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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 2011
By Faylene Roth

 

May sunrise
and sunset times


DATE

SUNRISE

SUNSET

1

6:21am

8:10pm

2

6:20am

8:11pm

3

6:19am

8:12pm

4

6:18am

8:13pm

5

6:17am

8:14pm

6

6:16am

8:15pm

7

6:14am

8:16pm

8

6:13am

8:17pm

9

6:12am

8:17pm

10

6:11am

8:18pm

11

6:10am

8:19pm

12

6:09am

8:20pm

13

6:08am

8:21pm

14

6:08am

8:22pm

15

6:07am

8:23pm

16

6:06am

8:24pm

17

6:05am

8:25pm

18

6:04am

8:26pm

19

6:03am

8:26pm

20

6:03am

8:27pm

21

6:02am

8:28pm

22

6:01am

8:29pm

23

6:01am

8:30pm

24

6:00am

8:31pm

25

5:59am

8:31pm

26

5:59am

8:32pm

27

5:58am

8:33pm

28

5:58am

8:34pm

29

5:57pm

8:34pm

30

5:57pm

8:35pm

31

5:56am

8:36pm

DAYLENGTH
Earth begins to round the corner at the far end of its orbit this month as it approaches its solstice position on June 21. Its northern hemisphere swings into a more direct face-off with the sun which delivers more intense heat to local canyon walls. The time from sunrise to sunset on May 31 is 14 hours, 40 minutes—only 12 minutes shorter than the June solstice’s longest day. Another effect of the approaching solstice is the increase in the length of twilight from one and one-half hours to two hours during the summer, both before sunrise and after sunset. As the sun appears higher in the sky, its rays of light reach farther around the earth since the diameter of the earth decreases at higher latitudes. Result: the long, warm, lingering evenings of summer. (The time of sunrise and sunset assumes a flat horizon. Actual time may vary depending upon the landscape.

MOON HAPPENINGS
May 3 - New Moon occurs at 12:51am.
May 10 - First Quarter Moon sets soon after midnight.
May 17 - Full Moon occurs at 5:09am, sets at 5:59am, rises again at 9:11pm.
May 24 - Last Quarter Moon rises after midnight.
(The time of moonrise and moonset assumes a flat horizon. Actual time may vary.)

METEOR EVENTS
The Eta Aquarids Meteor Shower offers good viewing May 4-7, just after a new moon. The radiant for this meteor shower is the constellation Aquarius. Aquarius rises in the southeastern sky after midnight when the Milky Way is directly overhead. Expect up to 10 fast-moving meteors per hour once the radiant is overhead.

NORTH GALACTIC POLE
Follow the arc of the handle of the Big Dipper to Arcturus (Bootes), then continue the curve low towards the south to Spica (Virgo). Above the intense blue light of Spica look for the golden brilliance of Saturn. Return to Arcturus then look upward for the faint constellation Coma Berenices which hovers between the Big Dipper and Leo. Coma Berenices is defined by three faint stars that form two lines perpendicular to one another. Look into this space and you are gazing out through the top of our Milky Way Galaxy. Few stars are visible in this region because star density is less as you look outward towards the edge of the galaxy, a mere 3,000 light years from Earth’s position. Beyond the Milky Way, though, are thousands of other galaxies which have been revealed by the world’s largest telescopes.

TELESCOPE WORKSHOP
Red Rock Astronomers hosts a telescope workshop this month. If you are a telescope owner who wants to share your experiences, or a telescope owner who wants to learn to use your telescope, or you want to learn how to buy a telescope, then this workshop is for you. Join Alex at Old City Park on Sunday, May 29, at 8:00pm. Meet at the southwest corner of the park below the bandstand. This event is sponsored by WabiSabi and is free and open to all ages. If weather cancels,call
210-0066 for reschedule information.


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.

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.


VISIBLE PLANETS
Jupiter - Four planets dot the eastern sky in morning twilight this month. On May 1 (and again on May 29) a thin, waning, crescent moon joins them just above Jupiter. The second brightest of the planets is Jupiter. It maintains its fixed position near the fork of the angle in Pisces while the other three planets visibly move eastward in a tightening cluster each morning. Jupiter is the last of the planets to rise on May 1, but by mid-month the other planets are lagging behind it. On May 11, Jupiter and Venus are within one-half degree of one another. By the end of the month, Jupiter has separated itself from the cluster of the others and appears farther west. (Magnitude -2.2)

Mars - The faintest of the four planets in the morning sky is Mars. On May 1 it rises one minute ahead of Jupiter. By May 7 it lags behind Jupiter by about six minutes. All four planets rise earlier each morning. Relative to one another, however, their positions change. Mars continues to outpace Mercury and Venus and is rising about one-half hour after Jupiter by the end of the month. Its reddish glow may be difficult to detect in the brightening sky. On May 23 Mars is one degree from Venus to its lower right. (Magnitude +1.3)

Mercury - The best opportunity to view Mercury is early in the month when it rises soon after Venus and before Mars and Jupiter. On May 7 it rises only one minute ahead of Jupiter. The next day it appears less than 1.5 degrees from Venus. On May 11, Mercury, Jupiter, and Venus are within 2.1 degrees. Mercury then lags behind first Jupiter then Mars. On May 21, Mercury, Mars, and Venus are within 2.1 degrees. Even though it brightens throughout the month, Mercury soon becomes obscured by the glare of the rising sun. (Magnitude 0)

Saturn - Saturn is the sole planet of the night sky this month. Its golden orb joins bright stars Arcturus (Bootes), Regulus (Leo), and Spica (Virgo) high in the eastern sky each evening. (Magnitude +0.5)

Venus - At the beginning of the month Venus rises ahead of the other three visible planets. It is by far the brightest of the morning planet cluster. Towards midmonth Venus lags behind, first Jupiter, then Mars. (Magnitude -3.9)


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.

MAJOR CONSTELLATIONS this MONTH

Overhead
Bootes
Leo

Northward
Cassiopeia
Cepheus
Draco
Ursa Major
Ursa Minor

Eastward
Corona Borealis
Hercules
Lyra

Southward
Corvus
Crater
Hydra
Virgo

Westward
Auriga
Cancer
Canis Major
Canis Minor
Gemini
Orion

Follow the arc of the Big Dipper’s handle eastward to Arcturus, springtime’s brightest star (Bootes). Continue the arc towards the horizon to Spica (Virgo). A loop upward and back to the handle passes through Regulus (Leo).

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.

Moab sky chart April 2011

 
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