[LargeFormat] RE: IR filters

[Clive Warren]

>Hello Clive,
>
>You can see all the Schott glass filters spectral curves at
>
>http://www.noao.edu/kpno/filters/sgt.html
>
>Here is the exact address for the RG-9:
>
>http://www.noao.edu/kpno/filters/sgt/127_sm.gif
>
>The left part of the curve likes that of RG-715, (or rather 
>"RG-720") except that it doesn't turn toward shorter wavenlenths as 
>the RG-715 does, but keeps the wavenlenght even up to density 5. 
>It's for this reason that RG-9 is suitable for direct IR viewing.
>My photos are not yet available on the net at this time.
>
>Marc

Hello Marc,

Thank you for the URLs and the additional info. on the Schott glass filters.

The only thing that puts me off is the cost!

Hope to get out with a camera this weekend as it is about time I 
dragged myself away from this machine before the summer some to an 
end. Wimbledon has started so it's bound to start raining again soon 
;-)

Judging from the lack of traffic on the list everyone else is out 
there having fun so I'll be joining them.

Cheers,
        Clive