In the quest to find life elsewhere in the universe, planetary scientists have detected more than 500 planets outside the solar system, or exoplanets, over the past 15 years. About one-fifth of those were discovered by scanning the sky for any change in a star's brightness that might be caused by a planet passing in front of that star as seen from Earth.
Known as a transit, this event is essentially an eclipse, but instead of blocking an entire celestial body from view, as the Moon does to the sun during a solar eclipse, a transiting planet obscures just a tiny fraction of the light from its parent star. Astronomers use ground-based telescopes to detect these tiny fractions - changes as small as 0.25 percent. Then they try to confirm a planet's existence through careful follow-up observations.
Title: Observing Exoplanet Transits with Digital SLR Cameras Authors: Colin Littlefield
Using a digital single lens reflex (DSLR) camera, I observed a transit of exoplanet HD 189733 in order to determine the feasibility of using these types of cameras for high-precision photometry. The results were scientifically useful, showing that even though the camera is not explicitly designed for scientific applications, it can nevertheless produce high-quality differential photometry.