The Huntsman Telescope

TL;DR

The Huntsman Telescope, based on the Dragonfly design, uses multiple telephoto lenses for low surface brightness imaging and exoplanet detection, demonstrating high-precision photometry and minimal flat-fielding limitations.

Contribution

This paper introduces the Huntsman Telescope's design, analyzes flat fielding uncertainties, and presents early results on exoplanet transient detection capabilities.

Findings

Flat fielding uncertainty is around 0.1%, not limiting low surface brightness detection.

Achieved approximately 0.4% photometric precision with a single defocused lens.

Systematic uncertainties are a key focus for high-precision exoplanet imaging.

Abstract

The Huntsman Telescope, located at Siding Spring Observatory in Australia, is a system of ten telephoto Canon lenses designed for low surface brightness imaging in the Southern sky. Based upon the Dragonfly Telephoto Array, the refractive lens-based system provides an obstruction free optical path, which reduces the number of scattering surfaces and allows easier access to lower surface brightness levels. In this proceeding, we present an analysis of the impact of flat fielding uncertainty on the limiting low surface brightness levels. We show that a fairly standard set of flat-field data can be well-characterised to a $\sim0.1\%$ level. This corresponds to a 5-$\sigma$ lower limit of $\sim33$ magnitude per arcsecond$^2$, which means that flat fielding is not likely going to set Huntsman's low surface brightness limit. We also present early results of an exoplanet transient mode for Huntsman where all lenses work together to detect subtle variations in the luminosity of relatively bright $V=8-12$ magnitude stars. High-precision exoplanet imaging is ultimately limited by systematic uncertainties, so we anticipate multiple lenses will help to mitigate issues related to pixel-to-pixel and intra-pixel sensitivity variations. Our initial results show we can easily get $\sim0.4\%$ photometric precision with a single, defocused lens.