In many of my Windows batch files, I used the following
construct to detect failures:
do_something
if errorlevel 1 (
echo.An error occurred in do_something
exit /b 1
)
I discovered that it is possible for a Windows program
to exit with a negative integer error code.
This causes the above construct to miss the failure
and the batch file blithely continues.
So I have replaced that construct with
do_something || (
echo.An error occurred in do_something
exit /b 1
)
This way, if the command exits with any nonzero error,
we correctly detect it as a failure.
I'm still trying to understand a discrepancy
between ecliptic latitudes calculated in two
different equinoxes: mean equinox of date and
mean J2000 equinox. I keep thinking the two
latitude values should be the same, because they
are measured against an essentially unchanging
ecliptic plane. I understand that ecliptic longitudes
should change as the Earth's equator precesses
by 47 arcseconds per century.
Added new test MoonEcliptic(), that compares
JPL Horizons calculations of the Moon's ecliptic
coordinates relative to equator of date versus
Astronomy_EclipticGeoMoon():
C MoonEcliptic: PASS: count=73050, max lat=1.825 arcsec, max lon=23.462 arcsec.
It is so weird that the maximum latitude discrepancy is less than 2 arcseconds.
Updated MoonVector test to measure maximum errors in addition to RMS errors.
Display distance errors in kilometers instead of dimensionless units.
Defined constant JD_2000 so all my tests that
convert Julian Dates from JPL Horizons can share it.
MoonLatitudes now generates a CSV file for me to study the
ecliptic latitude discrepancy as a function of time.
I can see that it increases away from the year 2000,
and that it is periodic with the Moon's orbit.
This indicates an error in correcting for precession.
Generated new JPL Horizons test data for MoonVector that
covers the years 1900..2100 instead of 1980..2020.
Confirmed that its maximum error is still 1.16 arcsec.
That is error comparing EQJ vectors and ECL vectors.
Created test data using a Windows batch file that downloads
moon phase data from the US Navy Astronomical Applications API,
then converts the resulting JSON into a flat text file.
This has every moon phase for every tenth calendar year
between 1800 and 2100.
I'm keeping the scripts for reference, but I'm checking in
the test data to the repo for repeated use in a unit test
to be created.
