Probably the most reliable guide to vsop2000-p11.dat
is the reference implementation vsop2000.for
.
The input line in question is the first of 5399 k=0 records contributing to $x$.
Those are followed by 5842 k=1 records, 610 k=2 records, and so on up to k=8.
Then $y$ (k=0..8) and $z$ (k=0..7) follow the same pattern.
If I read the Fortran code correctly, the fixed-length (not blank-delimited) record format is:
- Columns 1-7 are an index $i$
- Columns 9-63 are 17 per-body coefficients $b_{kij}$
- Columns 64-72 are three zeroes, ignored
- Columns 73-126 are coefficients $s_{ki}, c_{ki}$ in astronomical units
To compute a position for time $t$ in Julian years since J2000:
- For each body $j$, compute $\theta_j(t) = \dot{\theta}_j t + \theta_j(0)$, where $\dot{\theta}_j$ is the mean motion and $\theta_j(0)$ is the J2000 mean longitude from
vsop2000-exp.txt
- For each record $x_{ki}$, compute $\phi_{ki} = \sum\limits_{j=1}^{17} b_{kij} \theta_j(t)$
- $x = \sum\limits_{k=0}^8 t^k \sum\limits_{i=1}^{n_k} (s_{ki} \sin \phi_{ki} + c_{ki} \cos \phi_{ki})$
- For $y$ and $z$, repeat steps 2 and 3 using the respective sets of records.
This should give you a geocentric Moon position in astronomical units.