.Andromeda Galaxy (M31), perhaps the first colour astrophoto
Tags: Andromeda, galaxy, M31
The picture alongside is one of the first colour astronomical images—perhaps the first,—made by Bill Miller (1910–1981) on the 11th of August 1958. Bill used the Palomar (now Samuel Oschin) 1.2 m Schmidt Telescope, a telescope very similar to the UK Schmidt telescope at Siding Spring. From the photographic point of view, these telescopes are the equivalent of a reflecting 'lens' working at about F/2.5, with a focal length of about 3 meters. At this time, Bill worked at the Hale Observatories in Pasadena as its scientific photographer, and for many years up to and beyond his retirement in 1975 he was a unique source of knowledge on all aspects of professional astrophotography.
The image shown here was a 120 minute exposure on Super Anscochrome 4 x 5 inch sheet film. Though this transparency film had the then-remarkable speed equivalent to 100 ISO for short exposures in daylight, during the two hour exposure Bill estimated that it dropped to about 8 ISO.
This image was scanned from copy of Bill Miller's 1958 original, kindly loaned to Malin by Dr Robert Brucato, then of Palomar Observatories/Caltech. The film was scanned and adjustments made by Malin to improve the overall colour balance, mainly by increasing the contrast. No differential colour enhancement was used.
Credit: Bill Miller/David Malin
© California Institute of Technology/Bill Miller/David Malin