- Photographs of the spectrum of Nova Persei
1901. From Walter Sidgreaves, S.J., "Nova Persei. February
28 to April 4: Stonyhurst college observatory", ApJ vol. 13 (1901),
278-279, plate 10.
- The Ring Nebula in Lyra. Slitless Spectrogram.
(W. H. Wright) From A.S. Eddington, Stars and Atoms (London,
1942). Picture taken from the on-line
edition published by Eric Hutton (used here with permission).