StarWatch: Moravian College Astronomy

OCTOBER 2020

OCTOBER STAR MAP | MOON PHASE CALENDAR | STARWATCH INDEX | NIGHT SKY NOTEBOOK

Print Large Sky Charts For 10 p.m. EDT: NORTH | EAST | SOUTH | WEST | ZENITH

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Current Geomagnetic Field:

lunar phases

1259 OCTOBER 4, 2020: Be a Mars Watcher: If there ever was a planet that humans might migrate and inhabit, concurrent with our present state of technological development, it’s got to be Mars. It has the basic ingredient to sustain human life, water. There is no need to spend billions of dollars transporting the most common molecule in the universe to its surface from Earth. Water is present in a frozen state in the soil, and as a liquid in cavernous expanses beneath its surface. Water, composed of two hydrogen atoms and one oxygen atom, can be dissociated into oxygen to breathe. Hydrogen mixed with oxygen can also power internal combustion engines. Combined with Mars’ carbon dioxide atmosphere, the atoms can be chemically rearranged to produce an abundant supply of rocket fuel. In other words, humans going to Mars can “live off the land,” including the growing of crops, in indoor structures. They do not have to take everything with them. Elon Musk of Space-X wants to die on Mars, and not in a failed attempt to land on the planet or in an accident after establishing residency there. He wants to die of old age on the Red Planet, and at the rate his company is making progress in the entrepreneurial space race, he could very well be on his way, travelling to Mars in the next decade or two to fulfill his dream. Right now, humanity’s next best address to expand its potential for survival is easily visible in the eastern sky, a brazenly bright, pinkish, starlike object rising just after sundown, but better placed higher in the east by 10 p.m. Because of orbital characteristics, Earth and Mars are at their closest distance on October 6 when the two planets will be separated by a mere 38.6 million miles. Seven days later on the 13th, Earth passes directly between Mars and the sun, positioning Mars 180 degrees from Sol. Mars will be at opposition, rising when the sun sets and setting when the sun rises. The full moon does this each month, but for Mars, we have to wait a lengthy 780 days between oppositions. Plus, not all oppositions are favorable. Because Mars circles Sol in a more oval-shaped orbit than the Earth, oppositions can occur when Earth passes Mars near to the Red Planet‘s greatest distance from the sun. The 2012 March 3 opposition saw Mars at a distance of 62 million miles, an aphelion opposition, occurring when Mars was almost at its greatest distance from the sun. Mars was bright, but fainter than the brightest luminary of the nighttime sky, Sirius the Dog Star, which was also visible at the same time. The October 13 opposition occurs near perihelion, meaning that Mars will be near to its closest position to the sun. Mars will appear about four times brighter than it did in 2012, but not as bright as during the year 2003 when the August 28 opposition brought Earth and Mars to within 34.64 million miles, the best positioning in 60,000 years (September 24, 57,617 B.C.). That record won’t hold for much longer, however. Jupiter’s gravity is influencing the Martian orbit, causing it to become more elongated, producing closer perihelion oppositions. The new record will be set on August 29, 2287 when Mars will be 43,244 miles closer to us. For those hearty souls, you can enter that date into your long-term day planners.

1260

OCTOBER 11, 2020: Halley’s Comet: See It Now

While the seven-mile chunk of ice and dust known as Halley’s Comet is approaching the far end of its orbital loop, its nucleus releases a trail of dust each time it rounds the sun and gets heated by its warmth. Over the millennia, its dross has been spread fairly evenly across its track. Twice each year, once in the fall and once in the spring, our planet comes close enough to Halley’s orbit to woo Earth’s inhabitants with a meteor shower. If you’re interested in seeing bits and pieces of Halley scream into the Earth’s atmosphere at 41 miles per second, then put the morning of October 21 on your calendar. That’s when the Orionid meteor shower will be on full display. If weather conditions permit, you’ll be treated from suburbia to approximately 10 meteors per hour radiating outward from above and to the left of the bright, red giant star Betelgeuse, the left shoulder of Orion the Hunter as we view him in the sky. Orion is famous for its three belt stars which are bright, close to each other, and in a straight line. Few Orionid meteors will be seen before midnight because the radiant, the location from which the “shooting stars” appear to be diverging, doesn’t break the horizon until about 11 p.m. Observers, watching deeper into the morning hours of October 21, will witness Orion gaining altitude, with meteors being observed above and below the radiant. Maximum rates should occur before dawn. During the night, Earth rotates into the shower debris like the front windshield of a car plowing through rain. The back windshield hardly gets wet. Similarly, we are on the back window of Earth’s view of the meteor shower until about 1 a.m. EDT which is when our location becomes more of a front window position. Meteor rates should pick up significantly. What gives the Orionids a little extra kick this year is the uptick in hourly rates that occurred between the years 2006 and 2009, and the possible discovery of a periodicity in Orionid meteor rates which is predicted to maximize again between 2020 and 2022. These years are forecast to be above average in Orionid meteor tallies, according to the International Meteor Organization’s calculations. Predicting enhanced rates is always a tricky proposition. Sometimes, the computations come true, like in the famous Leonid storms of the late 1990s and early 2000s, and well, sometimes they don’t. Expect rates to be normal, about 10 meteors per hour, and hope for an outburst that may produce as many as 30 to 50 Orionids per hour, maybe even more. Much success in your quest for Orionids! Ad Astra!

Orionid Meteors radiate from just east of the elbow of the arm of Orion the Hunter which holds his club. Rates of about 20 meteors per hour by dawn from a rural location. This map has been constructed for 2 a.m. using Software Bisque's The Sky. Gary A. Becker graphics...

1261 OCTOBER 18, 2020: Catch a Falling Star This Week: I got into astronomy through meteor observing. At that time, I didn’t have enough money to buy a telescope, so I had to do something to satisfy my desire to look skyward in a more serious fashion. Observing meteors filled that void. I enjoyed it so much that even when my dad and I built my first telescope, grinding and polishing a mirror over an 18-month period, observing meteors was still the chief priority of my observing program. It was a great introduction to astronomy and the night sky. I had to know the constellations, the brightnesses of the stars which they contained, the angular distance that the meteors had traveled, and be able to estimate small intervals of time because the meteor phenomenon was often quick, as short as 1/10th of a second. This week on the morning of October 21, the Orionid meteor shower is on full display. These specks of space dust lost from the famed Halley’s Comet in its innumerable trips around the sun, radiate from a region of the sky located near the elbow of the left arm of Orion the Hunter, above the reddish, supergiant star Betelgeuse, the left shoulder of the Hunter as we see him in the sky. The reason why they diverge from a vanishing point is because the meteoroids, the name given to the particles when out in space, are all traveling parallel to each other as they orbit the sun. The condition is analogous to standing on a long, straight section of railroad tracks. The parallel rails diverge from a distant vanishing point, called the radiant in meteor astronomy, and travel past the observer on either side. Tracing the meteor’s path back to a location above Betelgeuse will ensure that you have just witnessed an Orionid meteor, a piece of Halley’s debris. Observers should face the radiant, southeast to south, but to maximize rates look directly overhead where the sky is the darkest. Allowing the radiant to gain some altitude is usually good advice too because you’ll be able to catch meteors streaming from below as well as from above the radiant position. That happens after 2 a.m. Whether it is frost, dew, or wind, a Halloween chill seems to be the all-pervasive downer that drives most people indoors after a few hours of observing. It gets worse with the Leonids which max this year on November 17 around 6 a.m. EST (no moon, hourly rates of 10 meteors/hour). The ultimate chill, however, is the December Geminids which have a broad peak from the evening of December 13 through the morning of December 14 (100 meteors/hour). I have done several all-nighters with the Orionids and Leonids, but the best I have ever achieved is three hours with the Geminids, and that was with six hand warmers stuffed into various pockets. This year, even for the Orionids, I’m thinking electric—a small electric blanket in my sleeping bag, cushioned by an air mattress, and a pillow or two for my head. With all of those creature comforts, I may be asleep in an hour or two. Don’t forget the hot coffee to keep you awake. Much success in seeing bits and pieces of Halley’s Comet on the morning of October 21 masking themselves as Orionid meteors.

1262 OCTOBER 25, 2020: Blue Moon Halloween: Two of my good friends, Matt and Marcella Gustantino, used to throw a huge Halloween bash which started as the trick-or-treat portion of the evening. There were so many ghoulish and animated objects in the Gustantino’s driveway and garage that some younger kids simply stood there too scared to enter the inner sanctum for their treat. Over the screams coming from the displays and then the kids, Matt would stay in the shadows issuing a continuous monologue of snarky comments from his wrist microphone. I was the photographer, but I also thought, “Wouldn’t it be fun one year to bring along my telescope and treat the kids to a view of the moon when it was full?” During the 15 years that I participated in this event, no Halloween full moon occurred. The years 1906, 1925, and 1944, however, hosted All Hallows’ Eve full moons over every US time zone. The year 1944 was also the last East Coast Halloween full moon too. During the 21st century, only 2020 and 2039 will meet this criterion for all US time zones. A full moon on Halloween does occur every 19 years somewhere in the world, but not necessarily affecting all 50 states. For the East Coast, 1906, 1925, 1944, 2020, 2039, 2058, 2077, and 2096 all boast full moons on Halloween. The other interesting aspect of an All Hallows’ Eve full moon is that it must always be a blue moon, the second full moon happening within the same month. Luna takes 29.53 days on the average to go through a complete cycle of phases. So if a full moon happens anytime on October 31, it must be a blue moon by definition, since the first full moon would have transpired on the 1st or 2nd of October. Blue moons occur infrequently, about every 2-3 years. The phrase "once in a blue moon" has the concept of a long time span and dates back to 1821. However, the origin of the words, "Blue Moon," in reference to astronomy seems to be strictly 20th century. First cited in print in the Maine Farmers’ Almanac of 1937, the blue moon there did not have “the double moon in a month” connotation that it has today. A blue moon was referenced as the third full moon in a four-moon cycle, arising over a three-month time interval. The publication gave religious significance to the usual 12 full moons that occurred within a year’s time. These names were in phase with the ecclesiastical calendar, but would become out of step if a year had 13 full moons. Hence, the rogue full moon (third moon) in a three-month cycle that had four full moons was termed “the blue moon.” All was well until the term surfaced in 1943 and 1946 in Sky and Telescope magazine articles. It was the latter citation by amateur astronomer James H. Pruett, who mistakenly used the blue moon as we refer to it today. Debra Byrd in 1980 used the blue moon as Pruett did in her public radio program, Star Date, giving the term national recognition. By 1985, The Kid’s World Almanac gave the newer astronomical term another boost. The following year, the blue moon was adopted for use in Trivial Pursuit; however, when two full moons occurred in May of 1988, the international press spread blue moon fever far and wide. The decade of the 1980’s ended with a New Year’s Eve blue moon on December 31, 1990, sealing the acceptance of the new definition for good. Indeed, the evolution of the blue moon as it is used today in astronomy seems to have occurred right under our noses and within the easy span of a human lifetime.