Use of microprocessors to control a photographic plate measuring machine

A. C. Daly, G S Walker

Research output: Contribution to journalArticlepeer-review


GALAXY is an automatic high-speed photographic plate measuring machine. It is used for measuring the positions of star images on astronomical photographs. Installed in 1972, GALAXY is operated by the Royal Greenwich Observatory as a national facility, for the Science and Engineering Research Council. In recent years the machine has become unreliable and it was decided to rebuild its electronic control system. The measuring machine is controlled by three MC68000 microcomputers operating in parallel. One is responsible for receiving commands from the operator, supplying status information and directing the operation of the machine. Another is dedicated to the high-speed analysis of image pixel data to produce approximate image positions in 'Search' mode. The third controls the operation of the machine and prepares data for the image processor. The three microcomputers are interfaced to a common GALAXY bus under the control of a bus arbitration card; this allows controlled access to the GALAXY bus by each processor. © 1983.

Original languageEnglish
Pages (from-to)123-130
Number of pages8
JournalJournal of Microcomputer Applications
Issue number2
Publication statusPublished - Apr 1983


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