Uncooled microbolometer arrays for ground-based astronomy

Abstract

We describe the design and commissioning of a simple prototype, low-cost 10 μm imaging instrument. The system is built using commercially available components including an uncooled microbolometer array as a detector. The incorporation of adjustable germanium reimaging optics rescale the image to the appropriate plate scale for the 2mdiameter Liverpool Telescope. From observations of bright Solar system and stellar sources, we demonstrate a plate scale of 0.75 arcsec per pixel and confirm the optical design allows diffraction limited imaging. We record a ~10 per cent photometric stability due to sky variability. We measure a 3s sensitivity of 7 × 103 Jy for a single, ~0.11 s exposure. This corresponds to a sensitivity limit of 3 × 102 Jy for a 60 s total integration. We present an example science case from observations of the 2019 January total lunar eclipse and show that the system can detect and measure the anomalous cooling rate associated with the features Bellot and Langrenus during eclipse.