What's Up in the Night Sky?

October 2021 - Vol. 25, No. 10

Astra's Star Gate

This Month's Night Sky - NOTE: The next paragraph describes the sky as it appears at 10 pm EST (11 pm EDT) near mid- month. The sky also looks this way at 11 pm EST (midnight EDT) during the beginning of the month and at 9 pm EST (10 pm EDT) by month's end.

Although the Summer Triangle is still visible in the W, the Square of Pegasus is now prominent high in the S. Far below, lonely Fomalhaut [FOE-muh-lowt] of Piscis Austrinus glitters near the S horizon. Between Pegasus and the N pole star, Polaris (Ursa Minor), find the familiar "W" shaped asterism of Cassiopeia. If you are fortunate to be viewing from a dark site, you will also see the constellations, Perseus and Auriga, with its bright star, Capella, embedded in a starry band stretching across the night sky from E to W. You are looking at the Milky Way, one of the spiral arms of our galaxy. In the E the constellations, Gemini, with its bright twin stars, Castor and Pollux, and Orion, with its distinctive hour glass asterism, rise above the E horizon. Now the Big Dipper (Ursa Major) dips low in the N.

MERCURY is too close to be seen as the month opens, but appears in the second half of the month, giving the northern observers the best morning circumstance for spotting the innermost planet. VENUS favors the southern hemisphere in the evening sky andwill be in conjunction with the first magnitude star Antares on the 16th. MARS cannot be seen as it is in conjunction with the Sun on the 18th. JUPITER resumes prograde motion this month, after stalling in Capricornus on October 18. SATURN also returns to prograde motion mid-month, still passing through the stars of Capricornus. The gas giants still dominate the southern horizon and are visible most of the night. A detailed chart is presented below. URANUS is out most of the night for observers with telescopes. NEPTUNE is also observable most of the night in Aquarius.

Review how to determine Angular Measurement.

Calendar of Events

NOTE: For those observers not in the ET zone, convert the calendar times to your zone's time by subtracting one hour for CT, two for MT and three for PT. Don't forget to adjust for Daylight Savings Time when necessary by subtracting one hour from your planisphere's time. Dawn and dusk times must also be corrected. See your local newspaper, TV news, or cable TV's Weather Channel for sunrise and sunset times or check with the U.S. Naval observatory. Unfortunately some of these events may occur during daylight hours in your area.

03 Venus at aphelion.
04 The Zodiacal Light or "false dawn" is visible in the E about 2 hours before sunrise. This pyramidal glow is caused by meteoroids, dust particles spawned by passing comets, etc., that have settled into the ecliptic plane (path followed by the Sun, Moon and planets), reflecting the Sun’s light before it rises here. This phenomenon will be visible for the next two weeks.
08 Draconids originate in the northern sky, so this is a northern shower best seen in the evening sky when the radiant is at its highest. The hourly rate is low but on rare occasions an outburst may occur.
Moon at perigee.
Mars in conjunction with the Sun.
09 Venus 3 deg. S. of Moon.
Mercury at inferior conjunction.
11 Saturn stationary, see monthly topic below.
14 Saturn 4 deg. N. of Moon.
15 Mercury at ascending node.
Jupiter 4 deg. N. of Moon.
16 Venus 1.5 deg. N. of Antares.
18 This night Mercury will be at perihelion and also reach a stationary point (1 UT) in Earth's sky.
Jupiter stationary, see monthly topic below.
21 Orionids meteor shower peak. This shower produces up to 20 meteors per hour. Meteors in this shower are generated by Halley's comet. The orbit of this periodic comet leaves a trail of dust particles on its way to the Sun. This trail of particles remains in this area of space until they encounter the Earth's orbit. This produces the annual shower.
Uranus 1.3 deg. N of Moon.
24 Moon at apogee.
25 Venus at greatest heliocentric lat. S.
Mercury at greatest elongation W. (18 deg.)
26 Moon 1.7 deg. N of M35.
29 Venus at greatest elongation E. (47 deg.)
30 Mercury at greatest heliocentric lat. N.

Lunar Almanac for October 2021

Phases of the Moon Phase and Date(s) Best viewed before local midnight
new moon New
Deep Space Objects
first quarter moon 1st. Qtr
Planets & Moon
full moon Full
last quarter moon Last Qtr
Deep Space & Planets

Topic of the month: Jupiter and Saturn in Capricornus

If you've looked up at the night sky lately, you know those two giant gas planets that met in Earth's sky last year are still hanging out together. Having reached opposition in August this year, the giant planets have been dominating the southern sky if you are in the northern hemisphere. Jupiter is brilliant (-2.8), outshining everything since Venus has been retiring earlier and earlier in the evening. Saturn rises before Jupiter, but only glows at 0.5 magnitude this month.

Jupiter and Saturn stationary points in Capricornus
Jupiter and Saturn at stationary points

The brightest stars of Capricornus are about third magnitude. Jupiter has been near Delta Capricorni aka Deneb Algedi, the 2.85 mag. eclipsing binary star and Gamma Capricorni aka Nashira(not named on diagram,) the 3.65 mag. variable star that can be well seen accompanying the giant planet on a clear, dark night. While the giant planet speds away from the ringed wonder, both appear to stop their motion in Earth's sky as the blue planet overtakes both of them in their orbits. Saturn reaches its stationary point on October 11, then resumes its "normal" prograde motion. Jupiter will be passed a few days later, appearing to Earth-based observers to stand still on October 18. The distance between the two planets will continue to increase for ~10 years when they begin to approach their next Great Conjunction.

These "jewels of the night" have attracted my attention since mid-summer. They share the southern sky with the bright star, Fomalhaut, the southernmost first magnitude star visible to northern-based observers. Fomalhaut is the alpha star of the constellation Piscis Austrinus, that is the southern fish.

Just a note: Last month's almanac topic featured the Mesopotamian constellation Mulapin, formed from stars in Triangulum and Pegasus. These "fall" constellations are prominent for northern observers. If you would like more information on Mulapin the constellation, check out the September issue of What's Up.

--See You Under the Stars!
Astra for Astra's Almanac

This installment of "What's Up?" is ©2021 by Dawn Jenkins for Astra's Stargate. View Ron Leeseburg's Farewell Issue for information on where to find information such as is presented in this almanac.