[Laser] Re: street light EME-update

[Glenn Thomas]

At 10:14 AM 7/26/2007, Art wrote:

>Does anyone have any bandpass filters for the sodium lines, 
>especially the 589 nM line? I think they are probably available, but 
>like so much of the parts we need, they are probably horribly expensive.
>
>If I can find a suitable filter, I would be happy to make an attempt 
>to do this from the ground with a photodiode and a 4 inch glass lens.
>
>Regards,
>
>Art

It seems to me that a tunable filter could be made with a slitted box 
and a rotatable prism. Selecting the desired line is then simply a 
matter of finding a sodium light and using it to tune the filter 
(rotate the prism) to the desired wavelength. Presumaqbly the prism 
mount will have a locking nut to keep it tuned...

73 de Glenn wb6w