In the Sky This Month

The body and tail of the Great Bear form the Big Dipper. But you have to go a long way from the dipper to find the bear’s nose. It is marked by Muscida, a name that means “muzzle.” The star is well above the dipper at nightfall.

Canopus, the second-brightest star in the night sky, is an easy target for skywatchers south of about Little Rock. It’s just above the southern horizon about 90 minutes after sunset. It’s almost directly below Sirius, which is the night sky’s brightest star.

Sirius, the night sky’s brightest star, arcs across the southwest on March nights. It is low in the south-southeast at nightfall and wheels westward later on. Not only is it bright, it’s also quite twinkly – it shifts colors in the blink of an eye.

Our three closest celestial neighbors highlight the early evening sky: the Moon and the planets Venus and Mercury. Venus is the brilliant Evening Star. Fainter Mercury stands well below the Moon, so it is easy to miss in the glow of twilight.

Mars is in grand view. The planet passed closest to Earth a few weeks ago so it’s still pretty close. It looks like a bright orange star, high in the east at nightfall. Castor and Pollux, the twin stars of Gemini, line up to its left and lower left, respectively.

The Moon is new today as it crosses between Earth and the Sun. It is hidden in the Sun’s glare. It will return to view on Saturday as a thin crescent, low in the west during evening twilight.

Most stars begin their lives in colorful style, inside giant, glowing clouds of gas and dust. One example is the Rosette Nebula, which looks like a delicate rose. It is in Monoceros, the unicorn, and is high in the south-southeast at nightfall.

A pinwheel and a whirlpool both spin away near the Big Dipper’s handle. They are two of the closest and most beautiful spiral galaxies in the sky. Both are visible through small telescopes: M101, the Pinwheel; and M51, the Whirlpool.

Mars is stationary today, appearing to stand still against the background of stars, a result of the angle and relative motions of Mars and Earth in their orbits. After today, the planet will resume its normal eastward motion.

The star cluster Messier 41 trots along with the Dog Star, Sirius, the brightest star in the night sky. They stand due south about 9 p.m., with the cluster directly below Sirius. Under dark skies, M42 is just visible to the eye alone as a small, hazy patch of light.