High-speed imaging system to detect stellar occultations by Kuiper belt and Oort cloud objects

Abstract

The existence of kilometer size objects in the Oort cloud has been conjectured but not observed as these objects are too small and too far away to be detected by reflected sunlight with current telescopes. However, these objects could be detected by serendipitous occultations of stars. We outline a pilot study for a planned occultation survey that will mount high frame-rate sCMOS cameras in the otherwise unused areas in the focal planes of large, ground-based telescopes. Because gigabytes of imaging data are produced every second, making storage of the imaging impractical for long-term observing campaigns, the image processing must be done in real time. We describe a data system that processes up to 330 frames/s of 3200×3200 images in real time and a procedure to analyze the recorded photometry for candidate occultation events by outer solar system objects. Although we did not detect any occultations, we describe successfully trialing our system taking continuous data on 7 nights of sCMOS observations of nearby open clusters with the 2.1 m telescope at McDonald Observatory, Texas.