Guest post by Peter Thompson, co-founder of Astronomy for Beginners
Above your head every night, there is a light show that will take your breath away. That is, it will take your breath away if you can see it. The universe, in all its splendor, presents an encore presentation of this spectacular show each night, with seasonal twists and turns. Increasingly, however, poor lighting practices make it difficult to enjoy nature’s gift.
Growing up in a big city, it can be difficult to appreciate a true, dark night sky. With so much happening on the ground, we can forget to look up. When we do have the opportunity to gaze upon the night sky, the display can be limited by light pollution. Take Los Angeles, for instance. Within the city, you may see the brightest stars the night has to offer, unless you’re standing under a street lamp or on a brightly lit boulevard. But being invited to a telescope party nearly 100 miles north of L.A. could completely change your view of the world.
When you arrive, it’s still twilight. People are standing next to their scopes, adding the finishing touches to set them up for a night of stargazing. As the last embers of daylight are extinguished on the western horizon, there is only one cloud in the sky. And as the minutes wear on that one cloud comes into sharp focus, unchanging, except in growing clarity. That cloud is hundreds of light years above the sky. It is made not of mist, but of millions of stars in the Alpha Quadrant of our Milky Way galaxy.
Each star seems so much brighter than you’re used to. And there are so many of them! The simple constellations visible from a dark hillside in Los Angeles are now filled with dozens of other stars. They were always present, but invisible under the loud glare of light pollution.
From this new vantage point, you can still see the light of the big city. It covers the southern horizon with a wall of faint light, like an approaching sunrise that never arrives. The remainder of the sky, however, is pristine. Your heart swells to take it all in. You move from one telescope to the next. The owners are more than happy to show off their pride and joy. Each scope is set up to view a favorite cluster, double star, or other night sky feature.
In the distance, about four miles away, a car moves along a highway, its headlights painful to look at. On a brightly lit street, these headlights blend softly with the surroundings. But here, as your eyes have adjusted to the darkness, the glare of that distant vehicle is like a jackhammer interrupting the lyrical strains of delicate music. You begin to wonder “How much artificial light do we really need?” You realize that the stars provide more than enough light to delight the senses and ground you safely in your environment.
The Beginner Astronomer
When we discover a new hobby, we keep at for the joy it brings us. Once we’ve covered the bases of this new found interest, we find more to tantalize our minds, eager to explore more deeply. For the beginner astronomer, it’s no different.
After enjoying a star party or two, we might consider getting our own telescope. We go online to research what telescopes are available. We set a budget, and find the scope that gives us the best aperture (size of opening to let light in) and optics (lenses) we can afford. We might even get a motor-driven scope so that the image doesn’t keep slipping out of view as the Earth rotates. The truly serious amateur astronomer may want to get a computerized telescope with built-in GPS. These features can cover many of the details of finding a star and allowing you to sit back and enjoy the viewing.
But then, you are faced with a problem. Your nice, large aperture lets in lots of wonderful starlight, alongside the visual “noise” of light pollution. If you set up your scope near a poorly lit urban area, you’re going to get an eye full of the artificial light from the city being scattered by the sky.
Consider how blue the sky looks during the day. That’s the sun’s light being scattered by the sky. The same is true of a full moon. The bright glow of the moon radiates outward and everything near that brilliant body is drowned out by its glow.
If you turn your telescope to the blue sky of day, you might be able to see Venus, on occasion, if you know exactly where to look (Sessions and Byrd, 2018). This can be a neat trick, but it drives home the point about light pollution. The glow of the sun, during the day, makes it difficult to find Venus, and impossible to see the other stars. Skyglow from light pollution makes it more difficult to see many of the background stars that add to the rich joy of stargazing.
The most experienced astronomers can work around light pollution. Their well-practiced eyes can detect things the beginner’s eye might miss. But where’s the fun of listening to your favorite music with heavy construction noise drowning out all but the loudest parts? Luckily, light pollution is easily reversible. With responsible outdoor lighting practices, brightly lit areas can reduce excessive lighting and protect the night sky for amateur and expert astronomers alike. Combating light pollution also benefits wildlife, human health, and the economy.
If you are passionate about introducing newcomers to astronomy and making the hobby more accessible to city-dwellers, consider getting involved in the fight against light pollution. Talk to your neighbors about how they can improve the lighting around their homes, bring up the issue with your local government, and spread the word about the importance of protecting dark skies in your community. Your fellow astronomers will appreciate your efforts and you’ll be rewarded with the night sky’s spectacular show, in the comfort of your backyard.
Astronomy for Beginners. (ND). Retrieved on May 15, 2019 from https:// astronomyforbeginners.com/
Sessions, Larry, and Byrd, Deborah. (November 12, 2018). “How to see Venus in daytime.” Retrieved on May 15,2019 from https://earthsky.org/space/how-to-see-the- brightest-planet-venus-in-a-blue-daytime-sky.