What's Up in the Night Sky?

October 2020 - Vol. 24, 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-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 begins October at greatest E elongation most favorable for southern observers, then begins fading as it moves toward inferior conjunction on the 25th. VENUS prominent in the morning sky shining brilliantly at -4.1 mag closes on the first magnitude star Regulus for a close conjunction early in the month. MARS dominates the evening sky at -2.6 mag rising high among the stars of Pisces (for northern observers.) The red planet and Earth will be at opposition on the 13th, the closest opposition for the next 15 years. JUPITER is closing the gap between itself and SATURN moving toward the great conjunction. Read about Mars, Jupiter, and Saturn this month in the topic below. URANUS is in the constellation Aries at opposition on the 31st. NEPTUNE past opposition this month is visible most of the night in Aquarius, telescope needed for the two outer gas giants.

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.

01 Mercury at greatest elongation.
This month's full moon is called the "Harvest" Moon. The Harvest moon, is the full moon that occurs closest to the fall equinox, and got its name because it helped farmers work after sunset during the harvest.
03 Venus .09 deg. S. of Regulus.
Mars 0.7 deg. N. of Moon, occultation from South America, W. Antarctica, Ascension Is., SW Africa.
Moon at apogee.
04 Uranus 3 deg. N. of Moon.
06 Mars at closest approach 38.6 million miles or 62.07 million km distant from Earth.
08 Moon 0.02 deg S. of M-35.
Draconid meteor peak (3:00 UT.) Draconids originate in the northern sky, the 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. The moon will rise a couple hours before midnight, but should allow evening observing.
09 Mercury at greatest heliocentric lat. S.
11 Jupiter at eastern quadrature. (Earth and Jupiter make a 90-degree angle with the Sun, Earth is moving away from Jupiter.)
13 Mars at Opposition (23:00 UT) or 7:00pm EDT.
14 Venus 4 deg. S. of Moon.
Mercury stationary.
15 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.
17 Moon at perigee, expect large tides.
18 Saturn at eastern quadrature. (Earth and Saturn make a 90-degree with the Sun, Earth is moving away from Saturn.)
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. The lunar crescent won't interfere with early morning observations.
22 Jupiter 2 deg. N. of Moon.
23 Saturn 3 deg. N. of Moon.
25 Mercury at inferior conjunction.
29 Mars 3 deg. N. of Moon.
30 Moon at apogee.
31 Venus at perihelion.
Uranus 3 deg. N. of Moon.
Uranus at opposition.
The second full moon in a month is called a "Blue Moon". The moon doesn't turn blue but the name sticks as the second moon of the month would disrupt cycle of the seasonal names attached to full moons. (Each season usually contains three full moons, but because of the difference between the solar year and the lunar year, our faithful companion slips in an "extra" full moon periodically.)

Lunar Almanac for October 2020

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
01, 31
last quarter moon Last Qtr
Deep Space & Planets

Topic of the month: Mars Rules: Opposition 2020 / The Great Conjunction

Chart of Mars path through Pisces

The planet Mars roars into October rising in the early evening with a 22.5" disk and 99% illuminated at -2.5 magnitude. Mars appears after Saturn and Jupiter are in the western sky and Venus doesn't rise until 8 hours later. Mars loves to show off when the other bright planets aren't looking. It crosses high in the northern sky, and beams brightly at midnight--finally ruling the night. Although the red planet will never outshine Venus, Jupiter has been bested. At least for a couple of months!

Our closest approach to the red planet occurs on October 6, 2020 when Mars will be 38,568,243 miles or 62,069,571 km away from Earth. Opposition occurs at 23:20 UT on October 13, 2020. Don't miss out on this apparition because Mars will be farther away from Earth for the next opposition on December 8, 2022. For the 2022 opposition, the disk of Mars will be only 17.2” - - smaller than Mars' disk at the beginning of September this year.

Not including planet Earth, no planet ignites my imagination like Mars. Its periodic oppositions always capture my interest and today we know more about Mars than ever thanks to a flotilla of space probes that have orbited and landed on the surface. Unquestionably, the best time to see Mars is when Mars is opposite from the Sun in Earth's sky. Oppositions occur 2 years and 2 months apart in general, that's when amateur astronomers, astrophotographers, and space-faring nations concentrate their attention on Mars.

Mark Schmidt's Mars Image September 23, 2020 - CM 83.3This opposition, Mark Schmidt of Racine County in Wisconsin was kind enough to allow his image to be used on Astra's Stargate. Mark used his 14" Schmidt Cassegrain telescope to take this image on the night of September 23, 2020 at 6:27UT. On this image, an albedo feature on Mars known as Solis Lacus, for "Lake of the Sun" is on the central meridian (CM) of Mars. Astronomers use the CM to designate exactly what part of Mars is visible on the disk. South is up on the image as Mark's instrument has inverted the image. Mars is rotating from right to left in this image, with the left edge preceding and the right edge following. The disk is rotated 25.2 deg. because of the axial tilt of Mars. The southern polar cap has been shrinking as the southern hemisphere has turned toward the Sun. The northern solar cap is at the bottom of the image. This disk of Mars is 97% illuminated.

You won't find Solis Lacus marked on a modern Mars map because it was discovered by the early observers who used telescopes. It was first drawn in 1704 by Jacques Maraldi and named by Giovanni Schiaparelli in 1877. Light and dark features on Mars due to reflected light from the Sun are called "albedo features". Details that can be seen on the planet Mars with Earth-based telescopes only allow the rough features of the planets surface to be resolved. It wasn't until Mars Viking and other space probes visited the red planet that detailed features on Mars could be identified. Solis Lacus is also known as the "Eye of Mars" or the "Black Eye of Mars". Amateur astronomers look for it during oppositions.

Today, surface features making up the Solis Lacus area are Syria Planum, Sinai Planum, Thuamasia Planum and Solis Planum, with other surrounding features as well. Valles Marineris forms the northern boundary and Mark's image shows us why astronomers were so surprised that the "Grand Canyon" of Mars was a giant scar on the surface of Mars. Solis Lacus is perhaps the most changeable feature on the planet. Giant dust storms have been observed to originate in this ares. They may encompass most of the southern hemisphere and have a global impact on the planet. Even dust devils have been observed in Solis Lacus. Most of this area is very dusty. With Valles Marineris in the picture, there is no doubt that this a geologically active area and Syria Planum has been found to contain many small shield volcanoes. Speaking of volcanoes, in the lower right quadrant of Mars in Mark's image, the brightest splotches are volcanoes on Tharis Ridge, including Mount Olympus and my favorite, Alba Patera. They may be hard to see if you are not used to looking at Mars images in small telescopes.Dawn's drawing of Mars September 26, 2020

I always wanted to see the "Black Eye of Mars" in my 6" telescope, but every time I was observing, Solus Lacus was out of sight or covered with dust. This year I was able to see the Solis Lacus area in my telescope and I attempted to make some sketches of it at the telescope. I would like to present this drawing of Solis Lacus, not drawn at the 'scope but actually the next morning. The features popped in and out as I observed but I wanted to present a drawing of Mars as it is seen through a small telescope. The lightly drawn features show how difficult it is to see Mars in a small telescope. This would be how Mars appears in my telescope at about 250x magnification on a fair seeing night--though not great. This year's wild fires in California impacted the viewing of Mars features for many observers. The scan of my paper seems to give Mars a bit of a bluish cast that is not seen through the scope but may be noticed here. For the 2018 opposition, the What's Up almanac featured an article on drawing Mars.

Visually, at the telescope, Mars surface appears a pale orange color. Look at Mars in the sky around opposition and it will probably appear orange to you, even though it is called the "red" planet. In the past, the dark markings on the surface appeared brownish to me but this opposition the dark markings appear grayish - - not brown or black. The northern polar cap (or more likely, the north polar hood) at the bottom of the drawing seemed easier to see when Mars' CM was closer to 30-deg. but I am not sure. Before the Eye of Mars approaches the center of the disk, the right quadrant seems plain compared to the rest of the surface. This part of Mars has been covered with volcanic flows from the huge volcanoes of Tharsis. Amateurs with larger instruments and cameras have spotted clouds on the summit of Olympus Mons. This opposition was a lot more favorable to the northern observers than the closer opposition of 2018 when Mars was low on the horizon.

For more information on oppositions of Mars, check out Astra's Mars Oppositions and the Mars Opposition 2020 pages.

The Great Conjunction

Earth and the outer planets Jupiter and Saturn orbit closer toward their great conjunction when Jupiter overtakes the ringed planet, and the two outer gas giants appear very close together in Earth's sky. This generation's great conjunction occurs on December 21, 2020, the date of Earth's winter solstice when the sun hits the southernmost point in the sky. (The Sun appears to stop or stand above the horizon at the exact same place while Earth's orbit causes it to "turn" and travel toward the north.) We are extremely lucky because this year's conjunction will be seen when Jupiter and Saturn are over the horizon. This was not the case for the 2000 great conjunction. That slipped by without much ado because it couldn't be observed.

Jupiter and Saturn have spent most of 2020 in the eastern side of Sagittarius but last month both planets reached their stationary points and now are continuing in their usual prograde direction. By December 18, both Saturn and Jupiter will have cross into the constellation of Capricornus, and so the actual Earth-based moment of conjunction will occur on the far western edge of that constellation.

What's Up has been focused on the great conjunction this year. The first article in the series was presented in the August 2020 What's Up? issue. The second article appeared in the September 2020 What's Up? issue. Please keep reading the What's Up almanac for more information on the great conjunction. Who knows where we will be for the next one?

Astrologers have long pointed at the great conjunctions of Jupiter and Saturn as bringing plague to Earth and so have associated the 2020 conjunction as a cause or portent of coronavirus. Astra's Stargate is an astronomy site and I only want to state that planetary line-ups are all Earth-based. Jupiter will actually lap Saturn on November 2, 2020 if the solar system is viewed from above, but from Earth's surface this event appears to occur 49 days later. Planets in our solar system, including Earth have stable orbits around the Sun. They resonate with each other because they have each made their orbits together for countless millennium. They are entirely predictable when the cycles they follow are understood--they don't rule human lives.

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

This installment of "What's Up?" is ©2020 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.

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