Your Run-of-the-Mill Digital Camera Can Now Detect Alien Planets
Astronomy is no stranger to citizen scientists. Amateur stargazers are credited with the discovery of comets, asteroids, and even planets. That said, while amateurs don’t use multi-million dollar observatories, it’s still an expensive hobby. Or rather it was, modern tech, is taking homebrew astronomy to new heights.
How high? Off-the-shelf gear assembled at home for under $500 (used) can observe an object 370 trillion miles from Earth. David Schneider recently detected a planet orbiting a star 63 light years away using naught but a hinged plywood base, a stepper motor, some gears from an inkjet printer, an arduino microprocessor, and a digital camera (with telephoto lens).
The planet, HD 189733 b, was discovered in 2005. Its tight orbit and large mass make it an exoplanet type known as a ‘hot Jupiter’. Many early exoplanet discoveries were like HD 189733 b because their gravitational and light curve effects were more obvious than similar effects from smaller worlds orbiting at greater distances. HD 189733 b is the nearest known hot Jupiter to Earth. Together, these characteristics made the planet an ideal candidate for Schneider’s project.
His first challenge was building a star tracker to keep the camera trained on the target star system (as it moved with Earth’s rotation) for long exposures. That’s where the arduino, motor, and barndoor base came in. “Aligning the hinge to your hemisphere’s celestial pole allows you to track a star as the plywood “doors” separate at a constant rate,” Schneider writes.
The next challenge was getting the star, not visible to the naked eye, into the camera’s field of view. Schneider used a $20 viewfinder and waypoints, like the Dumbbell Nebula, to locate the system. Then using software that came with his camera, he took a series of automated exposures (50 seconds each) of the star.