Gaussian Telescope Aperture Improves Contrast

Changing the aperture of a telescope has allowed researchers from Pennsylvania State University in University Park to find a star previously hidden by a brighter star.

The team, led by Jian Ge, mounted a metal disc with 12 Gaussian-shaped holes onto a 100-in. telescope at Mount Wilson Observatory in Pasadena, Calif. The scientists combined it with adaptive optics to correct atmospheric turbulence and with a 256 X 256-pixel infrared camera, which they designed, to detect cool objects. The disc, called a pupil mask, minimized light diffracted from the bright star, producing a dark null along its symmetry axis. While this produced contrast comparable to conventional methods, it has the potential to provide 100 times more contrast if adaptive optics are improved to minimize scattered light. The mask is also cheaper and faster than other techniques and can transform most telescopes into high-contrast instruments. Results were published in the June 20 issue of The Astrophysical Journal and the July issue of The Astronomical Journal.