A novel pinhole-type camera that substitutes a microelectromechanical systems (MEMS)-based micromirror array for the pinhole has been developed by the Research Center of MEMS Space Telescope at Ewha Womans University (Seoul, Korea) with their collaborators at Seoul National University (Seoul, Korea), Pusan National University (Pusan, Korea), and Moscow State University (Moscow, Russia). The “obscura” telescope is ideal for observing transient luminous objects such as upper atmospheric lightning and gamma-ray bursts. These transient, infrequent events require a wide field of view (FOV) coupled with the ability to study the triggered event in detail once it has occurred.
The obscura telescope combines a wide-FOV pinhole camera or trigger camera with a zoom-in camera. The trigger camera consists of a 90-mm-focal-length mirror and a multi-anode photomultiplier-tube detector for an overall 11.3° FOV. The zoom-in camera uses a MEMS micromirror array to enlarge and rapidly direct the light from a triggered object to another focal-plane detector and has a 2.9° FOV. When looking down from its orbit of 400 km, the telescope is capable of tracking and imaging an object moving at close to the speed of light. The micromirror array consists of small mirrors driven by two-axis electrostatic vertical-comb actuators for rotation in two orthogonal directions to align the event image to the center of the focal-plane array. A prototype of the telescope will be carried on the Russian Tatiana-II satellite to be launched in early 2009. Contact Il H. Park at [email protected].