Book contents
- Frontmatter
- Contents
- Preface
- Acknowledgements
- 1 The historical development of astronomical spectroscopes and spectrographs
- 2 The theory of spectroscopes and spectrographs
- 3 High resolution spectrographs
- 4 Solar spectrographs and the history of solar spectroscopy
- 5 Objective prism spectrographs
- 6 Ultraviolet and nebular spectroscopy
- 7 Multi-object spectrographs
- 8 Ten pioneering spectrographs of the late twentieth century
- Figure sources and acknowledgements
- Name index
- Subject index
7 - Multi-object spectrographs
Published online by Cambridge University Press: 07 September 2010
- Frontmatter
- Contents
- Preface
- Acknowledgements
- 1 The historical development of astronomical spectroscopes and spectrographs
- 2 The theory of spectroscopes and spectrographs
- 3 High resolution spectrographs
- 4 Solar spectrographs and the history of solar spectroscopy
- 5 Objective prism spectrographs
- 6 Ultraviolet and nebular spectroscopy
- 7 Multi-object spectrographs
- 8 Ten pioneering spectrographs of the late twentieth century
- Figure sources and acknowledgements
- Name index
- Subject index
Summary
LOW RESOLUTION MULTI – OBJECT SPECTROSCOPY
For almost a century since the objective prism spectrograph was first used at Harvard in 1885, this was the only solution available to astronomers for multi-object spectroscopy – the simultaneous recording of the spectra of more than one object. All other astronomical spectroscopy was undertaken sequentially, one object at a time. The limitations of the objective prism caused by overlapping spectra and sky brightness, as well as variable resolving power (dependent on the seeing) have already been discussed.
From about 1980, two new solutions for multi-object spectroscopy, which overcame some of the problems of the objective prism, were introduced. One is the aperture plate combined with a low dispersion element, which is often a combined prism and transmission grating (or ‘grism’ – see Section 2.8). The other is the use of optical fibres. The early history (roughly the first decade) of both these techniques is described here.
APERTURE PLATE MULTI – OBJECT SPECTROSCOPY
The aperture plate was introduced by Harvey Butcher (b. 1947) at Kitt Peak in 1980 as a way of undertaking multi-object spectroscopy of faint objects, all of which lay within the 5 arc minute field of view at the Cassegrain focus of the 4-m Mayall telescope. The aperture plate is a black anodized aluminium sheet in the focal plane, with holes drilled in it, typically with a diameter corresponding to 2.5 arc seconds on the sky.
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- Information
- Astronomical Spectrographs and their History , pp. 184 - 194Publisher: Cambridge University PressPrint publication year: 2009