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(meteorobs) Filters and visual response...
Hartwig et al -
Greetings! Your conversation woke me up! ;>
> Actually, something like this might be of some use for the Leonids this
> November. Scattered moonlight is the same color as scattered sunlight.
> However, orange isnšt the right color. You want red. The scattering of
> light in the atmosphere is stronger at the blue end, and weaker at the red
> end, so the overall result looks bluish.
>
> There is one problem, however. The dark adapeted eye is nearly not
> red sensitivie (but sensitive at 500nm). Obviously red sensitivity
> is good for CCD and video, but not for visual observers.
I can't seem to find it right at this moment... am in the middle of 'spring
cleaning' my apartment and reorganizing my books and papers... some of which
have not seen daylight since I moved in here... but I do have a copy of a
very interesting article which addresses some of these ideas.
If I recall the details correctly... it's from the chapter on comets in the
book 'Photographing the Solar System' by Don Parker and Charles Capin... and
specifically talks about filter use for both photographing, and observing
comets visually. It is one of the few books I don't own... but I have a
photocopy of the comet chapter.
Comets are a passion of mine, and this particular chapter in the book has an
extremely detailed discussion on counteracting sky conditions with the
judicious use of filters, taking into consideration the sensitivity response
of the human eye. I would strongly recommend those interested to take a
look at the book.
For comets anyway, in twilight conditions with light blue skies, they
recommend a yellow filter... and discuss (if I recall correctly) the
possibility of cyan. The discussion does revolve around comets, per se, not
meteors, but I would expect that the comments would have some possible
applications to meteors.
Regards,
Cathy Hall
Metcalfe, Ontario, Canada
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