Prime Time for Viewing the Milky Way

The Moon was at New phase on August 23rd and as a growing crescent of light, won't be much of a hindrance to stargazing through most of this upcoming week.  Even when it arrives at First Quarter phase on Thursday, August 31st, it will still be setting before midnight, leaving the balance of the night dark and without hindrance from bright moonlight.

This combined with the fact that at this particular time of the year many people enjoying some leisure time in rural settings where skies are dark means that this is the optimum week to check out the beautiful summer Milky Way. 

As soon as darkness falls, it becomes evident as a wide glowing arch of variety and beauty, stretching across the sky from the northeast to southwest. 

Sweep with binoculars from the Scorpion's tail, through the Summer Triangle, and then down to Cassiopeia and Perseus.  You'll find concentrations of stars, clusters, large apparent gaps (such as the "Great Rift" in Cygnus), and more stars than you probably thought existed.

Unfortunately, because of the tremendous increase in light pollution over the past quarter century, the majority of our current generation have never seen the night sky in all its grandeur.  Indeed, the Milky Way has been one of the chief victims of atmospheric pollution - by light and other factors.  In most major metropolitan areas, there is very little hope of seeing this broad path of light at all. 

However, on the night of August 30, 1976, I stumbled across an old observing logbook of mine where I noted that I was able to glimpse the stretch through Cygnus from the Throggs Neck section of The Bronx!  It was one of those evenings, so rare in the summertime, with unusually low humidity and crisp, very transparent skies. 

Sadly, I should point out, that even if the same weather pattern were to recur tonight, I wouldn't be able to repeat my observation of 30 years ago, because the junior high school across the street where I used to live has since installed brilliant security lighting on its roof.  So bright are the surroundings now that you can readily read a newspaper in the middle of the night, if you were so inclined.

Our eyes have some detail-discerning properties that not even the best long-exposure photograph can match.  This advantage is considerable in the case of the Milky Way, which has such great extent that it does not require a telescope. I can recall with great fondness one particular night spent under the dark skies of upstate New York's Adirondack Mountains where I spent a considerable amount of time savoring the Milky Way in all of its magnificence.  So clear was the sky, that rather than appearing as a filmy band of light, the Milky Way appeared granulated in texture, and glowed so bright that it actually cast faint shadows! 

I must now confess here, however, that even though I had my trusty 7 x 35 wide-angle binoculars, I hardly used them at all that night, except to pick out deep-sky objects (star clusters or nebulae) of interest.  Looking at Via Lactea (the Milky Way's Latin name) through binoculars - except to view certain highlights - is a kin to closely scrutinizing a painting with a magnifying glass, which only reveals the coarse canvas, and not the actual art itself.

Before the invention of the telescope, the true nature of the Milky Way Galaxy ("Gala" is Greek for milk) was a mystery.  Our galaxy's center is about 30,000 light years away toward the Sagittarius star cloud; its outer edge is about 20,000 light years in the opposite direction (toward Auriga and Taurus). The Sun and all the outer stars of the galaxy revolve around it at the rate of 155 miles per second.  It apparently requires about 200 million of our Earthly years to make one complete revolution, or one "cosmic year," around the center of our galaxy.

When we began to realize that there were other such vast congeries of stars, we called them "island universes," but this was an obvious misnomer; since universe means everything there is, it can hardly have a plural.  So we've seemed to settle on galaxies, which is a compromise as a new meaning for an old word.

Basic Sky Guides

• Full Moon Fever
• Astrophotography 101
• Sky Calendar & Moon Phases
• 10 Steps to Rewarding Stargazing
• Understanding the Ecliptic and the Zodiac
• False Dawn: All about the Zodiacal Light
• Reading Weather in the Sun, Moon and Stars
• How and Why the Night Sky Changes with the Seasons
• Night Sky Main Page: More Skywatching News & Features

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.