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Old 22-11-2007, 02:32 PM
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okiscopey (Mike)
Rocky Peak Observatory

okiscopey is offline
 
Join Date: Aug 2006
Location: Kandos NSW
Posts: 536
Quote:
Originally Posted by Lee View Post
Ha filter - lets through only a 13nm band of light centred on ... 656.3nm (red light)
UV/IR filters block the non-visible light regions at either end of the visible spectrum (UV below around 380nm, IR above about 750nm)...
You will no doubt get more good advice from others, but one thing to be aware of when trying to comprehend filters is that the term 'filter' can be a bit confusing.

Thus, in Lee's response above, the H-alpha 'filter' lets through H-alpha, but a UV 'filter' blocks UV. The context is usually clear, but if not it's best to use the terms 'blocking filter' (or 'absorption filter') and 'transmission filter'.
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