Details of exhibit
- Exhibition:
- 1907 Fifty-second Annual Exhibition of the Royal Photographic Society of Great Britain
- Exhibit title:
- Photographs of Groups of Sun Spots
- Exhibitor:
- P. H. Cowell
- Section:
- Scientific and Technical Photography and its Application to Processes of Reproduction
- Group Title:
- 514 to 517. Transparencies - Frame III
- Exhibit No.:
- [516]
- Exhibit No. 2:
- [1]
- Description:
- Taken with the Thompson Photographic Reflector of 26 inches aperture, and 22½ feet focal length. In use the aperture is stopped down to 12 inches, and a negative magnifier is employed, giving an image on the photographic plate on a scale of 30 inches to the solar diameter. A and B are positive enlargements on glass from original negatives, A having been enlarged 2'6 diameters, B 2 diameters: that is to say, to scales of 6 feet 6 inches and 5 feet to the solar diameter respectively.
A taken 1907, June 18d. 17h. 15m. G.C.T.
B taken 1907, July 7d. 17h. 10m. G.C.T. - Exhibit type:
- Photograph
- Process:
- [Not Listed] ()
- Award:
- none
