Boksenberg, Alexander

(1936– ) British astrophysicist: inventor of an image photon counting system (IPCS) of great value in optical astronomy.

Boksenberg studied physics in London, and from the 1960s worked on image-detecting systems for use in space vehicles and ground-based telescopes. For a century, photographic plates or films have been used to accumulate light in faint telescopic images, but the method has disadvantages and electronic detectors (eg CCDs, charge-coupled devices) have been much used. Boksenberg’s method uses a TV camera and image intensifier, whose amplified signals are processed by computer, to give a pixel picture of dots (each due to a photon) which can be both viewed and stored.

In this way, very distant and/or faint objects can be studied in the optical, UV and X-ray range with enhanced sensitivity and accuracy. Boksenberg and others have looked particularly at quasars, aiding understanding of stellar evolution. He became director of the Royal Greenwich Observatory in 1981; the use of CCDs, and especially his IPCS, has revitalized optical astronomy.