People might be interested in this reply I got from Don Goldman about the availability of IR filters.
Steve
"Hi, Steve,
You can post this on the ccdastro group if you like.
We discontinued the NIR set due to lack of interest, but, as you say, still get requests for a NIR Luminance, essentially a NIR long-pass filter, so we do stock this filter in all sizes.
Another part of the reason for discontinuing the NIR RGB is that you can do the same thing with 3 of our photometric sloan filters; i' for blue, z_s for green and Y for red. Please see the spectral profiles at:
http://astrodon.com/store/p12/Astrod...n_Filters.html
http://astrodon.com/uploads/3/4/9/0/...2_i5_w345.jpeg
Yes, typical A/R coatings are centered and optimized for green and often there is little A/R out in the NIR. As a result, you can indeed get reflections from the coverslip or chamber window in the NIR. Also, since NIR penetrates the CCD sensor deeper, especially for backthinned CCDs, you can get some weird banding."