ULTRASPEC: a high-speed imaging photometer on the 2.4-m Thai National Telescope

TL;DR

ULTRASPEC is a high-speed, high-sensitivity imaging photometer designed for the 2.4-m Thai National Telescope, enabling rapid observations of astronomical phenomena across a broad wavelength range.

Contribution

This paper introduces ULTRASPEC, a novel high-speed photometer with EMCCD technology, optimized for the Thai National Telescope, and details its design and performance.

Findings

Achieved frame rates of up to 200 Hz

Demonstrated low readout noise with EMCCD

Successfully installed and tested on the TNT

Abstract

ULTRASPEC is a high-speed imaging photometer mounted permanently at one of the Nasmyth focii of the 2.4-m Thai National Telescope (TNT) on Doi Inthanon, Thailand's highest mountain. ULTRASPEC employs a 1024x1024 pixel frame-transfer, electron-multiplying CCD (EMCCD) in conjunction with re-imaging optics to image a field of 7.7'x7.7' at (windowed) frame rates of up to ~200 Hz. The EMCCD has two outputs - a normal output that provides a readout noise of 2.3 e- and an avalanche output that can provide essentially zero readout noise. A six-position filter wheel enables narrow-band and broad-band imaging over the wavelength range 330-1000 nm. The instrument saw first light on the TNT in November 2013 and will be used to study rapid variability in the Universe. In this paper we describe the scientific motivation behind ULTRASPEC, present an outline of its design and report on its measured performance on the TNT.