Re: Brightness relation to phase angle

From: Thomas A. Troszak (
Date: Fri Feb 09 2001 - 07:05:42 PST

  • Next message: Russell: "FEB9.OBS"

    Dear Robert, 
    I know you are busy, so here is the condensed version:
    My experiments indicate that the size and brightness of a reflection of
    the Sun from a shiny sphere is a function of the radius of the
    reflecting sphere, and the OBSERVER's distance to the reflecting sphere,
    exactly as you said.  
    But here is the interesting part:  The phase angle DOES appear to affect
    the reflection, but the wacky bit is that the reflection gets BIGGER as
    the angle gets shallower.  Meaning, with the sun at my back, the
    reflection is a small dot near the center of the sphere as described. 
    Turning around, with the Sun reflecting off of the sphere, the image
    spreads out into a crescent as it gets nearer the edge (shallower angle)
    and gets brighter.
    My experiment concludes that the phase angle of a reflection DOES affect
    the size, shape and brightness of a reflection from a shiny sphere, but
    in the opposite way than I expected.
    Any comments?
    Tom Troszak, Asheville, NC, USA
    35.601 N, -82.554 W
    Unsubscribe from SeeSat-L by sending a message with 'unsubscribe'
    in the SUBJECT to

    This archive was generated by hypermail 2b29 : Fri Feb 09 2001 - 07:01:42 PST