In the previous installment of this series, we learned how star maps help astrophotographers in Alameda locate objects millions of light years away. Today you’ll see how these photos get their mesmerizing colors thanks to false color techniques, but it isn’t as fake as it sounds! Finally, you’ll learn how you can take a picture of our own galaxy using any camera—even analog film—and a tripod.
June is the month of color—Pride Month. As seasonal rain subsides, rainbow flags take the place of rainbows in the sky. As you may know, a rainbow is light being split into multiple colors through water. So, if rainbows are H2O plus sunlight, are they even physical objects at all? Or are they “H2O artifacts?” Observing and photographing celestial objects raises a similar question.
Pride Month is a reminder that color is expressive. Astrophotography offers a similar opportunity to color the universe however you see fit.
Rainbows aren’t a perfect metaphor, as H2O doesn’t emit light, it just bends and splits it. Still, the idea of light being broken into wavelengths helps us understand how images like the one featured today, the Tadpole Nebula (NGC 189III), can be captured from Alameda. Nebulae like this emit their own light from the chemicals which make up their atomic composition and temperature. The most common emission lines are hydrogen-alpha (Hα), oxygen III (O III), and sulfur (S II). These chemicals emit light in the visible spectrum, but their signals are typically too faint to detect without long exposures and special filters…