Re: [ATM] infrared filters using film

["Lawrence D. Lopez Software Engineer" <lopez@mv.mv.com>]

Good Job George.

I am sorry I wasn't clear in my post.


George Anderson wrote:

>He is using the filter to block all but the infra-red light. This is
>fine for I/R imaging of nightsky objects as he is doing, and if you
>don't mind the low quality of the filter.
>The Thousand Oaks and Coranodo filters are a very different kettle of
>fish. They are intended for solar viewing and are a very narrow bandpass
>filter intended for viewing the sun.
>DO NOT USE COLOUR (or any photographic film) FILM TO VIEW THE SUN!!!!
>With a refractor you will most likely burn your eye in a heartbeat or
>two (the film filter is letting the dangerous I/R pass at high levels),
>with a reflector you will also burn your eye and probably damage your
>secondary while you are trying to figure out why you can't see anything
>through what used to be your good eye. Not that you will care about the
>secondary anymore as your friends will call you cyclops from now on.
>There is a reason that quality filters for solar viewing cost serious
>coin, they are expensive to make. There is no text substitute for what
>the human eye can see.
>
>George Anderson
>Montreal Canada
>
>Clear skies and good health
>
>"Lawrence D. Lopez Software Engineer" wrote:
>  
>
>>My brother sent me this link.
>>Please understand that it does produce pop ups.
>>Basically it says that you can use color film
>>(Kodacolor say) as an infrared filter.
>>
>>http://www.angelfire.com/space2/tgtan/infrared.htm
>>
>>What I was wondering was how imporant is the
>>figure of the surface of such a filter.
>>
>>I've heard of very accurate filters from Zeiss.
>>I've also heard that 1000 oaks filters did not have a good figure
>>and that Coronado did, and that there was some improvement.
>>But these were fill arperture filters.
>>
>>Can anyone shed any light on this ?
>>
>>Does it matter much ?
>>
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>>    
>>
>
>  
>

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