To replace a deteriorating set of Kitt Peak filters, 3 sets of large BVR glass colour filters were purchased in 1990 for CCD imaging.
The filters consist of cemented stacks of Schott glass, following the following recipe (see also NOAO newsletter 11,12 and 14:
B:1mm BG12 + 2mm BG39 + 1mm GG385
V: 2mm BG39 + 2mm GG495
R: 2mm OG570 + 2mm KG3
An I band filter of the same thickness has been added to all of the Harris sets, this is refereed to as a ``Harris I'', although it was not defined as such by Harris. The recipe is:
I: 4mm RG9
It is thought that
Note that the transmission in B is significantly (about 30%) lower than in Kitt Peak B.