SPECTROSCOPY
FILTER RESPONSE TESTS
I have used my diffraction grating in a bench set up to test the response of the filters I use for RGB imaging, the IR blocking filter from a B+W quickcam and a Lumicon UHC nebula visual filter. The curves were produced using the program "vspec" The with filter curve was divided by the unfiltered curve to produce the filter response
. The results were plotted in Excel
Conclusions
The RGB filters are effectively transparent at IR
The blue filter also transmits a significant amount of green
The IR block filter also blocks a significant amount of long wavelength visible red
The Lumicon UHC filter has very variable response in red/IR and in fact rejects the H alpha line
