Uncooled Microbolometer Arrays for Ground Based Astronomy

TL;DR

This paper presents a low-cost, uncooled microbolometer-based infrared imaging system for ground-based astronomy, demonstrating diffraction-limited imaging, photometric stability, and practical sensitivity for observing celestial events.

Contribution

It introduces a simple, affordable infrared imaging instrument using commercial components, optimized for ground-based astronomical observations with demonstrated capabilities.

Findings

Achieved diffraction-limited imaging with 0.75''/pixel scale.

Demonstrated 10% photometric stability amidst sky variability.

Measured sensitivity limits suitable for lunar eclipse observations.

Abstract

We describe the design and commissioning of a simple prototype, low-cost 10$\mu$m 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 2-m diameter Liverpool Telescope. From observations of bright solar system and stellar sources, we demonstrate a plate scale of 0.75$^{\prime\prime}$ per pixel and confirm the optical design allows diffraction limited imaging. We record a $\sim$ 10$\%$ photometric stability due to sky variability. We measure a $3 \sigma$ sensitivity of $7 \times 10^{3}$ Jy for a single, $\sim$ 0.11 second exposure. This corresponds to a sensitivity limit of $3 \times 10^{2}$ Jy for a 60 second total integration. We present an example science case from observations of the 2019 Jan 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.