Astronomical spectroscopy in the last four decades: survival of the fittest

Abstract

Spectroscopic astronomical instrumentation has much evolved in the last 40 years. Long-slit grating spectrographs with a photographic plate as the detector working in the 0.3-1 µm range were prevalent up to the early 1970s. The replacement of photographic plates by two-dimensional digital detectors provided gains in sensitivity of two orders of magnitude and much better photometric and radial velocity precision, and opened the 1 to 25 µm infrared domain. Another gain in speed by up to two orders of magnitude was then obtained through the development of various spectroscopic systems, each optimized for a subset of astronomical objects. This development was underpinned by a number of technological advances, in particular the development of automatic data reduction pipelines using sophisticated algorithms. With ever larger and more complex instrument systems for the present 8-10 m diameter telescopes-and soon even more for the next generation of Extremely Large Telescopes, the development of an instrument is now a big enterprise, ranging all the way from long-term enabling technology efforts to management of large teams for construction and deployment over typically 7-8 years.