The constellations Leo (upper right) and the faint, but beautiful Coma Berenices (left of center) grace the spring skies. The glow above the tree is the Zodiacal Light (sunlight reflecting off of interplanetary dust particles). The lighting on the tree and land around it is compliments of the lights at the intersection of Avenida Vista Grande and Route 285. ©Eric Saltmarsh

“Spring constellations are relatively lacking in bright stars, star clusters, and nebulae since we’re looking away from the Milky Way.”

The March Night Sky

– Eric Saltmarsh

The March night sky opens with Leo, the first spring constellation, rising in the east as darkness falls. By month’s end, Virgo pursues Leo into the sky after sunset, followed by Libra, which rises about 11pm MDT.

Spring constellations are relatively lacking in bright stars, star clusters, and nebulae since we’re looking away from the Milky Way. However, what they lack in clusters and nebulae, they more than make up for by offering a window beyond the Milky Way, where other galaxies abound. By studying other galaxies, we can learn about the evolution of our own. Unfortunately, you need a good-sized telescope to view most of these far away objects.

Galaxies beyond our own offer a special glimpse into the universe’s distant past. While most objects within the Milky Way are tens to thousands of light-years away from Earth (a light-year is the distance light travels in one year – 5.9 trillion miles), galaxies are millions, even billions of light-years distant.

The light we see from a galaxy, say 100 million light-years away, left that galaxy 100 million years ago – long before there was life on Earth. Now let’s suggest that this hypothetical galaxy had a cataclysmic explosion within its core, say 20 million years ago. We won’t know about that until light from that event reaches us, 80 million years from now. The scale of the universe boggles the mind.

The farthest known galaxy is 13 billion light-years away. The light we receive from that galaxy tonight, left the galaxy only about 500 million years after the ‘Big Bang’ – the creation of the universe. So, studying distant galaxies not only teaches us about the evolution of galaxies, but about the evolution of the universe, as well.

March Planets

March opens with speedy Mercury and sluggish Jupiter making a tight planetary pair in the dawn sky. They will be at conjunction (closest to one another) on March 5th. This is a very favorable pairing of the two planets since Mercury is close to its greatest western elongation, meaning that it’s about as far from the Sun as it gets.

The two planets rise in early dawn, about 5:20am MST. Saturn isn’t far away, just to the upper right of the Mercury-Jupiter pair. By the 10th of the month, the two planets will be well-separated, with Jupiter continuing to rise earlier and Mercury heading back toward the Sun. By month’s end, Jupiter follows Saturn into the pre-dawn sky. Mercury is now a difficult object, rising at about 6:25am MDT.

Fading Mars opens March near the Pleiades star cluster in Taurus. The Moon passes close to Mars on the evening of the 19th.

Venus is too close to the Sun to be seen this month.

March 5, 2021 Jupiter Mercury Conjunction
Jupiter & Mercury are close together in the March 5 early morning sky. Graphic courtesy EarthSky.Org
Vega, Deneb, & Circumpolar Stars
In this photograph, stars within the yellow arc are circumpolar. The arc is part of a circle encompassing all circumpolar stars seen from our location. Vega and Deneb are not circumpolar here, but they’re high enough in the northern sky that, in late fall/early winter, they set in the northwest after sunset and rise in the northeast before the next sunrise. ©Eric Saltmarsh

March Spotlight: Circumpolar Stars

From the northern hemisphere, Polaris (a.k.a., North Star, Pole Star) seems to stand still in the sky, while the rest of the stars revolve around it. It sits less than one degree from the ‘North Celestial Pole,’ the point directly above Earth’s North Pole. While there are stars closer to the North Celestial Pole than Polaris, they’re all very faint.

While many stars seen from our area rise and set due to the Earth’s rotation, those near Polaris rotate around it, remaining visible all night, all year. These are known as ‘circumpolar stars.’

If we were at the equator, Polaris would be sitting on the north horizon, never appearing to move. However, because Santa Fe sits 35 degrees north of the equator, Polaris appears 35 degrees above the north horizon. As a result, any stars within a radius of 35 degrees of Polaris are circumpolar, as seen from our latitude.

March Night Sky Events

March 3: Mars passes 2.6 degrees from the Pleiades star cluster.

March 5: Mercury and Jupiter are in conjunction, rising together during dawn.

March 6: Mercury is at its farthest from the Sun in the dawn sky (greatest western elongation), in Capricorn, to the lower left of Jupiter. It forms a nice pair with Jupiter during the first week or so.

March 13: New moon.

March 19: The first quarter Moon passes close to Mars in the constellation Taurus.

March 20: Vernal equinox occurs at 6:27am MDT. The Sun is directly over the equator, moving north. This is the first day of spring in the northern hemisphere.

March 28: The full Crow Moon occurs at 12:49pm MDT in the constellation Virgo.

March 31: By month’s end, Jupiter and Saturn rise before dawn in the constellation Capricorn.

Circumpolar stars
Due to the long exposure, the stars appear as lines since they’re constantly rotating around the North Celestial Pole. Polaris is the closest bright star to the North Celestial Pole. But, since it’s not right on the pole, it endlessly circles it, like all the other stars in the photo. ©Eric Saltmarsh


Disabled train against the circumpolar stars
A disabled train engine facing due south provides an interesting foreground object as circumpolar stars rotate around Polaris (top center). The glow to the left of the train is light pollution from the Santa Fe area. ©Eric Saltmarsh