SKY HAPPENINGS

The Sky for November 2012
By Faylene Roth

DAYLENGTH
November days shorten and cool as the direct focus of sunlight slides south over the swollen bulge of the earth’s equator. Length of daylight decreases by 51 minutes over the course of the month. If we ignore the switch from from daylight saving time to standard time, then the sun continues to rise later each day—31 minutes in real time during the month. However, the time of sunrise does not reverse until the beginning of January 2013, while later sunsets begin about one week before the winter solstice. In fact, the time of sunset varies by only a few minutes between the end of November and the time of the winter solstice. The imbalance in the contribution of sunrises and sunsets in determining the period of daylight results from the interplay of the earth’s rotation, revolution around the sun, and position in its elliptical orbit.

Dawn and dusk also add to the period of usable daylight. Civil twilight provides adequate light for most activity and extends daylight about one-half hour before/after sunrise. Nautical twilight reveals shapes and fading colors but loses detail and begins approximately one-half hour before/after civil twilight. Astronomical twilight illuminates the sky with a faint glow. It occurs about one-half hour before/after nautical twilight.

MOON HAPPENINGS
Nov 6 – Last Quarter Moon rises around midnight.
Nov 13 – New Moon occurs at 3:08pm.
Nov 20 – First Quarter Moon sets in the early am hours.
Nov 28 – Full Moon occurs at 7:46am and rises at 5:16pm.
(The time of moonrise and moonset assumes a flat horizon. Actual time may vary.)

METEOR HAPPENINGS
Two minor meteor events during the first half of November deserve mention because they promise peak activity well before midnight, which is unusual for meteor showers. The Southern Taurid Meteor Shower peaks at 10:00pm on November 4. The Northern Taurids peak at 9:00pm on November 11. The radiant for both events is the constellation Taurus, easily located by the presence of Jupiter. A waning gibbous moon rising in the eastern sky may reduce the visual impact of the Southern Taurids, but the Northern Taurids can expect better viewing conditions since they peak as the moon approaches new phase.
The major meteor shower this month—the Leonids—occurs November 13-20. Expect peak activity of 20 meteors per hour around 1:00am on the night of November 17/18. Its radiant, the constellation Leo, rises about one and one-half hours after Gemini. Viewing conditions should be good since the nearly full moon sets several hours before midnight.

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.

VISIBLE PLANETS
Jupiter – The dominant planet of the night sky continues to appear in Taurus near its 1st magnitude red star Aldebaran. Jupiter remains in the sky throughout the night, so look for it in the western sky during morning twilight. On November 1 it appears within three degrees of the moon as they rise around 8:30pm (depending on surrounding landscape).
On November 28, the planet again pairs up with the moon. By the end of the month, Jupiter rises as the sun sets. (Magnitude -2.8)

Mars – The red planet can still be viewed in the evening twilight low on the western horizon in Sagittarius. On the evening of November 16 look for it below a waxing crescent moon. (Magnitude +1.2)

Mercury – At month’s end look for Mercury below Venus and Saturn in the early morning twilight in Libra. (Magnitude +1.9)

Saturn – The ringed planet joins Venus in Virgo this month. It becomes easier to see in the morning twilight on the eastern border of Virgo—below Venus—as the month progresses. The two planets are less than one degree apart on the mornings of November 26-27. (Magnitude +0.6)

Venus – Our nearest planet appears in the morning twilight near Virgo’s bright star Spica at the beginning of the month. It rises with a thin waning crescent moon on the morning of November 11. During the month it moves eastward across Virgo approaching within one degree of Saturn on November 26 and then moving into Libra. (Magnitude -4.0)

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.

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.

Mid-autumn skies feature the Great Square of Pegasus overhead with the constellation Andromeda dangling from its northeast corner. The Andromeda Galaxy appears as a naked-eye fuzzy area about five degrees northwest on a line perpendicular to the center point of the constellation Andromeda. The lone 1st magnitude star in the southern sky is Fomalhaut (“mouth of the fish”), part of a southern hemisphere constellation call Pisces Austrinus (“southern fish”).

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.