2026/07/02 by Matteo Ferro, Matteo Genoni, Henri M. J. Boffin +19
Engineering · Physics and Astronomy · #Advanced Frequency and Time Standards #Ionosphere and magnetosphere dynamics #Photocathodes and Microchannel Plates #astro-ph.IM
paper · pdf · doi:10.1117/12.3103649
15 pages, 12 figures, SPIE proceedings paper (SPIE Astronomical Telescopes + Instrumentation 2026)
openalex publication_date 2026/07/02 · openalex created_date 2026/07/03 · openalex updated_date 2026/07/29 · arxiv created 2026/07/31 · arxiv updated 2026/08/04
We present a comprehensive Exposure Time Calculator (ETC) developed for the Wide-field Spectroscopic Telescope (WST) concept. The WST, currently in its conceptual phase, is designed as a next-generation large spectroscopic survey facility featuring three complementary observing modes: an Integral Field Spectrograph (IFS) covering 370-930 nm at R of about 4800; a high-resolution Multi-Object Spectrograph (MOS-HR) with four bands at R of about 40000; and a low-resolution Multi-Object Spectrograph (MOS-LR) with four channels at R of about 3800-4900. The ETC simulates the complete photon-propagation path from astronomical source to detector, incorporating wavelength-dependent system throughput (telescope transmission, instrumental optics, detector quantum efficiency), accurate sky background via ESO SkyCalc integration, and a comprehensive noise treatment (photon noise, sky background, read-out noise, dark current). The computational core is implemented as the "pyetcwst" Python library built on the MPDAF framework, supporting multiple target spectral energy distributions (stellar templates, blackbody, power-law, emission lines, and user-uploaded spectra with arbitrary redshift) and spatial morphologies (point sources and Sersic extended profiles). Four operational modes enable flexible exposure-time optimization. Full spectral outputs include wavelength-dependent signal-to-noise ratio (SNR), source and sky photon counts, noise decomposition by component, and simulated extracted spectra. An interactive web interface, together with a REST API and a command-line tool, complete the user experience and enable batch survey-design workflows.