Acknowledgements
Many thanks to Edward Luff, whose help was essential in producing this edition,
and to my wife, Sarah, for understanding and tea.
I also wish to thank my former MSc student Peter Beck. Peter continued to do
research on ultraprecision photometry despite the fact that he was terminally ill.
I always enjoyed his company and our discussions on all aspects of science. This
edition would not have been possible without the work he undertook.
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