Re: Station not a silhouette

From: Tom Wagner (sciteach@mchsi.com)
Date: Mon Dec 30 2002 - 22:52:07 EST

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    This may have already have been answered but here goes anyway.
    
    "Magnitude" is a term that is freely used to describe what I will call the
    "luminance" of the moon and satellites. My purpose for asking about the
    Moon's brightness is to help me to try to understand the meaning of
    magnitude and how a person can compare the predicted (and apparent)
    magnitude of a satellite with the Moon's sunlit limb and its dark limb.
    
    I found a listing of the standard magnitude of the full moon in a SeeSat
    Archived message from Richard Keen (richard.keen@kingsmarket.com) dated: Sat
    Mar 18 2000 - 21:46:13 PST.  See, "moon's brightness" at
    http://satobs.org/seesat/Mar-2000/0250.html .
    
    There Richard said that his text listed the full moon as having a value of
    magnitude -12.7.
    
    A response called, "On calculating the magnitude of the Moon"
    came from: Frank E. Reed (FrankEReed@aol.com).
    See: http://satobs.org/seesat/Mar-2000/0267.html
    
    In his response Frank directed us to:
    http://hotel04.ausys.se/pausch/comp/ppcomp.html#15 which states that in
    determining the magnitude of the moon or the planets one must consider,
    "....the apparent diameter of the planet"....and....
    "the phase angle and the elongation." In that article the area is important
    to perceived magnitude yet I found information that describes comparing a
    totally eclipsed moon with stars, i.e. points of light! See:
    http://correio.cc.fc.ul.pt/~apereira/lun_ecl_9709.html
    
    There I read, "Regarding the forthcoming lunar eclipse, we would like to
    encourage observers to actually attempt estimating the moon's total visual
    magnitude during totality by using reversed binoculars. The brightness of
    the moon as viewed through the reversed binoculars is compared to the
    brightness of stars as seen directly with the naked eye."
    
    Sooooo, is there any way to compare the numerical text "magnitude" of the
    sunlit or shaded part of the moon with the predicted "magnitude" of a
    satellite?
    
    Thanks,
    
    Tom
    Iowa
    
    
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