15.875-inch secondary mirror for 60-inch reflecting telescope
Date: circa 1889
Inventory Number: 1996-1-0684
Classification: Mirror
Maker: Andrew A. Common (1841 - 1903)
User: Edward C. Pickering (1846 - 1919)
User: Harlow Shapley (1885 - 1972)
User: Boyden Station, Bloemfontein ? (founded 1927)
User: Oak Ridge Station ? (1931 - 2005)
User: George R. Agassiz Station, Harvard (1951 - 1982)
User: Harvard College Observatory (founded 1839)
Cultural Region:
Place of Origin:
Dimensions:
mirror: 40.3 x 40.3 x 6.7 cm (15 7/8 x 15 7/8 x 2 5/8 in.)
box: 16 × 45.2 × 46.7 cm (6 5/16 × 17 13/16 × 18 3/8 in.)
Description:
A plane mirror is tied up in paper and cushioned in a wood crate by means of batting made of cotton and string.
Signedunsigned
Inscribedon label on front side of box: 15 7/8-in / Plane Mirror / (by A. A. Common)
in black crayon on box lid: 15 7/8" PLANE / MIRROR
in black crayon on box lid: 15 7/8" PLANE / MIRROR
Historical AttributesThe 60-inch reflector mentioned here is a telescope purchased by the Harvard College Observatory in 1904 from the estate of British astronomer, A. A. Common. Common had made this instrument in England circa 1889.
Edward C. Pickering, the director of the Harvard College Observatory planned to use the 60-inch telescope to extend visual photometry to very faint stars. It turned out to be difficult to outfit the telescope for this purpose. It never resolved stars as well as Pickering had hoped. Moreover, photographic photometry had become a better method than the old visual one. Therefore, the telescope was abandoned for photometery and used for investigations such as the determination of the total intensity of stellar radiation.
In the 1920s, the new director, Harlow Shapley, looked to the Common 60-inch as a tool for his research on the extant of the visible universe. The primary mirror of Common's 60-inch was refigured and a new mounting was constructed by J. W. Fecker. This new 60-inch reflector was sent to the new Boyden Station in South Africa, where it became the largest telescope in service in the southern hemisphere. It is not clear whether the secondary mirror was put into service in South Africa or remained behind.
Edward C. Pickering, the director of the Harvard College Observatory planned to use the 60-inch telescope to extend visual photometry to very faint stars. It turned out to be difficult to outfit the telescope for this purpose. It never resolved stars as well as Pickering had hoped. Moreover, photographic photometry had become a better method than the old visual one. Therefore, the telescope was abandoned for photometery and used for investigations such as the determination of the total intensity of stellar radiation.
In the 1920s, the new director, Harlow Shapley, looked to the Common 60-inch as a tool for his research on the extant of the visible universe. The primary mirror of Common's 60-inch was refigured and a new mounting was constructed by J. W. Fecker. This new 60-inch reflector was sent to the new Boyden Station in South Africa, where it became the largest telescope in service in the southern hemisphere. It is not clear whether the secondary mirror was put into service in South Africa or remained behind.
ProvenanceTransferred to CHSI