December 19, 2022

AstroCal – January 2023


     Happy New Year – here is a small and slightly late Christmas present:  As of January 1, we have now regained 6 percent of our lost daylight hours.  We won’t really notice the ‘extra daylight’ for a couple of weeks, but rest assured, the Sun is inching higher in the sky each day and in less than three months, we will already be halfway to the traditional beginning of Summer.  The twelve hours of daylight and darkness we will see on the Vernal (or Spring) Equinox gives us hope of warmer weather to come, but perhaps not so much a happy event for the Winter sports lovers out there.

     We begin our planetary viewing this month with brilliant Venus which will occupy the SW to WSW horizon for about 1.3 hours early in the month to 2.0 hours by the end of January.  Shining at magnitude -3.9, it will be very easy to locate.  The next brightest planet, Jupiter, will stand at -2.4 to -2.2 well up in the S to SW sky at dusk where it can be seen for nearly seven hours before it sets.  Next in magnitude will be -1.2 Mars.  The Red Planet begins the new year in the east and will ascend to a higher point in the ESE by Jan 31.  Saturn will rank fourth in brightness in January at +0.8.  The Ringed Planet begins the month 24 degrees (or two and one half closed fists) to the upper left of Venus but it will will close one degree per day so by Jan 22, they will only be 21 arcminutes apart (about one third of a degree).  Saturn will then be situated to the right of Venus after it passes by and continues to sink closer to the horizon with it setting 1.1 hours after sunset on Jan 31.  A good observing challenge for early in the new year would be to see on what date you will be able to observe Saturn before it slips from view.

     As for the faint planets at nightfall (Neptune and Uranus), more information can be found by visiting the Sky Calendar extras page at .  Mercury will pass inferior conjunction on Jan 7 and brighten to mag +1.1 by Jan 15 and 0.0 on Jan 22.  Mercury will be the highest in the ESE to SE morning twilight around Jan 24 and will reach its greatest elongation of 25 degrees from the Sun on Jan 30.

     The first Full Moon of 2023 will take place on Jan 6 with the Last Quarter following on Jan 14.  With the New Moon ending one Lunar Cycle and beginning the next on Jan 21, the first Young Crescent Moon will peek from low in the SW to WSW horizon 40 minutes after sunset on Jan 22 with Jan 28 marking the First Quarter Moon.  During the times when the Crescent Moon can be seen in areas with good dark sky viewing conditions, it may be possible to see a phenomenon known as Earthshine.  Earthshine can be observed when Sunlight reflecting off the Earth illuminates the darkened side of the Moon.  It normally takes light about 9 minutes to travel the 93 million miles from the Sun to the Earth, but the light we see during Earthshine adds nearly 500,000 miles to the light we see shining off the dark side of the Moon.  Those readers with a mathematical bent should be able to figure how much longer Earthshine light takes to finish its journey.  

     On Jan 30-31, observers along the southern states will see an occultation of Mars by the Moon (in other words the Moon will pass between the Earth and Mars).  Farther north, viewers will see the Moon pass just south of Mars.  For the Great Lakes region, the closest point between the two bodies will take place between 12:38 a.m. and 1:27 a.m. ESTA U.S. map and timetable for additional viewing sites can be found on the extra content page mentioned earlier.  

     Let us take a couple of moments this month to remember the announcement of Miss Mitchell’s Comet.  Maria (pronounced muh rye ah) Mitchell discovered her comet in October of 1847 and the find was released in Sillman’s Journal in January 1848 under her father’s name.  The following month, she submitted the calculations of the comet’s orbit under her own name.  The disparity of opportunities for women astronomers (and scientists in general) led Miss Mitchell to become a staunch advocate for women’s rights.  She was the first American and first woman to be awarded a gold medal prize as the ‘first discoverer’ of a comet by King Christian VIII of Denmark.  Miss Mitchell’s Comet was independently discovered by Francesco de Vico two days after Mitchell discovered it, but he reported it to European authorities.  When the data was compared to the American report, Mitchell was verified as the first discoverer and awarded the gold medal.  Mitchell’s was the third cometary find attributed to a woman after Carloline Herschel and Maria Margarethe Kirch.  Until next time, enjoy the extended early sky observing offered by our long January nights. 

   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. 

Top Piece Video:  Try to find a song about comets – this is about all I could find – Brighteyes with COMET SONG