New telescope designs suitable for massively-multiplexed spectroscopy

TL;DR

This paper introduces two innovative telescope designs optimized for massively-multiplexed spectroscopy, enabling large field-of-view observations with high multiplexing capabilities for advanced astronomical surveys.

Contribution

It presents two novel telescope concepts: a wide-field Cassegrain design and a scalable five-mirror TMA design, tailored for high-multiplex spectroscopy applications.

Findings

Wide field of 2.5 degrees with a 10m primary mirror for fibre feeding.

A 10m TMA telescope with 1.5-degree FOV and 10,000 mini-IFUs capability.

Acceptable performance across 360-1300 nm wavelength range.

Abstract

We present two novel designs for a telescope suitable for massively-multiplexed spectroscopy. The first is a very wide field Cassegrain telescope optimised for fibre feeding. It provides a Field Of View (FOV) of 2.5 degrees diameter with a 10m primary mirror. It is telecentric and works at F/3, optimal for fibre injection. As an option, a gravity invariant focus for the central 10 arc-minutes can be added, to host, for instance, a giant integral field unit (IFU). It has acceptable performance in the 360-1300 nm wavelength range. The second concept is an innovative five mirror telescope design based on a Three Mirror Anastigmatic (TMA) concept. The design provides a large FOV in a convenient, gravity- invariant focal plane, and is scalable to a range of telescope diameters. As specific example, we present a 10m telescope with a 1.5 degree diameter FOV and a relay system that allows simultaneous spectroscopy with 10,000 mini-IFUs over a square degree, or, alternatively a 17.5 square arcminutes giant IFU, by using 240 MUSE-type spectrographs. We stress the importance of developing the telescope and instrument designs for both cases.