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Modified DSLR Imaging

Started by Kevin, 07/09/2011 02:48PM
Posted 07/09/2011 02:48PM Opening Post
What is the preferred method of modifying a DSLR for pure deepsky imaging with a premium APO.

Would simply removing the IR blocking filter work? I've never quite understood taking an IR filter off and replacing it with another UV/IR block.

Is it that you need a UV blocking filter to prevent star bloat or halo's?

I find myself with a spare D70 I could consider for this. I would also like to be consider being able to do wide field deep sky with a wide lens and piggy back stuff.

Kevin
Posted 07/09/2011 06:14PM #1
Hey, Kevin. My understanding is that the stock IR filter cuts off too far up into the red part of spectrum, effectively blocking H-α emissions. The replacement IR/UV filters go deeper into the red, capturing the H-α, but still blocking the longer IR, and short UV. Even your APO will be unable to bring these longest and shortest wavelengths to focus (essentially chromatic aberration). My D50 was modified with a clear glass replacement, and requires the external IR/UV filter for any refractive optics. Used with a purely reflective system (like a Newt with no coma corrector) it could be used without a filter, since reflection does not cause dispersion. Make sense?