Astronomical spectrographs

Abstract

While the basic components in optical and near-IR spectrographs have not changed significantly in the last 50 years, spectrograph design and fabrication have become significantly more challenging as telescope apertures grow and the performance goals for the spectrographs become more ambitious. In this review, we discuss the basic optical layout and components of modern astronomical spectrographs and review the designs that have been employed for low-resolution (imaging) spectrographs and high-resolution (echelle) spectrographs on modern telescopes. We begin with a discussion of strategies for optical layouts, collimator and camera designs, and the common dispersing elements in use today. Finally, we discuss the challenges associated with extending these designs to the next generation of instruments needed for the extremely large telescopes being undertaken today.