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Old 19-09-2011, 06:59 AM
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sheeny (Al)
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Join Date: Jun 2005
Location: Oberon NSW
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Thanks Mike.

Quote:
Originally Posted by MLyons View Post
Great images Al,
In the equipment list, you mention a B1200........what be a B1200?
Martin
G'Day Martin,

The B1200 is a Lunt blocking filter. You need 2 things to do Ha viewing or imaging: a Ha Etalon at the front of the scope (SM40) and then a blocking filter (B1200 in my case but Coronado make when as well). The etalon uses resonance between two almost opaque surfaces to build up enough energy to pass through. Of course there can be many resonant frequencies of light. The blocking filter picks out the frequency peak at Ha and blocks the rest.

Al.
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