SKY HAPPENINGS

The Sky for November 2011
By Faylene Roth

NOTE: Mountain Standard Time replaces Daylight Saving Time on Sunday, November 6.
At 2:00am clocks are set back to 1:00am.

DAYLENGTH
The length of daylight decreases this month by 52 minutes. Note the progression of earlier sunsets slows significantly during the last week of the month. A sunset time of 4:58pm beats the earliest sunset of next month’s winter solstice period by just one minute. This time lag occurs when the earth’s orbit begins to round the near end of its elliptical curve. As a result, its southern drift through the sky diminishes and its orbital path seems to parallel the east to west motion of the sun across the sky from sunrise to sunset. The sun would continue to set earlier until the solstice if its orbit were circular. However, the increase in the earth’s speed as it approaches perihelion (point closest to the sun in its elliptical orbit) delays the time of the next sunset which offsets the earlier sunsets that would otherwise occur.

MOON HAPPENINGS
Nov. 2 – First Quarter Moon sets soon after midnight.
Nov. 10 – Full Moon occurs at 1:16pm and rises at 5:00pm.
Nov. 18 – Last Quarter Moon rises shortly before midnight.
Nov. 24 – New Moon occurs at 11:10pm.
(The time of moonrise and moonset assumes a flat horizon. Actual time may vary.)

METEOR EVENTS
A waxing, then waning moon washes out the Taurid Meteor Shower this year. The Taurids produce two peaks—one on November 5 and one on November 12. While it is not a prolific meteor event, it does produce occasional fireballs, so be on the alert for them for several weeks either side of the peaks.
On the night of November 17/18 look eastward right before midnight for signs of the Leonid Meteor Shower. Although best viewing for all meteor showers is after midnight, a last quarter moon breaks over the horizon about 11:30pm. The Leonids can produce about 40 meteors per hour, so some of the brightest will still be visible.

WHAT STARLIGHT REVEALS
When astronomers pass starlight through a spectrometer, they can identify the elements in that star. The spectrometer separates light into a spectrum, just like a prism does. Each element produces a unique spectral pattern with dark absorption lines at specific wavelengths. The pattern of absorption lines serves as a fingerprint for each element. Most stars contain about 90% hydrogen and 10% helium with trace amounts of heavier elements. Hydrogen and helium were formed in the first few minutes after the Big Bang and later formed the first stars. Main-sequence stars, like the sun, continue to produce helium through nuclear fusion of hydrogen. Stars with greater mass than the sun are hot enough to fuse helium nuclei into carbon and some produce even heavier elements; such as, oxygen, neon, magnesium, silicon, sulfur, argon, calcium, titanium, chromium, and iron. Metals heavier than iron are produced when massive stars collapse in supernova explosions. Elements produced from these massive star explosions become part of the interstellar dust which may later condense into gas clouds that form new stars and planets. Supernovae, along with radioactive decay, are the source of the elements found on Earth.

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.

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.

VISIBLE PLANETS

Jupiter - At the first of the month, Jupiter will be visible in the morning sky, low on the western horizon. Soon it sets before dawn and becomes the dominant feature in the evening sky. Look for it in Pisces below the Great Square of Pegasus. Jupiter just passed opposition in October, so it is still shining at its maximum magnitude. (Magnitude -2.9)

Mars - Watch Mars as it continues to brighten over the next few months. Its intense red orb stands out overhead in the morning sky. Find it at Leo’s chest and follow it nightly as it moves eastward below Regulus (Leo). (Magnitude +1)

Mercury - It’s never easy to see Mercury, but worth the effort. This month, if you find Venus, then Mercury is a little below and to the right. It follows Venus through Scorpius, then Ophiucus. Look for it about one-half hour after sunset. Binoculars will be helpful. (Magnitude -0 to +1.5)

Saturn - Another morning highlight joins Jupiter on November 1. Saturn rises in the eastern sky at dawn, then gradually appears a few minutes earlier each day. It has returned to view from its orbit to the far side of the sun. Its brilliant yellow light shines brighter than when it was last visible, because its rings are now tilted favorably towards us. (Magnitude +0.7)

Venus - Look for Venus to reappear in the evening sky this month as it exits from its transit across the sun. Any sighting will be within one-half to one hour after sunset. Since Venus is an interior planet, it passes through phases like our moon. Binoculars reveal it to be in its gibbous phase. The planet moves rapidly across the sky, quickly passing through both Scorpius and Ophiucus this month. On November 9 it appears low in the WSW sky about four degrees above red-tinged Antares (Scorpius) with Mercury in between. (Magnitude -3.9)


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.

In autumn and winter the visible part of the Milky Way stretches from west to east towards the outer reaches of the galaxy. Follow it from Cygnus through Cassiopeia, Perseus, Auriga, continuing between Gemini and Orion and on to the far edges of the galaxy.

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.