The use of a cascade intensifier in coudé spectroscopy.

An image intensifier system centered round a four-stage cascade intensifier, EMI type 9694, is described, the image being recorded by a moving plate camera. Astronomical observations were made on the coudé spectrograph of a 30-in. (76-cm) telescope; the dispersion in the blue was 3 A mm(-1). The system was found to be capable of spectrophotometry, the limiting stellar magnitude being 9, and showed considerable gains over alternative techniques in high time resolution observations.