(meteorobs) Optimized filters for daytime fireball video capture?
GeoZay at aol.com
GeoZay at aol.com
Mon May 25 12:29:47 EDT 2009
>> I'm not sure if filters would be that effective. <<
I'm not sure either. Most filters have a filter factor, to compensate for
the loss of light that passes thru for an exposure. I suppose IR filter
also has something like that. Not only IR filters visible light, but a
certain amount of the Infrared as well.
>>You need to reduce the intensity of the Sun first. I have read
somewhere that a driven occulting disk that blocks out the Sun and
tracks it across the sky could be used but this would be complicated
to do I would think.<<
Wouldn't it be better to just set up in a shady spot and not mess with an
occulting disk? You can easily find shady locations with open sky views.
Like when I use to photograph during a full moon, I'd aim the camera in a
direction away from the moons location...The skies will have a little less
light to deal with. The same goes for the sun...aim as far away as you can...I
think that will give you a little more chance. I'm not sure how Infrared
film will do for this case. You might want to give that some thought too.
>> A red filter could be used in conjunction with
this occulting disk to reduce light scatter. <<
I use to use a combination of a red filter and polarizer to slow the
shutter speed into durations of a half minute to a full minute for special
effects time exposures...but that's a long time for a short duration object. I
personally think you're better off doing it at night. This kinda reminds me
of a backward country's space program to land men on the sun...but in order
to succeed, they plan on doing it at night. :O)
geozay
During daylight you may
see a dust trail but this is in the visible region so a filter may
not be effective.. I wonder if one of our professional meteor types
could comment on this.
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