I want to make sure I have thorough coverage of exercising
the Jupiter moon calculations before I start tinkering
with truncating the L1.2 models; the eventual goal is
to decrease the code size, especially later for JavaScript.
Only 101 test cases seemed far too small. Now there are 5001.
Increased the time range to cover the years 1931..2068.
Decreased the time step from 100 days to 10 days.
Eliminated all but the geometric data, because I'm testing
code without any light-time or aberration correction.
Updated the README.txt instructions for generating the
JPL Horizons test data.
Output the Jupiter moon model data tables in a tidier format.
Format the amplitudes as fixed-point instead of exponential,
so that the JavaScript minifier will have an easier time
shrinking the data (later, when I get to the JavaScript version).
I translated the L1.2 FORTRAN code into C, and verified
that the calculations match the Stellarium code I modified
to produce EQJ coordinates. I still need to compare against
JPL Horizons data.
Instead of calculating ECL coordinates that I will later
have to convert to EQJ, I re-ran all the JPL Horizons test
data sets for EQJ, and updated the rotation matrix in the
Stellarium sample code to generate EQJ output. I'm still
getting reasonably good fit between the two: the max
error is about 1 part in 5000. I was hoping for better,
so I still wonder if I'm just a tiny bit off in some respect.
Stellarium uses the same L1.2 model for Jupiter's moons that
I am implementing. I wanted to confirm that I have valid test
data that matches something authoritative.
Work in progress.
Generating the data tables for Jupiter's moons, but not using them yet.
Created a stub function Astronomy_JupiterMoons(), but it just
returns invalid vectors. The formulas have not yet been implemented.
I found some FORTRAN code for calculating the positions of Jupiter's
moons. I recorded its origin in README.md. I'm going to experiment
with using it as a basis for doing these calculations in Astronomy Engine.
