Re: iridium corridor>observations

From: Paolo Bussola (temoc@libero.it)
Date: Thu May 11 2000 - 04:31:13 PDT

  • Next message: Patrick Curran: "Debris Objects"

    chiayk@pop.singnet.com.sg ha scritto:
    
    > Hi Tom:
    > I did similar but not exact simulated run before. U will see SIMILAR
    > magnitude in +/- 8 km ( or 16 km) corridor from a centre line for very
    
    > bright flares. I am not sure the drop-off is similar for other
    > magnitude. I guesstimage  the visual corridor is around 20-25km from
    > flare centre or (40-50km corridor).
    >
    > >So the question is:What is the normal "corridor of visibility" for
    the
    > Iridium flares as seen by others?
    
    The maximum brightness of an Iridium Flare at the center line depends on
    
    satellite elevation upon the horizon because of its distance from us. An
    
    Iridium Flare at the Zenith point will be at maximum brightness and it
    plots on the ground concentric circles where the flare becomes dimmer as
    we
    go away from center line. In most cases the plots on the ground will be
    concentric ellipses more elongated when the satellite are lower upon the
    
    horizon. So, a "high elevation flare" has a small "corridor" where
    there's
    maximum brightness (60° elevation = +/- 3 km) and a "low elevation
    flare"
    at 10° can be observed at maximum in +/- 15 km. In my page about Iridium
    
    Flares at:
    
    http://www.geocities.com/pbussola/iridium.html
    
    I drawed two graphs about the brightness of 2 flares at 60° and 10° of
    elevation. They are very interesting!
    
    Bye!
    Paolo Bussola
    
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