Status of MEGA-H: An Ultra-Wide-Field Camera for Heliophysics Applications

MEGA-H is a multi-detector, wide-field telescope system that produces ultra-high-resolution, seamless images.  The optical path employs pickoff mirrors that partition the image field onto three individual detectors.  The detectors can be located conveniently apart from each other while preserving the whole FOV and producing a recombined image without any gaps. This architecture enables a scientist to choose the best detector for the task, which may have the good detection properties but insufficient number of pixels, and combine multiple detectors to achieve the desired pixel count. This camera system will initially be mounted behind a wide FOV white light imager and be capable of both wide FOV (10 degrees on diagonal) and high instantaneous field of view (iFOV) (<1.5”) to observe the Sun’s corona.

We describe our progress in assembling and testing the instrument, which is built around COTS telescope optics and camera heads.  Alignment features facilitate fine positioning of the two pickoff mirrors and three camera heads.  Stray light control features prevent ‘sneak path’ rays from falling on the wrong detector. The instrument is designed to work in an airborne environment.  A thermal control subsystem incorporates four thermal zones, to maintain tight focus and alignment under dynamic environmental conditions, while a focus mechanism compensates for large changes in temperature.  The data path is sized to store full-resolution data from three 127 Mpixel cameras, at a rate of 10 GB/s. A real time viewer produces fused images from the three cameras for monitoring of the image acquisition process. 

MEGA-H is sponsored by HESTO,  NASA’s Heliophysics Science and Technology Office.