February 19, 2023

AstroCal – March 2023


     Mark your calendars if you are planning to celebrate the Vernal (or Spring) Equinox.  One of the two days of the year when all points on the globe receive 12 hours of daylight and 12 hours of darkness, this year’s event happens on March 20 at 5:24 p.m. EDT.  What happens at this precise point in time?  The Sun’s vertical ray crosses the Earth’s Equator.  If you happen to be standing somewhere on this imaginary line at that time, the Sun would appear directly overhead.  You may have noted that the time is listed as EDT – that is because the switch over to Daylight Saving Time will occur at 2:00 a.m. on March 12.

     The Sun’s ‘movement’ is actually caused by the Earth’s 23.5 degree tilt from the Earth/Sun plane – while the Earth travels in orbit around the Sun, its axis of rotation always points at the same point in space (Polaris, the North Star).  In the Northern Hemisphere, we are tilted toward the Sun in our summer months and away from the Sun in our winter months.  Earth’s position for the Spring and Fall Equinoxes means neither hemisphere is pointed toward or away, thus giving all points of the globe equal day and night.  ‘Equinox’ literally means ‘equal night’.  I do not know about you, but after the long dark nights of December and January, I am ready to celebrate the halfway point to the longest daylight of the year.

     The Lunar Cycle for March will see the month begin just after the First Quarter Moon of February 27, followed by the Full Moon on March 7, the Last Quarter on March 14, with the New Moon reset to begin the next cycle of phases on March 21.  The last Lunar event for this month will be the First Quarter Moon on March 28.

     The only morning planet of note this month will be Saturn which will enter the morning twilight at mid-month.  Look for The Ringed Planet low in the sky 30 minutes before sunrise.  It will be located in the ESE just left of the old Crescent Moon in the same early twilight on March 19 to give you at least one reference point to look for.

     There are still a host of evening planets one can enjoy this month.  The brightest continue to be Venus and Jupiter which will only be a half a degree apart on March 1.  In other words, they will be as close together as they can get without Venus passing directly in front of Jupiter.

With Venus shining at magnitude -4.0 and Jupiter at mag -2.1, it will be an impressive pairing.  As they pull apart, the distance will increase from half the width of your little finger nail held at arm’s length to twice the distance of a little finger/index finger ‘hook ‘em horns’ salute that spans 15 degrees of the sky.  Changing from .5 degrees to 30 degrees in a month means one can almost see the change in spacing on a nightly basis.  Look for both in the western sky an hour after sunset – they won’t be hard to find.

     Mars begins March 107.3 million miles from Earth, a distance that will increase to 135.2 million miles by the end of the month.  In the simplest terms, Mars will be getting farther away and shrinking.  The Red Planet won’t be difficult to find, either.  It is high overhead and will pass between the tips of the horns of Taurus the Bull on March 11.  As it passes from Taurus to Gemini, the Twins, its magnitude will decrease from 0 to1.  Mercury will move into the evening sky later in the month after reaching superior conjunction on March 17 (it will be easier to locate next month).  Uranus will be faint when Venus passes it on March 29, 30, and 31, but observers may be able to find it shining at mag 5.8 using binoculars or a small telescope under ideal viewing conditions.  Look for the pairing between W and WNW two hours after sunset..

      As long as Venus will be easy to spot all month, it can be used as a guide to find the very young Crescent Moon low in the west 40 minutes after sunset on March 22.  This sliver of Moon will almost appear to be sitting on top of Venus.  The event also marks the start of Ramadan.

     Did you have better luck than I did observing Comet C/2022 E3 (ZFT), otherwise known as the Green Comet?  The weather and full Moon hampered my attempts to spot it but the number of photos posted on various internet sites more than made up for my lack of clear skies.  There is an excellent time-lapse clip created by astrophotographer Miguel Charo that stitches together 521 images he captured over ten hours of observing from an observatory in Portugal.  The Dark Sky Alqueva Observatory averages 286 clear nights per year.  You can find the clip by searching for .  

   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.


Topo Piece Video:  In honor of the Green Comet, here is Skillet with Watching for Comets . . .