Re: 2000 SG344: asteroid or Saturn rocket?

From: Thomas A. Troszak (tom@bullhammer.com)
Date: Wed Nov 15 2000 - 08:15:46 PST

  • Next message: Tony Beresford: "Nov 15 Obs"

    Matson, Robert wrote:
    
    > Specular spheres indeed have no phase factor.  But shiny
    > spheres and shiny cylinders are always dimmer than their
    > lambertian counterparts of the same reflectivity.
    
    Dear Robert,
    
    I have been following this discussion with great interest. I am
    attempting to understand the specific definition of the term "phase
    factor".
    
    I interpret this like the "phases" of the Moon. When the Sun is at your
    back, the reflected sunlight from the object is greatest, when the
    object is "backlit", the object is all but invisible (neglecting
    reflected light from the earth itself).
    
    It seems that any object will vary in apparent brightness  (whether
    shiny or Lambertian) depending upon the relative angles between the Sun,
    the object and the observer.  Could you clarify for me?
    
    Tom Troszak, Asheville, NC
    35.601 N, -82.554 W
    mailto:tom@bullhammer.com
    
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