September 19, 2023

AstroCal – October 2023



Let us check and see if we will be getting our traditional (and spooky) Full Moon for Halloween this year.  Rats!  As Maxwell Smart used to say on Get Smart!, “Missed it by that much.”  The Full Moon on October 28 means it will still be bright on All Hallow’s Eve, so you still have a chance of catching that elusive ‘witch riding a broom silhouetted against a (nearly) full Moon’ many favor as their holiday decorations.  The Lunar Cycle for October will feature an Annular Solar Eclipse that will coincide with the Oct 14 New Moon with those living in the path from Oregon to the New Mexico/Texas border having the best view.  During an Annular Solar Eclipse, the Moon is too far from the Earth to completely obscure the disk of the Sun.  What is seen is a ‘ring’ or ‘annulus’ of sunlight during totality.  As with a Total Eclipse, areas outside of the path of totality will see part of the Sun’s disk in shadow.  The Great Lakes region will see between a 30 and 40 percent occultation of the Sun.  Caution:  do NOT look directly at the eclipsed Sun unless you have approved viewing lenses or filters or you will do permanent damage to the retina of your eyes.  Unlike other tissue, retinal tissue does NOT regenerate.

The Last Quarter Moon before the New Moon is slated for Oct 6 with the First Quarter falling on Oct 21.  The first thin sliver of a Young Crescent Moon should be visible low in the western sky 40 minutes after sunset on Oct-17.  The growing Crescent Moon will rise higher in the SW sky one hour after sunset – look for it in the middle of The Teapot Asterism in Sagittarius, the Archer on October 20.

How about the morning planets in October?  Venus will reach its greatest elongation on October 23rd when it will be 46 degrees west of the Sun.  At the beginning of the month, it will be a crescent covering 37 percent of the planet, increasing to a gibbous phase (more than half but less than full) of 54 percent.  Venus’s angular size will shrink during the month but it will still present a dazzling object (-4.8 magnitude)in the eastern sky two hours before sunrise.

Jupiter will be shining at magnitude -2.9 in the western sky throughout the month.  While it will not be quite as bright as Venus in the eastern sky, it will be easy to spot.  You can watch Jupiter sink closer to the horizon as the month passes and it approaches opposition early in November.  On Sunday, Oct 29, one can use the Moon as a guide to find faint Uranus slightly below and to the Moon’s right (left and slightly below Jupiter).  At a faint 5.7 magnitude (remember, the lower the number, the brighter the object), binoculars may be needed to see Uranus through the glow of the nearby Moon.  Without the Moon to aide you, look for Uranus halfway between the Pleiades Star Cluster (in Taurus the Bull) and Jupiter.

With its brighter cousin occupying the morning sky, Saturn will be the second the big dog in the night sky.  Why?  Because Jupiter will actually rise in the east two hours after sunset.  It will traverse the nigh sky to become the early morning object low in the western sky described above.  Look for Saturn in the SE sky after dusk and follow it among the stars of Aquarius – the Water Bearer as they cross the night sky.  Faint Neptune (7.7 magnitude) will definitely need a small scope to find to the left of Saturn in the constellation of Pisces, the Fish.

Saturn is our object of interest for our historical shout-out in this AstroCal.  In 1659, Christiaan Huygens realized that the ‘appendages’ (some called them ‘ears’) of Saturn are actually rings.  Huygens watched the appendages disappear in 1665 and reappear several years later.  He realized that the appendages were really flat rings that disappeared when viewed on edge.  (Historical information courtesy of John D. Fix at Astronomy – Journey to the Cosmic Frontier).

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 X at  Yearly subscriptions cost $12 and can be started anytime.


Top Piece Video: Any better time for BOC and Harvest Moon Live than October?