October Astronomical Potpourri

October 2020  :  Dave Huestis

As the title of this column suggests, the month of October will have something for the naked-eye and telescope user alike. Hopefully the heat and humidity of this past summer will be behind us, leaving cooler temperatures and transparent skies so we may comfortably and efficiently scan the skies for interesting astronomical phenomena. 

Draconid and Orionid Meteor Showers

This month the sky gods reward stargazers with two meteor showers. The first one is a minor one, the Draconids, on the evening of October 7. Currently producing ten or less yellowish slow-moving (hitting the Earth’s atmosphere at only 14 miles per second) meteors per hour, it is best observed once darkness has fallen through the midnight hour when the constellation Draco is highest in the northern sky. This scenario allows you to get that much needed beauty sleep!

Look towards the north and locate Ursa Major (the Big Bear/Dipper). Draco is a sinuous pattern of stars that stretches between Ursa Major and Polaris, the pole star, which is the end star in Ursa Minor (the Little Bear/Dipper), tail/handle. While the meteors will emanate from this region of the sky, scan east and west up to zenith (directly overhead). As the night progresses, watch the northern sky rotate around Polaris. By morning twilight, Draco’s head will be sitting due north about 20 degrees above the horizon. A bright waning gibbous Moon will rise locally around 9:30 p.m., so it will wash out some of the fainter meteors.

The second meteor shower of the month, the Orionis, is a major one, occurring on the night of October 20-21. The best viewing opportunity will be between midnight and dawn’s early light. A waxing crescent Moon will set soon after sunset and will not interfere with observing as many meteors as possible. Just position yourself away from any light sources to maximize your shooting star count. At their peak of activity, you can perhaps observe up to about 20 or so yellow and green meteors per hour.   

These meteors appear to radiate out of the sky just above Orion’s head (hence the name of the shower) and not far from the bright red super giant star Betelgeuse, which marks his right shoulder. The Orionid meteors disintegrate in our atmosphere around 41.6 miles per second, and they are also noted for producing fireballs that create persistent dust trains as they blaze across the sky. While Orion is an easy star pattern to identify, at 3:00 a.m. this giant constellation will be found high in the southeast sky.

Close Encounter with Mars

Every 26 months the “Red Planet” Mars and Earth are closest to one another. On October 6 our planetary neighbor will be only 38.6 million miles away. That distance is just a little farther away than Mars was at its last close approach on July 31, 2018. You may remember there was much anticipation of that event, but a global Martian dust storm enshrouded the planet, preventing any telescopic observations of its surface features. This upcoming close encounter promises much better viewing opportunities.

Why? Mars experiences seasons like those on Earth. At this time of close approach there will not be a high probability of large Martian dust storms. Also, for 2020 Mars will rise much higher into our less hazy October sky than it did back in 2018. A telescope should reveal much detail on the Martian surface.

If you would like some background on the history of Mars exploration please visit this link on the Skyscrapers web site: http://www.theskyscrapers.org/mars-past-present-and-future.

Since I expect the local observatories to still be closed due to Covid-19 (with the possible exception of Frosty Drew in Charlestown - https://frostydrew.org/2020-contagion.php), I strongly encourage everyone to drag out those telescopes from the basement, attic or garage and treat yourself and your children to the best views of Mars we’ll experience until 2035. One day they or your grandchildren may set foot upon this exciting landscape. Take a knowledgeable glimpse of an alien world that inspired generations of astronomers and science fiction writers alike to ponder the existence of Martian life-forms.

This brief Mars observing guide will help you to discern and appreciate the planetary detail a telescope may show you of this neighboring world. Considering how close our two worlds will be, even a small 2.4-inch refractor should show some surface features. And if seeing conditions are perfect, one should be able to “crank up” the magnification to coax additional detail out of the image. Larger aperture telescopes will reveal increasing detail.

Mars will not be difficult to locate in the sky. On the night of close approach Mars will be seen just above the eastern horizon during late evening twilight. You won’t be able to mistake its distinct bright pumpkin-orange color. You should wait for the planet to climb higher into the sky and out of any horizon haze and turbulence before you begin telescopic observation of this world. By 9:00 p.m. Mars will be about 25 degrees above the horizon and awaiting your scrutiny among the stars of the constellation Pisces and will remain in this constellation through the end of 2020.

Once you focus in on Mars with a telescope, closer inspection will reveal the surface color to be more peach-like. The second detail that should catch your eye will be the South Polar Cap (SPC). It’s a fairly bright white feature that can be easily seen because Mars’ south pole is currently tilted towards the Earth.

As you more carefully scan the planet you should begin to notice several dark surface features. These markings are the underlying rock exposed by the shifting sands during intense planetary dust storms. The amount of detail seen will depend upon the size of your telescope and its magnification. However, atmospheric conditions above your observing location will be the definitive limiting factor.    

Keep in mind you don’t have to identify the features you glimpse. Just simply enjoy the view.