Accession No

3310

Brief Description

glass photographic slide showing the spectrum of the star gamma persei, by the Cambridge Observatory, English, 1897

Origin

Cambridge Observatory; Cambridge; England

Maker

Cambridge Observatory

Class

astronomy

Earliest Date

1897

Latest Date

1897

Inscription Date

1897

Material

glass

Dimensions

length 90mm; breadth 40mm

Special Collection

Provenance

Transferred from Institute of Astronomy, University of Cambridge, Cambridge, England, 03/02/1986.

Inscription

C494 1897 Oct. 21 845 (on slide; also further information regarding temperature, star, etc.)

Description Notes

Glass photographic slide showing the spectrum of the star gamma persei. Display card with it gives description of how it was made and what it shows:

‘THE SPECTRUM OF THE STAR GAMMA PERSEI, 1897
‘An original plate, photographed with the Bruce single-prism spectrograph on the Newall 25 inch aperture refractor of the Cambridge Observatory.
‘The spectra above and below are of the emission lines produced by an iron spark; the fainter spectrum of the 3rd magnitude star between them required an exposure of one hour.
‘A measuring microscope was used to determine the very small Doppler displacement of the absorption lines in the spectrum of the star from the ‘rest’ wavelengths of the comparison lines, and hence the radial (line-of-sight) velocity of the star in kilometres per second.
‘It was with such spectra that the first reliable determinations of the motions of stars in space were made in the last years of the 19th century.
‘Institute of Astronomy
‘Plate Archives
‘(D.W. Dewhirst)’

References

Events