Paper, 'Preliminary note on photographs of the spectrum of the nebula in Orion' by J [Joseph] Norman Lockyer

Description

Lockyer writes: 'In other communications to the Society, I have shown that the chief nebula line coincides absolutely in position with the remnant of the fluting seen in the flame of burning magnesium near λ 500, with the highest dispersion we could command at South Kensington. Attempts have recently been made, therefore, with the 30-inch reflector at Westgate-on-Sea, to obtain photographs of the spectrum of the nebula, using magnesium as the term of comparison. The objects sought were, primarily, to determine whether there was a line in the nebula corresponding with one of the lines of the magnesium triplet about λ 373, and to obtain as complete a photographic record as possible of, the spectrum between this triplet and λ 500. With this view, Mawson’s instantaneous plates were used, these having been found to be fairly sensitive to the green. The exposures have been carried up to four hours, and five photographs have already been taken, some of them with shorter exposures than that named, in consequence of the sky becoming clouded or irregularities in the driving clock, which is not yet completely finished.'

Annotations in pencil and ink. Note on front reads 'Copy 14/2/90'.

Subject: Astronomy / Spectroscopy

Received and read 13 February 1890.

A version of this paper was published in volume 48 of the Proceedings of the Royal Society as 'Preliminary note on photographs of the spectrum of the nebula in Orion'.

Reference number

PP/16/18

Earliest possible date

1890

Physical description

Ink and graphite pencil on paper

Page extent

5 pages

Format

Manuscript