urn:nasa:pds:context:instrument:eso-la_silla.1m52.bcspectrograph 1.4 1.25.0.0 Product_Context 2026-07-07 1.4 Removed duplicate Internal_Reference entries from Reference_List. 2025-12-24 1.3 Adding missing "facility" references. Adding missing "telescope" references. Updated CTLI instrument types. 2025-12-24 1.2 Updated schema version. Adding missing "facility" references. Adding missing "telescope" references. Updated CTLI instrument types. 2025-01-02 1.1 Updated schema version. Adding missing "telescope" references. 2023-03-17 1.0 Initial export from OLAF urn:nasa:pds:context:telescope:eso-la_silla.1m52 instrument_to_telescope urn:nasa:pds:context:facility:observatory.eso-la_silla instrument_to_facility ESO Boller and Chivens Spectrograph Imaging Spectrometer Spectrograph The Boller & Chivens spectrograph at the ESO 1.52m has been equipped with a special dioptric camera for use with the f/15 Cassegrain focus. An order blocking filter assembly is located below the slit jaws to prevent overlapping of unwanted spectral orders. It may hold up to four filters. No deckers are used for observation. The opto-mechanical configuration allows for a fixed angle between the incident and diffracted beam axis of the grating (configuration angle). The grating is mounted in an adjustable rotating cell that permits the choice of the central wavelength and spectral orders (grating angle). The dioptric camera has an efficiency of ~87% between 430 nm and 900 nm and > 78% for wavelengths < 430 nm. The slit assembly consists of two 64mm long polished and aluminized jaws on which the field of view can be seen by the guiding camera. The slit-width is remotely controlled from the observing console in the control room. The slit length is 4.5 arcmin and the scale in the spatial direction is 0.82 arcsec/px. Note: This instrument has been decommissioned in 2002.