Moded Canon 60D wavelength response

[bojan]

Last week I obtained ASCAR C2 duo band filter, and tried it on NGC 1763..
There is plenty of G & B (as expected), but very little R...
My modded 60D has the first filter (with shaker) left in place, and I know it cuts IR quite sharply (compared to my modded 450D).
So I suspect this could be the reason for lack if R in my test image..

Does anybody have the similar experience? I tried to google some info on the subject (like response curves of 60D filters) but the results are scarce and inconclusive..

[Osbojo]

Found this and thought it might be of assistance:
https://kolarivision.com/articles/internal-cut-filter-transmission/

[bojan]

Hi John,
Yes, I think I saw that page a long time ago..
However it is not quite what I need, Canon (and others) have two filters, and this is the response of both filters in place, while I need responses od individual filters, especially the first one (which looks transparent, but it also IR cut, and it seems it affects Sii line at 672 nm).
Anyway, I bookmarked this page, just in case - it could be useful in the future :-)
Thanks again for the effort!