readme.aa

来自「c源码」· AA 代码 · 共 497 行 · 第 1/2 页

the AA tabulation (an arc second).  The same is true for 1950
FK4 positions taken from the SAO catalogue.  The program agrees
to 0.01" with worked examples presented in the AA. Spot checks
against Apparent Places of Fundamental Stars confirm the mean
place agreement to <0.1".  The APFS uses an older nutation
series, so direct comparison of apparent place is difficult. 
The program incorporates the complete IAU Theory of Nutation
(1980).  Items for the Messier catalogue, messier.cat, are from
either the AA or Sky Catalogue 2000.
   To compute a star's apparent position, its motion since the
catalogue epoch is taken into account as well as the
changes due to precession of the equatorial coordinate system.
Star catalogue files have the following data structure.  Each
star entry occupies one line of ASCII characters.  Numbers can
be in any usual decimal computer format and are separated from
each other by one or more spaces. From the beginning of the
line, the parameters are

Epoch of catalogue coordinates and equinox
Right ascension, hours
Right ascension, minutes
Right ascension, seconds
Declination, degrees
Declination, minutes
Declination, seconds
Proper motion in R.A., s/century
Proper motion in Dec., "/century
Radial velocity, km/s
Distance, parsecs
Visual magnitude
Object name

For example, the line

2000 02 31 48.704  89 15 50.72 19.877 -1.52 -17.0 0.0070 2.02 alUMi(Polaris)

has the following interpretation:

J2000.0      ;Epoch of coordinates, equator, and equinox
2h 31m 48.704s    ;Right Ascension
89deg 15' 50.72"   ;Declination
19.877       ;proper motion in R.A., s/century
-1.52        ;proper motion in Dec., "/century
-17.0        ;radial velocity, km/s
0.007        ;parallax, "
2.02         ;magnitude
alUMi(Polaris)    ;abbreviated name for alpha Ursae Minoris (Polaris)

   Standard abbreviations for 88 constellation names are
expanded into spelled-out form (see constel.c). The program
accepts two types of catalogue coordinates.  If the epoch is
given as 1950, the entire entry is interpreted as an FK4 item. 
The program then automatically converts the data to the FK5
system.  All other epochs are interpreted as being in the FK5
system.
   Note that catalogue (and AA) star coordinates are referred to
the center of the solar system, whereas the program displays the
correct geocentric direction of the object.  The maximum
difference is 0.8" in the case of alpha Centauri.



              Corrections Not Implemented

   Several adjustments are not included.  In general, the Sun is
assumed incorrectly to be at the center of the solar system.
Since the orbit parameters are heliocentric, the main
discrepancy is a tiny change in the annual aberration on the
order of 0.01". The difference between TDT and TDB (Terrestrial
versus Solar System barycentric time) is ignored.  The
topocentric correction for polar motion of the Earth is also
ignored.


              Precession

   Since adoption of the 1976 IAU precession constant, improved
techniques have revealed that a correction of about 0.3" per
century is required.  This program uses the value recommended
by Williams (1994), in part because it is more compatible with
ephemerides computed from DE403 or DE404.  DE403 values are also
used for the obliquity of the equator and the sidereal time.


              Software Notes

A C macro __STDC__, if defined nonzero, will get function
prototypes from the file protos.h.  Some compilers demand the
protoypes but do not define __STDC__.   Some other compilers do
not know what a prototype is.  _MSC_VER is used to recognize
Microsoft C and insert "far" into some declarations; perhaps
other MSDOS compilers would benefit from this too.  On a few
systems "char" is unsigned by default; that may have a bad effect
in the file gplan.c.

- Stephen L. Moshier, November, 1987
[e-mail]
Version 5.4d: October, 1998


              Disc Files

aa.ini         Initialization file - edit this to reflect your location
aa.exe         Executable program for IBM PC MSDOS
messier.cat    Star catalogue of the Messier objects
orbit.cat      Orbit catalogue with example comets, asteroids, etc.
star.cat       Star catalogue of FK5 navigational stars
msvc.zip       Archive containing Microsoft Visual C makefiles
aa_msc6.mak    Old Microsoft C MSDOS make file
aa.rsp         Auxiliary to aa_msc6.mak
makefile       Unix make file
aa.que         Test questions (say "aa <aa.que >test.ans").
aa.ans         Answers to test questions (not necessarily true, but
                what the program says)
aa.c           Main program, keyboard commands
altaz.c        Apparent geocentric to local topocentric place
angles.c       Angles and sides of triangle in three dimensions
annuab.c       Annual aberration
bc4.zip        Archive containing Borland C version 4 makefiles
bc5.zip        Archive containing Borland C version 5 makefiles
aa.prj         Borland Turbo C project file (Thanks to Dominic Scolaro.)
constel.c      Expand constellation name abbreviations
deflec.c       Deflection of light due to Sun's gravity
deltat.c       Ephemeris Time minus Universal Time
diurab.c       Diurnal aberration
diurpx.c       Diurnal parallax
dms.c          Time and date conversions and display
epsiln.c       Obliquity of the ecliptic
fk4fk5.c       FK4 to FK5 star catalogue conversion
kepler.c       Solve hyperbolic, parabolic, or elliptical Keplerian orbits
kfiles.c       System dependent disc file I/O to read catalogues
lightt.c       Correction for light time
lonlat.c       Convert equatorial coordinates to ecliptic polar coordinates
nutate.c       IAU nutation series
precess.c      Precession of the equinox and ecliptic
refrac.c       Correction for atmospheric refraction
rplanet.c      Main reduction subroutine for planets
rstar.c        Main reduction subroutine for stars
sidrlt.c       Sidereal time
sun.c          Main reduction subroutine for the position of the Sun
trnsit.c       Transit of the local meridian
vearth.c       Estimated velocity vector of the Earth
zatan2.c       Quadrant correct arctangent with result from 0 to 2pi
kep.h          Include file for orbit and other data structures
planet.h       Include file for planetary perturbation routines
moon.c         Computation of the Moon's geometric position
domoon.c       Reduction of the Moon's position to apparent place
gplan.c        Computation of planetary positions using mer404.c,...,plu404.c
ear404.c       Ecliptic polar coordinates of the Earth
jup404.c       Ecliptic polar coordinates of Jupiter
mar404.c       Ecliptic polar coordinates of Mars
mer404.c       Ecliptic polar coordinates of Mercury
nep404.c       Ecliptic polar coordinates of Neptune
plu404.c       Ecliptic polar coordinates of Pluto
sat404.c       Ecliptic polar coordinates of Saturn
ura404.c       Ecliptic polar coordinates of Uranus
ven404.c       Ecliptic polar coordinates of Venus
vms.zip        Archive containing VAX VMS makefiles
descrip.mms    VAX make file (MMS)
aa.opt         Auxiliary to descrip.mms

conjunct.c     This is a separate main program that can be used to
               search for events such as new moon dates, solstices, etc.

moonrise.c     Another separate main program, prints a table of lunar 
               rise, transit, and set times.


              References

Nautical Almanac Office, U. S. Naval Observatory, _Astronomical
Almanac for the Year 1986_, U. S. Government Printing Office,
1985.

Nautical Almanac Office, U. S. Naval Observatory, _Almanac for
Computers, 1986_, U. S. Government Printing Office

Meeus, Jean, _Astronomical Formulae for Calculators_, 3rd ed.,
Willmann-Bell, Inc., 1985.

Moulton, F. R., _An Introduction to Celestial Mechanics_, 2nd ed.,
Macmillan, 1914 (Dover reprint, 1970)

Taff, L. G., _Celestial Mechanics, A Computational Guide for the
Practitioner_, Wiley, 1985

Newcomb, S., _Tables of the Four Inner Planets, Astronomical
Papers Prepared for the Use of the American Ephemeris and Nautical
Almanac_, Vol. VI.  Bureau of Equipment, Navy Department,
Washington, 1898

Lieske, J. H., T. Lederle, W. Fricke, and B. Morando,
"Expressions for the Precession Quantities Based upon the IAU
(1976) System of Astronomical Constants,"  Astronomy and
Astrophysics 58, 1-16 (1977).

Laskar, J., "Secular terms of classical planetary theories
using the results of general theory," Astronomy and Astrophysics
157, 59070 (1986).

Bretagnon, P. and G. Francou, "Planetary theories in rectangular
and spherical variables. VSOP87 solutions," Astronomy and
Astrophysics 202, 309-315 (1988).

Bretagnon, P. and Simon, J.-L., _Planetary Programs and Tables
from -4000 to +2800_, Willmann-Bell, 1986

Seidelmann, P. K., et al., "Summary of 1980 IAU Theory of Nutation
(Final Report of the IAU Working Group on Nutation)" in
Transactions of the IAU Vol. XVIII A, Reports on Astronomy,
P. A. Wayman, ed.; D. Reidel Pub. Co., 1982.

"Nutation and the Earth's Rotation", I.A.U. Symposium No. 78,
May, 1977, page 256. I.A.U., 1980.

Woolard, E.W., "A redevelopment of the theory of nutation",
The Astronomical Journal, 58, 1-3 (1953).

Morrison, L. V. and F. R. Stephenson, "Sun and Planetary System"
vol 96,73 eds. W. Fricke, G. Teleki, Reidel, Dordrecht (1982)

Stephenson, F. R., and M. A. Houlden, _Atlas of Historical
Eclipse Maps_, Cambridge U. Press, 1986

Borkowski, K. M., "ELP2000-85 and the Dynamical Time
- Universal Time relation," Astronomy and Astrophysics
205, L8-L10 (1988)

M. Chapront-Touze' and J. Chapront, "ELP2000-85: a semi-analytical
lunar ephemeris adequate for historical times," Astronomy and
Astrophysics 190, 342-352 (1988).

S. L. Moshier, "Comparison of a 7000-year lunar ephemeris with
analytical theory," Astronomy and Astrophysics 262, 613-616 (1992)

J. Chapront, "Representation of planetary ephemerides by frequency
analysis.  Application to the five outer planets,"  Astronomy and
Astrophysics Suppl. Ser. 109, 181-192 (1994)

J. L. Simon, P. Bretagnon, J. Chapront, M. Chapront-Touze', G. Francou,
and J. Laskar, "Numerical Expressions for precession formulae and
mean elements for the Moon and the planets," Astronomy and Astrophysics
282, 663-683 (1994)

James G. Williams, "Contributions to the Earth's obliquity rate,
precession, and nutation,"  Astronomical Journal 108, 711-724 (1994)