S-Cam 3, optical astronomy with a STJ-based imaging spectro-photometer
Publication date: 15 April 2006
Authors: Verhoeve, P., et al.
Journal: Nuclear Instruments and Methods in Physics Research Section A
Copyright: ElsevierS-Cam 3 is the 3rd generation of a cryogenic camera, based on superconducting tunnel junctions (STJs), for ground-based optical astronomy, deployed at the 4.2m William Herschel Telescope (WHT) at La Palma (Spain). It exploits a 10x12 pixel array of Ta/Al STJs, covering a field of view of ~9°x11° on the sky. The wavelength band extends from 330-750nm, with a wavelength resolving power of ~10 at 500nm. The detectors are operated at ~285mK, achieved with a double stage 4He-³He sorption cooler. Each pixel has its own electronic readout chain at room temperature, with a JFET-based charge sensitive preamplifier. The instrument has undergone extensive testing and calibration, followed by the first observation campaign at La Palma in July 2004. This campaign has focused on point sources with time variability, exploiting the instrument's unique combination of spectro-photometry with high time resolution.