A technique for astronomical spectroscopy with a multi-aperture telescope

Abstract

A technique for acquiring spectral line data using a multi-aperture telescope is described. The multi-aperture principle and the criteria which led to the selection of a dispersive spectrometer are discussed. The problem of linking telescope and spectrometer has been solved by incorporating low loss optical fibres and this is also discussed.
The problems of automatic data collection, its manipulation, display and storage presented a major research effort which were largely overcome by the use of cheap, digital micro-computers. To achieve rapid and flexible data handling the i.E.E.E. bus was used as the communication medium between control and data collecting micro-computers.
In particular a non-standard approach was adopted when implementing specialised interrupt handling routines to deal with data communication, an aspect which forms the central theme of this thesis and is described in chapters three to five inclusive.
A discussion relating to data obtained using the system in single fibre mode and to RPCS data obtained at intermediate resolution is presented in chapters six and seven respectively. The former permitted a preliminary determination to be made of both system resolution and the approximate integration times required to undertake a program of stellar emission line work. This is complimentary to that described in the final chapter which discusses the spectra of emission line stars, some of which are accompanied by circumstellar 'shells'. For pre-main sequence stars these shells may ultimately provide conditions favourable for the formation of planetary systems. There are examples of these types of stars to be found in the Northern hemisphere and which are within the detection limit of the system described in this thesis.