To replace a deteriorating set of Kitt Peak filters, 3 sets of large (125 mm) BVR glass colour filters were purchased in 1990 for CCD imaging.
The filters consist of cemented stacks of Schott glass, following the recipe below (see also NOAO newsletter 11,12 and 14:
B: 2mm BG12 + 2mm BG39 V: 2mm OG570 + 2mm KG3 R: 1mm BG12 + 2mm BG39 + 1mm GG385
It is thought that
Harris filters are very often used at La Palma, just like Kitt Peak filters, probably because both are on the Kron-Cousins system. Note that the transmission in B is significantly (about 13%) lower than in Kitt Peak B. See Figs 16 and 17 for details of these filters.