The Evening Sky in March 2023
Download a PDF containing this chart, additional charts for specific areas of the sky and descriptions of interesting objects visible at this time of year.
At the beginning of the month the bright planets, Venus and Jupiter make an eye-catching pair low in the western twilight soon after sunset. On March 3rd they will be 1° apart, two full moon widths. (They aren’t on the chart as they set well before 9 pm.) Over the month Venus holds its position in the twilight, setting 70 minutes after the Sun. Jupiter slips steadily lower, gradually disappearing. The thin crescent Moon will be near Venus on the 24th. Mars is the only naked-eye planet in the later evening sky. It looks like an orange-red star low in the north. It sets in the northwest around midnight mid-month. The Moon will be below Mars on the 28th.
Northwest of the zenith is Sirius, the brightest star in the sky (but out-shone by star-like Venus and Jupiter when they are around). Southwest of the zenith is Canopus, the second brightest star. Below Sirius are bluish Rigel and orange Betelgeuse, the brightest stars in Orion. Between them is a line of three stars: Orion's belt. To southern hemisphere star watchers, the line of three makes the bottom of 'The Pot'. Orion's belt points down and left to a V-shaped pattern of stars. These make the face of Taurus the Bull. The orange star is Aldebaran making one eye of the bull. Continuing the line from Orion down and left finds the Pleiades or Matariki star cluster, setting early.
At the beginning of March Mars, Aldebaran and Betelgeuse make a long (isosceles) triangle of orange stars. Mars holds its position in the sky through the month as Aldebaran and Betelgeuse creep west. By the end of the month the three make an equilateral triangle. Mars fades steadily as we leave it behind. It is like Betelgeuse at the beginning of March. By the end it is like Aldebaran.
Sirius is the brightest star in the sky both because it is relatively close, nine light years* away, and 23 times brighter than the sun. Rigel, above and left of Orion's belt, is a bluish supergiant star, 40 000 times brighter than the sun and much hotter. It is 800 light years away. Orange Betelgeuse, below and right of the line of three, is a red-giant star, cooler than the sun but much bigger and 9000 times brighter. It is 400 light years from us. The handle of "The Pot", or Orion's sword, has the Orion Nebula at its centre; a glowing gas cloud many light-years across and 1300 light years away. It is nicely seen in binoculars.
Near the north skyline are Pollux and Castor marking the heads of Gemini the twins. Above and to the right of them is the star cluster Praesepe, marking the shell of Cancer the crab. Praesepe is also called the Beehive cluster, the reason obvious when it is viewed in binoculars. The cluster is some 500 light years from us.
Crux, the Southern Cross, is in the southeast. Below it are Beta and Alpha Centauri, often called 'The Pointers'. Alpha Centauri is the closest naked-eye star, 4.3 light years away. Beta Centauri, like most of the stars in Crux, is a blue-giant star hundreds of light years away. Canopus is also a very luminous distant star; 13 000 times brighter than the sun and 300 light years away.
The Milky Way is brightest in the southeast toward Crux. It becomes broader lower in the southeast toward Scorpius. Above Crux the Milky Way can be traced to nearly overhead where it fades. It becomes very faint in the north, right of Orion. The Milky Way is our edgewise view of the galaxy, the pancake of billions of stars of which the sun is just one. We are 27,000 light years from the galaxy's centre, below Scorpius.
The Clouds of Magellan, LMC and SMC are high in the south sky, easily seen by eye on a dark moonless night. They are two small galaxies about 160 000 and 200 000 light years away.
Saturn emerges from the dawn twilight during March. By mid-month it is rising due east around 5:20 a.m. It looks like a medium bright,1st magnitude, star with a slightly cream tint, in an empty area of sky. The thin crescent Moon will be by Saturn on the morning of the 20th.
*A light year (l.y.) is the distance that light travels in one year: nearly 10 million million km or 10^13 km. Sunlight takes eight minutes to get here; moonlight about one second. Sunlight reaches Neptune, the outermost major planet, in four hours. It takes sunlight four years to reach the nearest star, Alpha Centauri.
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