urn:nasa:pds:context:instrument:irtf-maunakea.3m2.cvf 1.3 1.25.0.0 Product_Context urn:nasa:pds:context:instrument:irtf.3m0.cvf 2026-07-07 1.3 Removed duplicate Internal_Reference entries from Reference_List. 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. 2021-12-07 1.0 per RMS, deprecated irtf in favor of irtf-maunakea urn:nasa:pds:context:telescope:irtf-maunakea.3m2 instrument_to_telescope urn:nasa:pds:context:facility:observatory.irtf-maunakea instrument_to_facility Bugayevskiy, L.M., and J.P. Snyder, Map projections: A reference manual, Taylor & Francis, London and Bristol, Pennsylvania, 328 pp., 1995. Circularly Variable Filter Spectrometer Filter Photometer A Circularly Variable Filter (CVF) is an optical filter with a gradually changing wavelength transmission along its circumference. It allows for continuous spectral tuning by simply rotating the filter, making it useful for hyperspectral imaging and spectroscopy.