(meteorobs) Optimized filters for daytime fireball video capture?

[brodwcjj at integrity.com]

Just brainstorming here:

Could a polarizing filter help cut back some of the day sky light  
intensity while still letting the meteor light through ?

The "blue" of our sky is somewhat polarized and how much so varies  
depending on the area of the sky related to the position of the sun.

Nice thing about polarizers is they are neutral gray  and don't affect  
colors,  (unless specific colors are being polarized,  as is seen in  
crystal microphotography with polarizing filters.)

Just a thought,
Dustin Brown



Message: 4
Date: Mon, 25 May 2009 08:53:13 -0700
From: Ed Majden <epmajden at shaw.ca>
Subject: Re: (meteorobs) Optimized filters for daytime fireball video
         capture?
To: Global Meteor Observing Forum <meteorobs at meteorobs.org>


Hi Thomas:
         I'm not sure if filters would be that effective.  A meteor spectrum
produces emissions from around 340.0 nm (Violet) to around 900.0 nm
( near ir red end).  Selecting a narrow region at the red end will
reduce the output of total radiation produced by a fireball.  If you
go to my web site located at: http://members.shaw.ca/epmajden/
index.htm and look at a spectrum signature you will see what I mean.
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.  A red filter could be used in conjunction  with
this occulting disk to reduce light scatter.  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.
Ed Majden - EMO meteor spectroscopy
Courtenay, B.C.
Canada

On 25-May-09, at 8:13 AM, Thomas Ashcraft wrote:

[Show Quoted Text - 24 lines][Hide Quoted Text]
I am wondering if anyone has experimented with infrared or any other
special optical filters that would be *optimum* for detecting daytime
fireballs? I am wondering if a filter could be made specifically
for the
wavelengths of meteor burn signatures so as to make the meteors
visible
in the midst of a bright daylight sky?

I have used a red filter for my own all-sky video camera and have
tried
to detect daytime fireballs at times of forward scatter radio
receptions
when I knew that fireballs were above in my local daylight sky but I
have been unsuccessful at distinguishing any meteors thus far.
Hence, I
wonder at filter and wavelength optimization.

Has this been worked on?

Thanks in advance for any information or thoughts on the subject.

Thomas Ashcraft  /  New Mexico