Astronomy Photographers have been modifying their DSLRs in a few different ways since they came out. There is a huge difference in sensitivity.


Some only modify the IR/UV filters while other modify like you want making it a monochrome camera. But I believe there is more to it than just removing or replacing the filters, and it's not cheap unless you're brave enough to do it yourself. You can also have it modified so you can use various clip-in filters.