read.me

c源码

AA200 reads astronomical ephemerides, in the data format produced by
Jet Propulsion Laboratory, and reduces the barycentric coordinates to
printouts of geocentric and topocentric place.  See readme.aa for
other features of the program that are common to aa200.zip and aa.zip.
In addition to the screen display, AA200 writes a log file "eph.ans" of
apparent positions calculated.

Specific configuration for the DE406, DE405, DE404, DE403, DE245, DE200
and DE102 ephemerides are supplied.  The ephemeris data files
themselves are not supplied (they are on navigator.jpl.nasa.gov).
Alternatively, you can use a CD ROM of DE405 and DE406 purchased from
Willman-Bell publishing company.

There is also a configuration called SSYSTEM to read the tabular
output produced by the numerical integrator ssystem.exe in
"de118i.arc."

Edit kep.h to indicate:

  Your computer system (UNIX, IBMPC, etc.).  If it is not listed,
   you may have to add a new one and edit kepjpl.c to invoke the
   appropriate system I/O header files.

  The floating point format of the ephemeris file and the format
   of your computer.  A conversion from DEC to IEEE is provided.

  Verbosity -- define DEBUG 1 for various extra printouts.

Edit the makefile to indicate the ephemeris (DE245, DE200, DE102,
SSYSTEM, etc.).

For SSYSTEM, edit NINTERP in kepi.c for the desired interpolator
degree.  Maximum precision is obtained by configuring ssystem.exe for
a 1/8 day step size, 12th order integrator and a 1/8 day output
ephemeris, and NINTERP set to 12.  If the output ephemeris has a
larger tabular interval, it might be better to use a smaller value of
NINTERP.

Look in de245.h, de200.h, de102.h, ..., and make sure that rec0 is
initialized correctly to the offset of the first real data record of
the ephemeris file.  If the file is a complete DE200 magtape image, it
will have an 18132-byte header that must be skipped over.  Other files
containing fragments of the ephemeris can be used by setting rec0 to
zero or some other appropriate value.

The file name and directory path of the ephemeris file are
defined in aa.ini, which you can edit with a text editor.  The
program complains and asks for another file name if it cannot
find that one.

Answers from this program using DE200 or de118i.arc should agree
exactly with Astronomical Almanac tabulations from about 1984 onward.
Almanacs prior to 1987, however, are believed to have small systematic
errors, such as a low-precision formula used for gravitational light
deflection.

Note that the DE102 contains no nutation series.  The IAU (1980)
expansion for nutation is used here for both DE102 and DE200.
Newer formulas for precession, nutation, sidereal time, and
deltaT are used for DE403.

See readme.aa for user instructions.

Steve Moshier
[e-mail]
November, 1993  (v5.2)
January, 1995 (v5.4)
Minor update March, 1996.  Checked with MSC, DJGPP, and Linux.
Minor update for DE403 December 1996.
Automated iterative solution for rise, transit, and set times, November 1998
Minor update for Borland compiler, September 1999 (v5.6)

Files:

aaNNN.ini      Startup information, to be edited for your location
de200.dat      Default name of ephemeris data file, defined in aa.ini
kep.h	       System configuration and general definitions
kepi.c         Reads ephemeris file generated by ssystem.exe.
kepjpl.c       Reads the JPL ephemeris file.  Special header
               file configuration may be necessary for your system.
kfiles.c       Uses fopen, fread functions to read aa.ini and
               orbit.cat, star.cat catalogue files.
aa.que         Test questions
aa200.ans      Answers to test questions
aa200.c        Main interactive program
msc.mak        Microsoft C (antique version 5 or 6, not Visual C++) makefile
bc45.zip       Borland C++ version 4.5 project files
msvc5.zip      Microsoft Visual C++ version 5 project files
msvc6.zip      Microsoft Visual C++ version 6 project files
unix.mak       Unix makefile
altaz.c        Topocentric coordinates
angles.c       Sun - object - earth angles and distances
annuab.c       Annual aberration
constel.c      Table of constellation names
cvtdec.c       Digital Equipment Corp (DEC) floating point format
de102.h        Definitions for JPL DE102 ephemeris
de200.h        Definitions for JPL DE200 ephemeris
deNNN.h        Definitions for JPL DEwhatevernumber ephemeris
deflec.c       Light deflection due to the sun's gravity
deltat.c       Ephemeris Time versus Univeral Time
diurab.c       Diurnal aberration
diurpx.c       Diurnal parallax
dms.c          Angle and date conversions
epsiln.c       Obliquity of the ecliptic
fk4fk5.c       FK4 to FK5 catalogue conversion
kepj.c         Kepler's equation
lightt.c       Light time aberration
lonlat.c       Equatorial to ecliptic transformation
messier.cat    Messier catalogue
moonjpl.c      Special printouts for the moon
nutate.c       Nutation
oparams.c      Position and velocity to orbital elements
orbit.cat      Miscellaneous orbital elements
pctomot.c      Utility endian-ness swapper
precess.c      Precession
read.me        This file
readme.aa      More documentation
refrac.c       Atmospheric refraction
revtime.c      Utility to reverse time order of SSYSTEM records.
               Time must be increasing for aa200 to work!
rplanet.c      Reduction of planetary coordinates
rstar.c        Reduction of stellar coordinates
set3.c         Set III corrections for DE102
sidrlt.c       Sidereal time
star.cat       Miscellaneous stars
sun.c          Special printouts for the sun
tdb.c          Compute TDB - TDT
trnsit.c       Transit time, rise and set
vearth.c       Velocity of the earth
zatan2.c       Arctangent
x200.c         Utility to extract time series from JPL ephemeris.
ephs.zip       Ephemeris file to test DE118I configuration