The B&C Spectrograph is a somewhat evolved version of the classic reflection-optics spectrograph built by Boller & Chivens in the late 1960's. It is capable of moderate-resolution (1--5Å) with good throughput from the atmospheric limit at 3200Å to the near-IR. A provision was implemented in the mid-1970's for multi-order ``echellette'' spectroscopy with a cross-dispersion prism, providing 1--2Å resolution and complete coverage over 3200 -- 8000 for a detector of sufficient size.
Light enters the spectrograph just behind the Cassegrain mounting plate through an aperture assembly which currently accepts one of two reflective slit plates (3). The field around the slit is reflected to a CCD/intensified TV camera for acquisition and guiding (5). Light which passes the slit encounters in order: an electronic shutter for controlling exposure, an order-separating/neutral density filter wheel (7), a below-the-slit viewer for alignment/focusing purposes (5), and then the f/9 off-axis paraboloidal collimator(6). The primary disperser is a standard 102 reflection grating (2) chosen from a wide assortment of available options. Following the grating, the light can be cross-dispersed with a 60 quartz prism (2.3) or sent directly through a manual camera shutter to the spectrograph camera. The camera (10) is an on-axis, semi-solid Schmidt with the corrector element air-spaced from the sphere/secondary/field-flattener. Slit demagnification in the spatial direction is 5.44, for a resulting image scale of 54/mm on the detector (1 = 18m). A CCD dewar (12 and a separate manual) with integral window follows the spectrograph. Calibration lamp illumination is provided via a small mirror inserted above the slit(4).
Appendix A presents four color photographs illustrating the external components of the B&C Spectrograph. A new user should become familiar with these photos! The sides of the spectrograph will be referred to in this manual as being those corresponding to the photos. ``Side 1'' thus refers to the side closest to the control room, with Sides 2 -- 4 corresponding to those seen when walking clockwise around the instrument. For the directionally-oriented, Side 1 refers to the west side, and Side 2 the south side, etc. The letters in square brackets appearing throughout the text refer to the same identifications marked in Appendix A.