm

26

7:39am

6:25pm

27

7:40am

6:23pm

28

7:41am

6:22pm

29

7:42am

6:21pm

30

7:43am

6:20pm

31

7:44am

6:19pm

MOON HAPPENINGS
Oct 9 – Last Quarter Moon rises in the early am hours.
Oct 15 – New Moon occurs at 6:02pm.
Oct 22 – First Quarter Moon sets in the early am hours.
Oct 30 – Full Moon occurs at 1:49am and rises October 29 at 7:15pm.
(The time of moonrise and moonset assumes a flat horizon. Actual time may vary.)

WINDOW TO THE UNIVERSE
Autumn skies direct our view, not towards the center of our galaxy as in summer, or the outer boundary of our galaxy as in winter but in a perpendicular direction out of our galaxy. The Milky Way Galaxy is only a few thousand light years thick at the point where our sun is located. The number of stars above and below our position does not rival the dense populous regions we see in winter and summer when looking through the plane of the galaxy. The direction of our view depends upon the season of the year and explains why autumn skies and spring skies are less populated with stars. What is visible, though, with large telescopes is out of this world. When large astronomical telescopes are directed through the Great Square of the constellation Pegasus, they provide a look beyond our galaxy and into the surrounding universe. Stargazers may view, with the naked eye, four to twelve stars that are within our galaxy. Binoculars reveal several hundred stars. In fact, hundreds of thousands of stars are visible in almost any direction with enough telescopic magnification. But, beyond the margins of our galaxy—at about 2000 light years—numerous neighboring galaxies come into view. They range from tens of millions to hundreds of millions of light years from us. And, beyond them, quasars (perhaps representations of galaxies in their early phases of formation) lie billions of light years away.

METEOR EVENTS
Around October 7 look for slow-moving meteors with long trains from the Piscid Meteor Showers. Best viewing is around midnight when faint Pisces is overhead. The circumpolar Draconid Meteor Showers occur October 7-10. Look for these meteors emanating from the low northern horizon around 2am. On October 11 scan the area around Taurus once it moves into its overhead position after 2am. The early dawn hours of October 14/15 offer some of the fastest-moving meteors of the year as the Geminid Meteor Showers pass overhead in the pre-dawn hours. The most promising meteor shower of the month is the Orionids spanning October 20-24 with some meteors visible a few days before and after. Best viewing is after midnight when the waxing moon has set and into the early morning hours.

Note: Hold your hand at arm’s length to measure apparent distances in the sky. 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 fist with the thumb extended at a right angle equals 15 degrees. The hand stretched from thumb to little finger approximates 20-25 degrees. The diameter of both the full moon and the sun spans only 0.5 degree. Adjust for the size of your hand.

VISIBLE PLANETS
Jupiter – Our largest planet rises before midnight about 23 degrees north of due east. Look for it between the extended horns of Taurus. By morning twilight it shines overhead. On October 4 Jupiter rises with a celestial cluster that includes the waning gibbous moon, the Pleiades star cluster, and aging red star Aldebaran (Taurus). The same cluster reoccurs October 31. (Magnitude -2.6)

Mars – The red planet sets early in the SW skies about 23 degrees south of due west.. It progresses towards the head of Scorpius, both of which set earlier each evening. A final treat soon after sunset on the evening of October 18 reveals red-lit Mars about four degrees north of aging red star—Antares (Scorpius)—with a waxing crescent moon to the east. Mars disappears into the sun’s glare within a few days. (Magnitude +1.2)

Venus – Our most brilliant planet rises about three hours before the sun throughout October. Its companion this month is blue-tinged Regulus, a 1st magnitude star in Leo. They appear less than one degree apart on the morning of October 3. On October 12 Venus appears about six degrees north of a thin waning crescent moon. (Magnitude -4.1)

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; Your Sky at http://www.fourmilab.ch/yoursky/
To find out when the space shuttle and International Space Station are visible from your location, go to: http://spaceflight.nasa.gov/realdata/sightings/index.html and click on Sighting Opportunities.

MAJOR CONSTELLATIONS this MONTH

Overhead

Aquila
Cygnus
Delphinus
Lyra
Pegasus

Northward

Cassiopeia
Cepheus
Draco
Ursa Minor

Eastward

Andromeda
Aries
Auriga
Perseus
Pisces
Taurus

Southward

Aquarius
Capricornus
Cetus
Sagittarius
Scorpius

Westward

Corona Borealis
Hercules
Ophiucus

Overhead the Summer Triangle relinquishes its position to the fall constellations centered around the Great Square of Pegasus. In the eastern skies the winter constellations of Taurus and Orion appear before midnight. Ursa Major (aka Big Dipper, Plow, Wagon, Big Bear) dips so low in the northern sky that it can be difficult to see without a clear view of the horizon.


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 sky from astronomical twilight to midnight. As the night and month progresses, the constellations shift toward the northwest. The celestial equator is measured in hours (h).
The ecliptic is measured in degrees.

sky chart October 2012
 
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