Optical fibres are widely used in professional observatories in order to detach spectrographs from telescopes. The advantages are indisputable but at expenses of a reduction of light flux available to the spectrograph. In amateur astronomy observers are confronted to the practical ways to prepare the fibre link between the telescope to the spectrograph. A careful choice of the type of fibre and a suitable opto-mechanical design are required for each particular case. In addition, their preparation and installation require special tools and skills.
The purposes of our Chapter on Optical Fibres are:
- To enumerate the advantages and drawbacks using optical fibres to detach the spectrograph from the telescope. The astronomer has to evaluate the pros and contras to decide to use an optical fibre according to the observation purposes, instruments available (telescope and spectrograph) and budget restrictions
- To describe the more relevant parameters of fibres like optical transmission and focal ratio degradation. These parameters should define the design of the optics to couple the fibre to both, the telescope and spectrograph
- To recommend the most appropriate fibres for amateur spectroscopy. We revise the standard fibres used for telecommunications and advice the most appropriate fibres available on the market.
- To provide tips and tricks to prepare and evaluate fibre links. We intent to explain the techniques to protect, polish and adapt the fibres with the cheapest components
We hope you will find useful all the information contained in these posts and enjoy doing astronomical spectroscopy!