September 18, 2022

AstroCal – October 2022


     Let us start this month’s AstroCal with a lesser known object visible in the evening sky one hour after sunset.  The constellation it is found in is an easily recognized Sign of the Zodiac, Pisces, the Fish.  Pisces forms a rather large ‘V’ shape that is tilted somewhat to the right.  At the end of the lower section of the ‘V’ there is an asterism formed by the stars Gamma, Theta, Iota, Lambda, and Kappa Piscium.  (Two notes:  an asterism is a recognizable formation of stars (like the Big Dipper found in Ursa Major, the Great Bear) located within a larger constellation.  Greek letters are used to rank the stars in any constellation by their brightness).  In this case, the asterism located in Pisces is known as The Circlet of Pisces and it should be easily visible just above Jupiter an hour after sunset in the ESE.  

     Speaking of evening planets, Jupiter is the star of the show all night long, shining at a brilliant -2.9 to -2.8 this month.  Starting an hour after sunset, look for this Gas Giant well above the horizon between E and ESE.  On Oct 8, it will be directly above the Full Moon.  Jupiter will move 3.3 degrees against the background of stars this month (known as retrograde motion,

caused by the Earth catching up to and passing the orbit of the more distant Jupiter.  Don’t forget to view the planet with binoculars or a small spotting scope.  Even with that level of magnification, it is possible to see the four largest Jovian moons (the so-called Galilean Moons named after Galileo, the first to see them with one of the first telescopes).  Saturn will be less bright at +0.5 to +0.6 during the month.  On Oct 1, Saturn will be located in Capricornus, the Sea Goat, 44 degrees (a closed ‘fist’held at arm’s length equals about ten degrees, so measure about four fists) above and to the right of Jupiter.  This distance will be reduced to 41 degrees by Oct 31.  Both planets will be visible all night long making for prime viewing all month.

     Jupiter’s positioning means it can also be seen as a morning planet in October.  Look for it in the WSW two hours before sunrise between October 8 and 11.  With the Full Moon just below Jupiter on Oct 8, one may be able to spot Neptune just to the right of the Moon.  With a magnitude of just +7.8, this would be a great observing challenge for the month.

     Mercury reappears early in the month.  Look for it in the morning sky close to the eastern horizon as it brightens quickly from +1.2 to +0.2 between October 1& 4.  Mercury will continue to climb higher until it reaches its greatest elongation (18 degrees from the Sun) and a magnitude of -0.5.  Mars will shine at magnitude -0.6 to -1.2 high in the SW quadrant during October. Look for the Gibbous Moon to be just above the Red Planet on Oct 15.  On Oct 30, Mars will begin a 74 day period of retrograde motion – visit the Sky Calendar Extra Content Page at the Abrams Planetarium site listed below to see a chart depicting this path.  Mars viewing will continue to improve into December when it will reach a brilliant -1.9 magnitude as it nears opposition.

     The month will begin with the First Quarter Moon on Oct 2, followed by the Oct 8 Full Moon, the Last Quarter Moon on Oct 17, and the New Moon on October 25.  You can break out the binoculars on October 26 and see the young 3 percent crescent Moon 3 degrees above the horizon, 30 degrees S of W.  Again, we won’t get to see a Full Halloween Moon on October 31, but it will at least be a First Quarter Oct 31-Nov 1.  Hey, that is better than nothing, right?

    Compiled by Ken Raisanen of WOAS-FM – information provided by Abrams Planetarium Sky Calendar, Michigan State University.  More information and subscription information can be found on their website at or on Twitter at  Yearly subscriptions cost $12 and can be started anytime.  


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