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Column Names of VSOP87

  1. Mar 13, 2015 #1
    VSOP87 files
    In BDL server, we find one file per planet. Here is an extract of VSOP87 file (for Neptune, version A) :

    VSOP87 VERSION A1 NEPTUNE VARIABLE 1 (XYZ) *T**0 772 TERMS HELIOCENTRIC DYNAMICAL ECLIPTIC AND EQUINOX J2000
    1810 1 0 0 0 0 0 0 0 1 0 0 0 0 -0.00682678287 30.05889926953 30.05890004476 5.31211340029 38.13303563780
    1810 2 0 0 0 0 0 0 0 0 0 0 0 0 0.00000000000 -0.27080164222 0.27080164222 3.14159265359 0.00000000000
    etc...
    1810 771 0 0 0 0 6-16 0 2 0 0 0 0 0.00000001037 -0.00000001976 0.00000002232 2.42169508541 158.37366516480
    1810 772 0 0 0 0 0 0 19-20 0 0 0 0 0.00000000619 0.00000002392 0.00000002471 3.93681150847 658.18966002270

    VSOP87 VERSION A1 NEPTUNE VARIABLE 1 (XYZ) *T**2 102 TERMS HELIOCENTRIC DYNAMICAL ECLIPTIC AND EQUINOX J2000
    1812 1 0 0 0 0 0 0 0 0 0 0 0 0 0.00000000000 0.00005371138 0.00005371138 0.00000000000 0.00000000000
    1812 2 0 0 0 0 0 0 1 -1 0 0 0 0 0.00004488541 0.00000656405 0.00004536283 5.02700751836 36.64856292950
    etc...
    1812 101 0 0 0 0 1 0 0 -1 0 0 0 0 0.00000001759 -0.00000001439 0.00000002273 5.59760233612 491.55792945680
    1812 102 0 0 0 0 0 3 0 -4 0 0 0 0 -0.00000002773 -0.00000000305 0.00000002790 1.90430778774 487.36514376280
    etc..

    The second row is n.
    Rows 3-14 are some combination of A,B,C and X,Y,Z?
    The 15th row is T^alpha
    The Last 4 rows are the Helocentric components?

    Could someone please define the columns: which is the X component of A, Y component of B, Z component of C, etc.

    http://www.astrosurf.com/jephem/astro/ephemeris/et320buildVSOP_en.htm

    The formula to use is :
    et320img01.gif
    Derivating with respect to time, we get the velocities :
    et320img02.gif
    Where :
    - Ai, Bi, Ci are the terms in the BDL file.
    - n is the number of terms given for a planet and a power of time (for example, n = 772 for Neptune, for variable X, T 0).
    - T is in thousands of julian day from JD2000, T = (jd - JD2000) / 365250
     
  2. jcsd
  3. Mar 18, 2015 #2
    Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?
     
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