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Philosophaie
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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 :
Derivating with respect to time, we get the velocities :
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
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 :
- 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