There are many thousands of photographic star plates in observatories throughout the world, and the number is being added to continually. A major difficulty in making use of the information contained in them lies in the measurement of position, and other data, of star images on the plates, and in bringing the data to a form suitable for computer processing. Manual methods are impossibly slow and laborious for an extended program of measurements, and automatic machines on the market are prohibitively expensive for small observatories with limited resources.