VIRUS: an ultracheap 1000-object IFU spectrograph

Abstract

The <b>VI</b>sible <b>R</b>eplicable <b>U</b>ltra-cheap <b>S</b>pectrograph (<b>VIRUS</b>) is a multi-spectrograph made up of 64 individually small and simple “spectrographlets”. It represents a new approach to the design of a highly multiplexed spectrograph, offering the science multiplex advantage of ~10³ objects per exposure, coupled with the engineering multiplex advantage of ~10² spectrographs making up a whole. We argue that this is a cost-effective approach when compared to traditional spectrograph design, where each instrument is essentially a one-off prototype with heavy expenditure on engineering effort. In this paper we describe the conceptual design of VIRUS and compare its cost to conventional spectrographs.