Exoplanet High Resolution Spectrograph

This project is to realise the so-called EXOhSPEC prototype spectrograph (Exoplanet high resolution spectrograph). It will be entirely built from catalogue components but will utilise technologies not deployed in astronomical spectrographs. EXOhSPEC will be tested on the Sun and local stars both in the laboratory, on local automated telescope as well as with telescopes in the Canaries and Thailand. A version is destined for delivery to the Thai National Telescope. It is intended to have the fewest possible optical surfaces for a high resolution spectrograph and its efficiency and small size will make it a highly attractive for further development. Among several novel developments that we introduce is active metrology which enables us to construct a small athermal spectrograph from off-the-shelf parts. The long-term aim of the project is to be able to build a prototype to significantly extend the reach of precision radial velocities to higher precisions and efficiencies enabling for example a space-based radial velocity instrument. A paper describing early results and laying out future steps for the project is available (Jones et al., 2021) along with software to enable iteration through a number of designs.