Re: Standard Magnitude Calculation

From: Phelps Williams (phelpsw@gmail.com)
Date: Tue Oct 14 2008 - 17:54:34 UTC

  • Next message: Bjoern Gimle@GlocalNet: "Re: Standard Magnitude Calculation"

    It is this radar cross section to standard magnitude conversion that I
    am interested in.  I will look into SkyMap later this evening.
    
    On Tue, Oct 14, 2008 at 1:30 AM, B Gimle @ComHem <b.gimle@comhem.se> wrote:
    > Most standard magnitudes are derived from actual observations, after
    > (approximate) conversion to 90 or 180 degrees phase, probably using
    > ln(1-cos(phase) and 5*log10(range) as correction terms.
    > Also there are different preferences re using max or average magnitude.
    > See http://www.io.com/~mmccants/tles/intrmagdef.html
    > Rob Matson's SkyMap can use the standard magnitude on elset Line0 or in its
    > SKYMAP.DAT file.
    > The SKYMAP.DAT can also contain Radar Cross Sections, which are converted to
    > standard magnitudes internally.
    >
    > From dimensions, surface form and properties "conversion" is very difficult,
    > but I believe that a white sphere of  1 m2 cross-section is +6.4
    >
    > /Björn
    >
    > ----- Original Message -----
    >>
    >> I am interested in how standard magnitude is calculated.  I have been
    >> unable to find information on this exact calculation beyond the fact
    >> that it is based on the surface area of the spacecraft and some
    >> assumptions about the surface properties.
    >>
    >> I cannot find further definition beyond what is mentioned here:
    >> http://www.io.com/~mmccants/tles/mccdesc.html
    >
    >
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