The Henrietta Swope Telescope
In 1971, the Carnegie Institution put into operation the first telescope at its new observatory on Cerro Las Campanas in Chile. The Swope Telescope, a 1-meter (40-inch) reflector, is named after a former Carnegie astronomer, Henrietta Swope, a collaborator of Walter Baade and the author of several classic papers, whose generous gift made possible the construction of the telescope.
The Swope telescope was built by the Boller and Chivens Division of the Perkin-Elmer Corp. The optical characteristics are discussed in detail by Bowen and Vaughen (1973, Applied Optics, 12, 1430). The optical design is an f/7 Ritchey-Chrétien in which the radii of curvature of the primary and secondary are equal, thereby achieving a zero Petzval sum and a flat field. Astigmatism is eliminated with a Gascoigne corrector lens. This design achieves a well-corrected field about 3 degrees in diameter. However, to do this it was necessary to use a secondary one-half the diameter of the primary, thereby intercepting 25% of the incident light.
An f/13.5 secondary used for infrared imaging is also available through a top-end "flip".
The following table gives the optical specifications of the f/7 Cassegrain configuration.
|Diameter primary:||1,016 mm|
|Focal length primary:||4,118 mm|
|Focal length Cassegrain:||7,112 mm|
|Diameter hole in primary:||386 mm|
|Diameter secondary:||508 mm|
|Diameter corrector plate:||386 mm|
|Distance between mirrors:||2,384 mm|
|Focal point distance behind surface of primary:||610 mm|
|Radius of curvature of focal surface:||infinity|
|Unvignetted/corrected field of view:||1.92 degrees|
|Vignetting @ 88 arcmin field angle:||5%|