The Smart Panoramic Optical Sensor Head (SPOSH) - A camera for observations of transient luminous events on planetary night sides

Abstract

We have developed a camera dedicated to imaging faint transient noctilucent phenomena, such as aurorae, electric discharges, meteors or impact flashes, on dark planetary hemispheres. The SPOSH (Smart Panoramic Optical Sensor Head) is equipped with a back-illuminated 1024 x 1024 CCD chip E2V 47-20 with up to 90 % quantum efficiency and has a custom-made optical system of high light-gathering power with a wide field of view of 120 x 120º. Images can be obtained over extended periods at high rate to make monitoring for transient events possible. To reduce the data transmission rate, only those images (or relevant portions thereof) that contain events are returned to the user. The camera has a sophisticated processing unit prepared to interface with a spacecraft system, for image processing and event detection at rates of up to 3 images per second at full resolution. While software optimized for detection of any noctilucent phenomenon can be implemented, the software is currently optimized for the detection of meteors. Over the past years, we have routinely carried out outdoor tests with 4 camera breadboard units that demonstrate that the camera has excellent radiometric performance and geometric resolution at low light levels over its large field of view. The camera has been demonstrated to capture meteors of magnitudes as faint as +6 m moving at angular speeds of 5°/s. The camera opens up new science opportunities for planetary missions.