Sneak Peek at the Summer Sky
Last updated 3/3/2021 at 11:06am
If you’re like I am, you long for summertime, not only for its warm weather and abundant growth but also because its nighttime sky is among the richest of the year.
So it’s usually around late February that I begin wandering outdoors before dawn to sneak a peek at the stars that will appear in the evening sky just a few months down the road.
There’s no great mystery about why the early morning sky appears different than that of the evening; our planet rotates on its axis once every day, and as we spin with it, we face outward in different directions at different times.
This week, evening stargazers face the stars associated with the Northern Hemisphere winter, toward constellations such as Orion and Taurus shining brightly in the southern sky after dark. They are followed closely behind by those of early spring: Cancer, Leo and even the Big Dipper. By dawn, however, the Earth will have turned us far enough around that those star groupings will be replaced by others – those that make up what we know as the summertime sky.
The true splendor of this part of the heavens can only be enjoyed by viewing it from rural areas without light pollution. That’s because its main feature is the wispy band of the Milky Way that you’ll see arching low across the eastern sky.
Begin your celestial trek low in the northeastern sky. There you will find the faintest part of the Milky Way passing through the “W” shape of the constellation Cassiopeia, the queen. As you follow it toward the right, you will soon encounter three bright stars – Vega Deneb and Altair – that outline the shape of what Northern Hemisphere stargazers know as the Summer Triangle. This large geometrical shape offers a convenient milepost because the Milky Way passes directly through its center.
Farther to the southeast, you’ll see the Milky Way flow past the celestial arachnid known as Scorpius, the scorpion.
Scorpius is one of the few constellations that actually resembles its namesake, with its claws at the top, its bright reddish-orange star Antares representing its heart, and its long curving tail and stinger very low against the horizon.
The first thing you may notice about the Milky Way is that it’s not uniform in brightness. It is instead mottled with dark rifts along its entire length. These are known to astronomers as giant molecular clouds, or GMCs, massive globs of interstellar material that stand in stark silhouette against the Milky Way’s brighter stellar band. It is within these GMCs that massive star- and planet-forming regions exist, hidden from eyes not privileged enough to be peering with infrared telescopes.
While you’re gazing at the Milky Way, don’t limit yourself to viewing with your eyes alone. Binoculars reveal countless stars, star clusters and gaseous nebulae invisible to the eye – “deep-sky” objects that beg to be studied further with a small telescope.
Now if you just can’t tear yourself from a warm bed to check out this early-morning celestial tapestry, I certainly understand. Simply mark your calendar, because in only a few months, this amazing sky will appear above you at a less ungodly hour!
Visit Dennis Mammana at dennismammana.com.