Unless otherwise specified the effects of an f
4.5 converging beam of light
has been taken into account and the central wavelength duly reddened. A
correction of +2 Angstroms has also been made to correct the central
wavelength for operation at +10 degrees Celsius on the assumption that the
filters will be made, tested and specified at +20 degrees Celsius.
In all cases the thickness of the filter including blocking filters should not
exceed 9mm and should be the same for all filters wherever possible.
Blocking in all cases should
be 3000-12000 Angstroms and the tolerance on the central wavelength should be
3 Angstroms. The tolerance on the dimensions of each filter
should be 
0.5mm. Filters should be free from pinholes greater than
0.03mm diameter in the central 25mm diameter circle and free from pinholes
greater than 0.1mm diameter elsewhere.
Table: Summary of 50 mm filters for CCD imaging
Table: Summary of 50 mm filters for CCD imaging (continued)