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SKY HAPPENINGS

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

The Sky for March 2015
By Faylene Roth

 

Sunrise-Sunset
for March

(The time of sunrise and sunset assumes a flat horizon. Actual time may vary depending upon the landscape.)

DATE

SUNRISE

SUNSET

1

6:51am

6:11pm

2

6:49am

6:12pm

3

6:48am

6:13pm

4

6:46am

6:14pm

5

6:45am

6:15pm

6

6:43am

6:16pm

7

6:42am

6:17pm

8

7:40am

7:18pm

9

7:39am

7:19pm

10

7:37am

7:20pm

11

7:36am

7:21pm

12

7:34am

7:22pm

13

7:33am

7:23pm

14

7:31am

7:24pm

15

7:30am

7:25pm

16

7:28am

7:26pm

17

7:27am

7:27pm

18

7:25am

7:28pm

19

7:24am

7:29pm

20

7:22am

7:30pm

21

7:20am

7:31pm

22

7:19am

7:32pm

23

7:17am

7:33pm

24

7:16am

7:34pm

25

7:14am

7:35pm

26

7:13am

7:36pm

27

7:11am

7:37pm

28

7:10am

7:38pm

29

7:08am

7:39pm

30

7:06am

7:40pm

31

7:05am

7:41pm

The densely-studded western sky contrasts with the dearth of stars in the overhead and eastern sky. Earth’s orbit is taking us out of the plane of our galaxy where we have been looking outward through the star-studded Milky Way. As spring approaches our view is directed through the “top” of the galaxy—a mere 1,000 light years populated with fewer stars. The two bright stars on the eastern horizon—0 magnitude Arcturus (Boötes) and 1st magnitude Spica (Virgo) stand out as harbingers of spring.

Twilight extends the period of daylight in three stages at each end of the day. Morning twilight begins with astronomical twilight—about 1-1/2 hours (nearly 2 during summer months) before sunrise—as the eastern horizon brightens. Nautical twilight continues—as the overhead sky turns blue and color returns to the surrounding landscape—for another 30-40 minutes. The final stage—civil twilight—provides adequate light for most outdoor activities for the half hour before the sun crests the horizon. The opposite progression occurs after sunset.

DAYLENGTH
Daylight Time shifts the period of daylight one hour later beginning March 8 at 2:00am. The month of March contributes an additional 78 minutes of daylight—the greatest increase of the year.
Twilight extends the period of daylight in three stages at each end of the day. Morning twilight begins with astronomical twilight as the eastern horizon brightens —about 1-1/2 hours (nearly 2 during summer months) before sunrise when the sun is 18 ̊ below the horizon. Nautical twilight takes over for another 30-40 minutes—as the sun passes 12 ̊ below the horizon and the overhead sky turns blue and color returns to the surrounding landscape—. The final stage—civil twilight—begins when the sun ascends to 6 ̊ below the horizon and provides adequate light for most outdoor activities for the half hour before the sun crests the horizon. The opposite progression occurs after sunset.

CELESTIAL EVENTS
No major meteor showers occur during February, although fireballs—mega-meteors as bright as Jupiter and Venus—often occur. Best chances for viewing are between 3:00am and dawn. Viewing the zodiacal light associated with the spring equinox is more predictable. The best chance to see this cone-shaped beam of light is on moonless evenings between February 7 and 17. Once the golds, reds, and residual glimmers of evening twilight have faded from the western sky, look for a broad beam of white light shooting nearly straight up from the point where the sun had set. The zodiacal light occurs near both equinoxes when sunrise and sunset are nearly vertical to the horizon. It occurs when sunrays from below the horizon reflect off dust particles within the open spaces of our solar system..


MOON HAPPENINGS
March 5 – Full moon (11:05am) rises at 6:31pm. Moonrise occurs about one hour later each night.
March 13 – Dark evening skies until after midnight when the waning last quarter moon rises.
March 20 – Dark sky period for several days before and after the new moon (3:36am).
March 25 – Waxing first quarter moon brightens evening skies until after midnight.
(The moon rises later each day—as little as 30 minutes to as much as one hour. Time of moonrise and moonset may also be delayed in mountainous terrain.)

VERNAL EQUINOX
March 20 marks the first day of spring in the northern hemisphere. The sun rises due east and sets due west. At 4:45pm the ecliptic (sun’s apparent pathway across the sky) crosses the celestial equator (directly above terrestrial equator). The period of daylight and darkness are equally distributed on this day, although the sunrise/sunset table indicates a daylength of 12 hours 08 minutes on March 20. The longer day results from the refraction of light around the curvature of the earth which allows us to see the sun before it crests the morning horizon and after it dips below the western horizon.

ZODIACAL LIGHT
The zodiacal light remains visible in the western night sky throughout March. Look for a beam of white light shooting up from the horizon—due west—after astronomical twilight fades from the night sky. The cone-shaped beam tips slightly northward towards Venus and extends as high as 60 ̊ above the horizon.

MAJOR METEOR EVENTS
No major meteor showers occur in March, but fireballs and scattered meteor activity are not uncommon. Look for slow-moving meteors during the dark sky new moon period from radiants near the circumpolar constellation Camelopardalis (Giraffe) and overhead from Gemini (Twins).

VISIBLE PLANETS

Jupiter -- Jupiter dominates the night sky from dusk until dawn. Look for it high in the sky between Leo and Cancer. It sets as astronomical twilight takes over the morning sky. (Magnitude -2.3)
Mars – Though shining brightly, Mars is lost in the glare of the setting sun. Use binoculars to locate its red disk in early March below Venus before astronomical twilight fades from the night sky. (Magnitude +1. 3)
Saturn – Look for Saturn after midnight as it rises with Scorpius in the southeastern sky. Saturn adds a fourth point of light to the three-star arc of the scorpion’s head. (Magnitude +1.1)
Venus – Venus—now on the far side of the sun—is fully illuminated as seen from Earth. It lingers longer above the western horizon each night after astronomical twilight ends. Venus moves through the faint constellations of Pisces and Aries during the month. On March 22 it pairs with a thin waxing crescent moon at twilight. (Magnitude -4.0)

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
Ursa Minor
Ursa Major
Leo
Cancer
Gemini
Canis Minor
Hydra (head)
Canis Major

Eastward
Boötes
Virgo
Corvus
Crater
Hydra (tail)

Westward
Cassiopeia
Perseus
Auriga
Taurus
Orion


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

Note: Hold your hand at arm’s length to measure apparent distances in the sky. The width of the little finger approximates 1.5̊. Middle, ring, and little finger touching represent about 5̊. The width of a fist is about 10̊. The fist with the thumb extended at a right angle equals 15̊. The hand stretched from thumb to little finger approximates 20̊-25̊. The diameter of both the full moon and the sun spans only 0.5̊. Adjust for the size of your hand.

 
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