Space nerds rejoice! You can now hunt for exoplanets from the comfort of your own backyard with just a few pieces of simple equipment.
IEEE Spectrum senior editor David Schneider recently wrote an article about how he used a DSLR camera, along with a telephoto lens, to search the skies for a specific planet outside our solar system.
Basically, this means you don't need your own Kepler space telescope for planet hunting, although this do-it-yourself method generally requires knowledge of specific exoplanets to begin with.
"I was simply trying to detect the signature of a known exoplanet, one that was discovered years ago with far more sophisticated gear," says Schneider. "I knew exactly which star to look at, when the transit occurs, and what the change in brightness would be. I relied on the expertise of professional astronomers to provide all that information."
So how does it work?
First you need to understand how something like the Kepler telescope finds exoplanets. Kepler spots an exoplanet based on when it transits, or passes in front of, its star. This creates a change in the brightness of that star. Schneider chose exoplanet HD 189733, which is about 63 light-years away from Earth. Its transit happens about every few days.
Next, Schneider purchased equipment, including a 300-millimeter Nikon telephoto lens for his Canon EOS Rebel XS DSLR camera. He also bought a Nikon-to-Canon adapter. His total amount spent for these two items was only around $100.
However, the next task was trickier: Schneider needed the camera to track HD 189733's star during long exposures. A professional star tracker costs several hundred dollars, so he built his own using plywood, gears from an inkjet printer and an Arduino microprocessor.
Getting the images took patience because the exoplanet was often transiting its star during daytime on Earth, plus there's no accounting for cloudy skies and inclement weather. Eventually, weeks after putting his equipment together, Schneider captured photos of the transiting exoplanet.
Once Schneider got his photos , he ran them through software called Iris, which is for astronomical imaging. That helped him pick out the exoplanet in his images.
For those aspiring astrophotographers wanting to recreate Schneider's experiment, he goes into full detail on his article about the process. Of course, you're probably not going to find a new exoplanet this way, but you can confirm the existence of one we already know about, and that, in and of itself, is exciting.
"My project merely highlights that you can get your feet wet in this area with some really cheap hardware," says Schneider said.
[Photo Credit: ESA; Hubble, M. Kornmesser; and ESO, L. Calçada and L. L. Christensen]
