Re: Photographing Iridium Flares - Addendum

From: Bjoern Gimle (b_gimle@algonet.se)
Date: Sun Mar 25 2001 - 09:26:43 PST

  • Next message: Walter Nissen: "quadruple glint from an Iridium"

    Anthony,
    
    >
    > > In daytime, press the shutter release at the predicted second, even if
    > > you don't see it !
    > >
    > > (Of course, if is two seconds late -pointing error?- you could miss the
    > > chance of taking a second shot)
    >
    >   I press the shutter release about 15 seconds earlier on purpose just in
    > case my cellular phone is slightly off. I do ping to the Atomic Clock to
    > calibrate my cellular phone but prefer to add a small safety factor just
    > in case. As you noted, there usually will not be a second chance.  :-)
    >
    do note that these comments were specifically for DAYTIME flashes!
    
    In case you miss it visually, your chance of getting a picture is higher if
    you just trust the predictions - there is no 15 second margin in daylight
    photography!
    
    And if you can't rely to the second on your cellular phone, get a digital
    stopwatch for about 5000 GRD (or a digital wristwatch at less than twice
    that amount?) and set it using a reliable time source (Atomic clock /
    shortwave / TV / telephone service?) before the observation. A count-down
    function is handy, to signal five seconds in advance.
    
    And, by the way, don't bend your neck and stare at the bright sky in
    advance! Just look up five seconds before the flash. And keep the bright sky
    around the Sun hidden behind a house or wall, if possible.
    
    For night-time photographs I find that a short exposure doesn't necessarily
    increase the contrast. There seems to be some threshold effect, so that a
    moderately dark blue ( or green, or grey) sky will make stars and tracks
    stand out better! This of course depends on the light and air pollution in
    your neighbourhood.
    
    
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