Instruments

1. The spectrograph (with a Rowland grating) of Lowell observatory. From V. M. Slipher, "The Lowell Spectrograph", ApJ vol. 20 (1904), 1-20.
2. The clock room of the 40 inch refractor at Yerkes observatory. From George E. Hale, "The Yerkes Observatory of the University of Chicago: IV. The Forty-Inch Telescope, Dome and Rising Floor", ApJ vol. 6 (1897), 37-47.
3. A double astrograph with 15 cm aperture and 150 cm focal length objectives, optics by Zeiss and mechanics by Heyde. From Östen Bergstrand, Études sur la distribution de la lumière dans la couronne solaire (L'Éclipse totale de soleil des 20-21 août 1914, IIème partie no. 2) (Stockholm, 1919), figure 1.
4. Star spectroscope by Secchi. From Julius Scheiner, Die Spektralanalyse der Gestirne (Leipzig, 1890), fig. 21.
5. Norman Lockyer's spectroscope, used for observing the spectra of prominences outside of eclipse. From H. Schellen, Spectrum Analysis in its Application to Terrestrial Substances, and the Physical Constitution of the Heavenly Bodies (London, 1872), fig. 135.
6. Spectrograph at the Uppsala observatory. Illustrating the mosaic character of many astronomical instruments, the optics for this instrument was constructed by Steinheil, while the mechanical parts were constructed by Sörensen, instrumentmaker at the Royal Swedish Academy of Sciences. The spectrograph was ordered by Nils Dunér, and was finished by 1897. Photograph by Gustav Holmberg, October 1994. © Gustav Holmberg 1994.
7. Zenith telescope by Warner and Swasey. From "Telescope", Encyclopaedia Britannica, 11th edition (1910-1911).
8. Stellar photometer attached to the 40-inch Yerkes telescope. From J.A. Parkhurst, "Determination of the wedge constant of a stellar photometer", ApJ vol. 13 (1901), 249-259, plate 7.
9. Large Telescope on Trunnion Turn-Table, by James Nasmyth From James Nasmyth, Autobiography edited by Samuel Smiles. Picture taken from the on-line edition published by Eric Hutton (used here with permission). © Eric Hutton 1995.
10. Solar eclipse camera used by Bernhard Hasselberg (right) and the Royal Academy of Sciences' expedition to the total solar eclipse of August 21 1914, stationed near Sollefteå. The instrument had a focal length of 20 meters and used plates measuring 0.7 x 0.7 and 0.5 x 0.5 meters, exposed in the hut at left. To the right is the lens and mirror arrangement. Picture from Hasselberg's archive at the Uppsala University Library.
11. Solar eclipse camera (detail). This is the front end of Hasselberg's camera. Note the telephone used for communicating with personnel at the other end of the instrument. Picture from Hasselberg's archive at the Uppsala University Library.