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Old 23-10-2012, 06:54 PM
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cometcatcher (Kevin)
<--- Comet Hale-Bopp

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Join Date: Jan 2005
Location: Cloudy Mackay
Posts: 6,213
Hi Justin, I run an unmodified Pentax K-x. The lack of Ha response can be partially made up for by using a good nebula filter like the Astronomik CLS, Baader UHC-s or Lumicon Deep Sky. The Deep Sky and CLS allow about 25 - 30 % of light through so to compensate subs are usually longer by a factor of 3. If you can go long enough the Astronomik UHC should give a huge contrast boost but only lets through 12% of total light so sub length increases by a factor of 6.

These are single shot colour filters that let through only certain spectral lines like OIII, Hb and Ha while blocking skyglow and certain street lights.

They sometimes produce a colour shift but it's easy to balance out in Photoshop.
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