NIGHT SKY HAPPENINGS

The Sky for November 2017
By Faylene Roth

Stargazers will welcome dark skies as early as 6:00 P.M. once Daylight Saving Time (DST) ends on the morning of Sunday, November 5. Brilliant 1st magnitude stars of summer and winter line both the eastern and western horizons by 7:00pm. These stars are embedded in and near the plane of the Milky Way. But overhead it is the Great Square of Pegasus that claims the mid-autumn night sky. The view is perpendicular to the plane of our galaxy. The Great Square, often called the Window to the Universe, directs our view out of our spiral galaxy into a larger sampling of galaxies, black holes, neutron stars, and a multitude of stars of all sizes—passing, colliding, and exploding. And to think that we are a part of this phantasmagoria! Don’t forget to take in the constellations of Capricornus, Aquarius, Pisces, Aries, Taurus, and Gemini along the Ecliptic. Then peer over the Celestial Equator to view the southernmost visible star from our latitude: 1st magnitude Fomalhaut (Piscis Austrinus) very low on the southern horizon due south of Pegasus.

.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 – Only one planet is visible with the naked eye this month: It is Saturn—low on the SW horizon at twilight between Ophiuchus and Sagittarius. (Magnitude +1.4)
Morning (At Twilight)
Venus – Venus continues to outshine Mars but hovers well below it on the eastern horizon in Virgo. (Magnitude -3.9)
Mars – The red disk of Mars remains visible throughout the month drifting westward towards Spica in Virgo. After DST ends on November 5, Mars will appear higher in the sky at twilight. (Magnitude +1.8)

MOON HAPPENINGS
November 3 – Full moon (12:40pm) rises at 7:18pm.
November 10– Dark evening skies return with the waning last quarter moon rising after midnight.
November 18– New moon (1:12pm) yields dark skies for several nights.
November 26– 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.

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.