Illumination of Earth by the Sun at the March equinox. Image credit: Wikipedia.
After a long, cold, and snowy winter, we all are looking forward to the arrival of spring. So I am happy to announce that the Vernal Equinox(spring equinox), the astronomical first day of spring, occurs on March 20th (Thursday) at exactly 12:57 pm EDT. This means that the Sun appears to intersect the Celestial Equator in the sky, which is located at 50 degrees above the southern horizon for us in Maryland. It also means that the Sun looks to be higher in the sky each day at noon than the previous day, and that overall day-length will be longer than night-length all the way now until June 21st (the date of the Summer Solstice). The Vernal Equinox is also one of two days in the year when the Sun appears to rise exactly due East and to set exactly due West. (the other is the Autumnal Equinox in September).
The Vernal Equinox however does not necessarily mean that winter cannot still raise its head. I recall a late winter March 17th nor-easter snow storm that struck Maryland several years ago. But signs of spring have begun to appear. For example, the zodiac constellation Leo the Lion, has been rising up in the eastern sky already since February, with its distinctive “backwards question mark” shape of six stars. Now in March it is well up in the East as as soon as it gets dark. And all the bright and beautiful winter constellations —– Orion, Taurus, Gemini, Canis Major, and Auriga —- have all shifted over to the west or southwest skies, because of Earth orbiting the Sun. Most are still prominent there however until midnight.
Mars is now just a month away from its first opposition in two years —- when it will be at its best for skywatchers. Opposition is when a planet appears to lie opposite the Sun in the sky as seen from Earth. Thus Mars will rise in the East as the Sun sets in West next month.
For now, in March, Mars rises around 9:30 pm in the East; and by 7:30 pm at the end of the month. It will brighten all month; from –0.5 to –1.3 magnitude, and will be in the best position for seeing from 11 pm to 4 am in the southern sky, among the stars of Virgo.
With only a modest backyard telescope, you can easily see Jupiter’s four largest moons. Image credit: Jan Sandberg
Jupiter remains the brightest evening planet all month, already well up in the East when the Sun sets among the stars of Gemini. It will remain visible there until about 4 am, shining at magnitude –2.3. Saturn rises in the East also —- about 2 hours after Mars —- among Libra’s stars, and will have a magnitude of +0.4. It will be highest in the east-southeast just before morning twilight starts; around 5:30 to 6:30 am.
The brightest planet this month is Venus, which is an early morning object in the southeast sky and which rises 2 hours before sunup. At magnitude –4.5 it is a full 2 magnitudes brighter even than Jupiter. On march 27th the waning crescent Moon will be seen just above Venus at about 6:00 in the morning. Venus is at what we call greatest western elongation from the Sun from March 22nd to April 2nd, which also translates into its greatest altitude above the horizon. We will have no trouble seeing it; it is just so bright!
The Moon will be in conjunction with some of the planets this month too. These always make lovely sights to see as Moon and planet appear close together in the sky. A waxing gibbous Moon will appear just below Jupiter on March 10th; a nearly Full Moon just below Mars on March 18th; and very close and below Saturn on March 20th. Moon phases this month are: 1st quarter on March 8th; Full Moon on March 16th; and 3rd (last) quarter on March 23rd.
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