What's Up in the Night Sky

October 2019 - Vol. 23, No. 10

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 Formalhaut [FOE-ma-lot] of Piscis Austrinus still 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 in the evening sky will be more easily seen from the southern hemisphere. VENUS will rise higher in the evening sky each night, best seen from the southern hemisphere. MARS is close to the Sun but begins to emerge in morning twilight late in the month. JUPITER is low in the evening sky this month, setting well before midnight. SATURN will be visible in the evening sky, also setting before midnight for northern observers. URANUS reaches opposition on Oct 28 and will be above the horizon most of the night. NEPTUNE is visible most of the night in the constellation of 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.

DATE	EVENT
03	Mercury at aphelion. Venus 3 deg N. of Spica. Jupiter 1.9 deg S. of Moon.
05	Saturn 0.3 deg N. of Moon, occultation from Easter Island, southern Africa, southern S. America, and South Georgia.
06	Pluto 0.1 deg N. of Moon, occultation from Australia, Melanesia, southern Micronesia, and western Polynesia. (Need a large scope for this event!!)
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.
10	Moon at apogee. Double moon shadow transit on Jupiter.
13	Double moon shadow transit on Jupiter.
15	Uranus 4 deg N. of Moon.
19	Moon 1.7 deg S. of M-35 star cluster.
20	Mercury greatest elongation E. (25 deg)
22	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, producing the annual shower. Moon 0.7 deg N. of Beehive cluster (M-44).
26	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 until about November 8th as long as the Moon does not interfere. Moon at perigee. Mars 5 deg. S. of Moon.
28	Uranus at opposition.
29	Venus 4 deg. S. of Moon.
30	Mercury 3 deg S. of Venus.
31	Jupiter 1.3 deg. S. of Moon. Mercury stationary.

Lunar Almanac for October 2019

Phases of the Moon	Phase and Date(s)	Best viewed before local midnight
	New 27	Deep Space Objects
	1st. Qtr 05	Planets & Moon
	Full 13	Moon
	Last Qtr 21	Deep Space & Planets

Topic of the month: Andromeda and Perseus

In the northern hemisphere as the summer gives way to autumn, sky watchers remember the story that the constellations enacted in the sky, the story of Andromeda and Perseus. This is due to the prominence of the circumpolar constellations of Cassiopeia (The Lady in the Chair) and Cepheus (The King) as they appear to rise in the eastern sky after the sun sets. The constellations of Andromeda and Perseus follow behind, and are visible in the evening sky on fall nights.

In Greek mythology, Andromeda was the daughter of Cepheus and Cassiopeia, king and queen of Ethiopia. Queen Cassiopeia boasted that Andromeda was more beautiful than the Nereids, nymphs who were followers of the god of the sea, Poseidon. This made Poseidon very angry and to punish the queen for her arrogance, he sent a sea monster named Cetus to ravage the coast of Ethiopia. Because of the suffering of the people, King Cepheus consulted the oracle of Apollo, who told the king that there would be no respite unless he sacrificed his daughter, Andromeda, to the monster. The beautiful Andromeda was chained to a rock on the coast. Fortunately for Andromeda, the hero Perseus spotted her as he was flying past on his magic winged sandals. Perseus was on his way to the island of Seriphos returning his task of slaying the Gorgon, Medusa. Perseus saw the plight of Andromeda, and showed the head of the Gorgon to Cetus, turning the sea monster to stone. He set Andromeda free and the two were married. Like all characters in Greek myths, they lived far from happily ever after.

fall sky image

The prominent stars in this story light up the fall nights. The constellation Cassiopeia is also called the celestial "W" or "M" after the letters they resemble. There is a double star cluster in this modern constellation that is often referred to as the "double cluster." They are visible to the naked eye from dark sites. The Milky Way galaxy is bright in this constellation, the spiral arm extending in Perseus. The bright star Beta Persei is also known as Algol or the "Demon Star", representing the head of the Medusa. This variable star, was the first variable star of its type recognized, called an eclipsing variable. It is really a star system comprised of three stars. The brightest of these, Beta Persi A, is regularly eclipsed by the dimmer component, Beta Persei B, this causes the apparent magnitude of the star to fluctuate from 2.1 - 3.4 every two days. The eerie nature of this star was noted by the Egyptians long ago.

The constellation of Andromeda is best known today for hosting a very large galaxy, called the Andromeda galaxy. Containing over 400 billion stars, this galaxy can be seen by the naked eye from a very dark site. It appears as a large elliptical cloud when observing conditions are right. This galaxy is the largest member of our Local Group of galaxies that includes the Milky Way and another spiral galaxy in the constellation of Triangulum. These are the three major galaxies and a host of other smaller galaxies and star system belong to our Local Group.

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