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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 January 2017
By Faylene Roth

 

Sunrise-Sunset
for January

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

DATE

SUNRISE

SUNSET

1

7:36am

5:08pm

2

7:36am

5:09pm

3

7:36am

5:10pm

4*

7:36am

5:11pm

5

7:36am

5:12pm

6

7:36am

5:13pm

7

7:36am

5:14pm

8

7:36am

5:14pm

9

7:36am

5:15pm

10

7:36am

5:16pm

11

7:35am

5:17pm

12

7:35am

5:18pm

13

7:35am

5:20pm

14

7:35am

5:21pm

15

7:34am

5:22pm

16

7:34am

5:23pm

17

7:33am

5:24pm

18

7:33am

5:25pm

19

7:33am

5:26pm

20

7:32am

5:27pm

21

7:31am

5:28pm

22

7:31am

5:29pm

23

7:30am

5:30pm

24

7:30am

5:32pm

25

7:29am

5:33pm

26

7:28am

5:34pm

27

7:28am

5:35pm

28

7:27am

5:36pm

29

7:26am

5:37pm

30

7:25am

5:38pm

31

7:24am

5:40pm

*Perihelion 7:18am

Star colors stand out on clear cold winter nights. Blue stars (Rigel in Orion) are young hot and supersized, fast and furious fusion reactors burning through hydrogen, producing helium, burning through helium to form carbon, burning through that to create magnesium and oxygen, working its way towards future paroxysms of collapses and inflammatory resurgences as they burn through the heavier atoms—finally stalling out with the collapse of the heavy nuclei of iron atoms—their finale before the final collapse that creates a supernova explosion. A star that has reached the expansion stage of its life cycle as described above emits a red-orange light (Betelgeuse in Orion) because its surface temperature has cooled. If massive enough, it will be a candidate for a future supernova explosion in which the heavier elements found within our galaxy are formed and cast across the universe. Most visible stars, however, emit a white light because they are average size stars like our sun. These stars are likely to shine for billions of years unlike the massive hot blue stars that may burn through their fuel in as little as 200,000 years.

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)

Mars – East of Venus in Aquarius during first few days of month and sets soon after Venus. (Magnitude +1.0)

Venus – During the first three days of January a waxing crescent moon passes first Venus then Mars on the western horizon. Venus reaches its highest point above the western horizon (greatest eastern elongation) on January 12. It is half illuminated like a quarter moon and visible now for several hours after twilight ends. On January 31 the waxing crescent moon sits about 4 ̊ directly left of Venus. (Magnitude -4.4)

Morning (At Twilight)

Jupiter
– Rises around midnight with Virgo and is high overhead by morning twilight. On January 19 look for the moon and Jupiter 2.5 ̊ apart. (Magnitude -1.7)

Mercury – Visible at midmonth when it is near its greatest western elongation. A waning crescent moon is above Mercury on January 25. (Magnitude +0.0)

Saturn – Rises with morning twilight in Ophiucus. Saturn is about 3.5 ̊ west of the waning crescent moon on January 24. (Magnitude +1.4)

MOON HAPPENINGS
January 5 – Waxing first quarter lights the evening sky then sets soon after midnight.
January 12 – Full moon (4:34am) rises at 5:59pm.
January 19 – Dark evening skies return with the waning last quarter moon rising after midnight.
January 27 – New moon (5:07pm) yields dark skies for several nights.

(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
(January)
Range
(January)
Constellation Radiant
Rate
(/hr)
Details
Conditions
Quandrantids

3
1-5
Boots
40

After midnight-
Fireballs possible

Waxing crescent moon sets by midnight during peak
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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