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NIGHT SKY HAPPENINGS

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

The Sky for October 2017
By Faylene Roth

 

Sunrise-Sunset
for October

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

DATE

SUNRISE

SUNSET

1

7:14am

7:00pm

2

7:15am

6:59pm

3

7:16am

6:57pm

4

7:17am

6:56pm

5

7:18am

6:54pm

6

7:19am

6:53pm

7

7:20am

6:51pm

8

7:21am

6:50pm

9

7:22am

6:48pm

10

7:23am

6:47pm

11

7:24am

6:45pm

12

7:25am

6:44pm

13

7:26am

6:42pm

14

7:27am

6:41pm

15

7:28am

6:40pm

16

7:29am

6:38pm

17

7:30am

6:37pm

18

7:31am

6:35pm

19

7:32am

6:34pm

20

7:33am

6:33pm

21

7:34am

6:31pm

22

7:35am

6:30pm

23

7:36am

6:29pm

24

7:37am

6:27pm

25

7:38am

6:26pm

26

7:39am

6:25pm

27

7:40am

6:24pm

28

7:41am

6:22pm

29

7:42am

6:21pm

30

7:43am

6:20pm

31

7:44am

6:19pm

When facing north Ursa Minor (Little Dipper) hangs downward—on the west side—from Polaris (North Star). The crown of Cepheus and chair of Cassiopeia claim dominant overhead positions. Look for the small trapezoidal head of Draco (dragon) in the center of a circle formed by Cepheus, Ursa Minor, Hercules, and Lyra. Its long snaking tail twists towards Cepheus then down and around Ursa Minor finally trailing towards Ursa Major (Big Dipper) which grazes the northern horizon.

Think of the southern October sky as the celestial sea: the small cluster of stars known as Delphinus (dolphin) between Cygnus (swan) and Aquila (eagle), boomerang-shaped Capricornus (sea goat) below, bright Piscis Austrinus (southern fish) far to the south, Aquarius (water-boy) above, Cetus (whale) to the east, and Pisces (fish) above it.

The Great Square of Pegasus (flying horse) hangs overhead, head and neck extending from the southwest corner and legs stretching away from the northwest corner. Andromeda (the constellation) dangles from the northeast corner of the horse’s back. Many of these constellations are linked in an ancient tale that begins when the sea nymphs take offense upon hearing Queen Cassiopeia (Ethiopia) brag about the beauty of her daughter Andromeda. The nymphs complain to the sea monster Cetus (east of Pegasus) who avenges their honor by ravaging the Ethiopian coast. To appease the monster King Cepheus ties Andromeda to a stake on the beach as sacrifice. Alas, Perseus (long arc of stars east of Cassiopeia) flies by on Pegasus and plucks her from her plight—their story now frozen in time.

The secret hidden from this ancient storyteller is Andromeda (the spiral galaxy) alongside the fainter arc of Andromeda (the constellation). On the brighter arc of Andromeda count two stars away from the northeast corner of Pegasus. Make a perpendicular turn northward and count two stars up. The galaxy can be seen as a fuzzy blur with the naked eye.

.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.

VISIBLE PLANETS
Evening (Before Midnight)
Saturn – Look for Saturn on the edge of the Milky Way (in Ophiucus) low on the western horizon. It sets soon after 10pm at the beginning of October and by 9pm at month’s end. (Magnitude +1.4)

Morning (At Twilight)
Venus – Look for Venus in the eastern sky about one hour before astronomical twilight on October 1. It rises a bit later each day. By midmonth Venus becomes lost in the morning glare of twilight. (Magnitude -3.9)
Mars – Look for its red orb on the eastern horizon below Venus as astronomical twilight brightens the sky. By October 5 Mars is rising ahead of Venus and continues to rise earlier each day. By month’s end it rises an hour before astronomical twilight. (Magnitude +1.8)

MOON HAPPENINGS
October 5 – Full moon (12:40pm) rises at 7:18pm.
October 12 – Dark evening skies return with the waning last quarter moon rising after midnight.
October 19 – New moon (1:12pm) yields dark skies for several nights.
October 27 – Waxing first quarter lights the evening sky then sets soon 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.)

Twilight is often the best time to look for Venus and Mercury because they frequently rise or set within one-half to one hour of sunrise or sunset. Twilight transitions between night and day 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. Civil twilight covers the period after sunset during which daytime light quality persists for about one-half hour. Color then fades from the landscape during the 30-40 minute period of nautical twilight during which the overhead sky darkens while the western sky retains color. Astronomical twilight then transitions to night skies that are now darkened along the horizon.

MAJOR METEOR EVENTS
Shower
Peak
(Oct)
Range(Oct)
Constellation
Radiant
Rate
(hr)
Details
Conditions
Orionids
21/22
15-29
Orion
15-20
Bright, fast, long-lasting trains, occasional fireballs
Waxing crescent moon sets 8:04pm

Best time to view any meteor event is between midnight and morning twilight when the radiant is overhead.
Trace the path of any meteor backwards through the sky to reach its radiant--the region of the sky from which meteors appear to originate.

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.

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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