readme.txt

该包是根据DE405提供的国际天球矩形参考框架的基本位置和速度方面的资料

    ------
    vals(nmbr) [d.p.]   : values corresponding to the names in 'nams'


**  CONST  ********  subroutine const(nmv,vlv,sss,nrv)  **********

    Input   (none)
    -----

    Output
    ------
     nmv(nrv) [char*6] : list of nrv names associated with the values in vlv
     vlv(nrv) [d.p.]   : nrv values associated with the names in nmcc
     sss(3) [d.p.]     :
                            sss(1) : starting jed of the ephemeris file
                            sss(2) : ending jed of the ephemeris file
                            sss(3) : number of days covered by each block
                                     of Chebychev coefficients
     nrv [int.]        : number of values in nmv and vlv


**  STATE  ********  subroutine state(jed,list,pv,nut,*)  **********
           
  [This subroutine is identical to that provided in the past; it is still 
   provided to give previous users compatibility; it is not recommended for 
   use by first-time users.]
                                                                     
**  DPLEPH  ********  entry dpleph( tdb2, npl, nctr, pv)  **********

  This entry is identical to "PLEPH", except that the input time, tdb2, is
  doubly-dimensioned for increased precision  [ double precision tdb2(2) ].

                          Any combination of tdb2(1)+tdb2(2) which falls within
                          the time span on the file is a permissible epoch.    
                                                                               
                          For ease in programming, the user may put the entire 
                          date into tdb2(1) and set tdb2(2)=0.        

                          However, for maximum interpolation accuracy, set 
                          tdb2(1) equal to the most recent midnight at or 
                          before interpolation epoch (i.e., xxxxxxx.5d0) and 
                          set tdb2(2) equal to the remaining fractional part 
                          of the day.

                          As an alternative, it may prove convenient to set 
                          tdb2(1) equal to some fixed epoch, such as start of 
                          integration, and set tdb2(2) equal to the remainder 
                          of the desired epoch.

******************************************************************************

CONSTANTS ON THE EPHEMERIS FILE
-------------------------------

The following is a partial list of constants found on the ephemeris file:

  DENUM           Planetary ephemeris number.
  LENUM           Lunar ephemeris number.
  TDATEF, TDATEB  Dates of the Forward and Backward Integrations
  CLIGHT          Speed of light (km/s).
  AU              Number of kilometers per astronomical unit.
  EMRAT           Earth-Moon mass ratio.
  GMi             GM for ith planet [au**3/day**2].
  GMB             GM for the Earth-Moon Barycenter [au**3/day**2].
  GMS             Sun (= k**2) [au**3/day**2].
  X1, ..., ZD9    Initial conditions for the numerical integration,
                  given at "JDEPOC", with respect to "CENTER".
  JDEPOC          Epoch (JED) of initial conditions, normally JED 2440400.5.
  CENTER          Reference center for the initial conditions.
                  (Sun: 11,  Solar System Barycenter: 12)
  RADi            Radius of ith planet [km].
  MA0001...MA0324 GM's of asteroid number 0001 ... 0234 [au**3/day**2].
  PHASE           The phase angle of the moon's rotation.
  LOVENO          The Love Number, k2, for the moon.
  PHI, THT, PSI   Euler angles of the orientation of the lunar mantle.
  OMEGAX, ...     Rotational velocities of the lunar mantle.
  PHIC,THTC,PSIC  Euler angles of the orientation of the lunar core.
  OMGCX, ...      Rotational velocities of the lunar core.

******************************************************************************

ASSISTANCE
----------

If you are really stuck, direct your questions to

*********************************************************
* Dr E Myles Standish; JPL 301-150; Pasadena, CA  91109 *
* TEL: [phone]                   FAX: [phone] *
* Internet:  [e-mail]    [128.149.23.23] *
*********************************************************


I shall try to answer your questions when I'm free from my normal obligations.

However, I'm not in business to supply ephemerides to the outside world;
please realize that I cannot provide customized service to each individual 
user.

   Please include your name, address, phone number and e-mail address.

===============================================================================
         APPENDIX A :  The internal format of the ephemeris files

On the first record of an export binary file or in the "GROUP 1050 of the ascii
"header", there are 3 sets of 13 integers each.  (In the binary version, the
13th of each set is stored away from the first 12.)

The 13 triplets give information about the location, order and time-coverage of
the chebychev polynomials corresponding to the following 13 items:

       Mercury
       Venus
       Earth-Moon barycenter
       Mars 
       Jupiter 
       Saturn
       Uranus
       Neptune
       Pluto
       Moon (geocentric)
       Sun
       Nutations
       Librations

Word (1,i) is the starting location in each data record of the chebychev 
coefficients belonging to the ith item.  Word (2,i) is the number of chebychev 
coefficients per component of the ith item, and Word (3,i) is the number of 
complete sets of coefficients in each data record for the ith item.

Data Records ("GROUP 1070")

These records contain the actual ephemeris data in the form of chebychev 
polynomials.

The first two double precision words in each data record contain

         Julian date of earliest data in record.
         Julian date of latest data in record.

The remaining data are chebychev position coefficients for each component of 
each body on the tape.  The chebychev coefficients for the planets represent 
the solar system barycentric positions of the centers of the planetary systems.

There are three cartesian components (x, y, z), for each of the items #1-11; 
there are two components for the 12th item, nutations : d(psi) and d(epsilon);
there are three components for the 13th item, librations : three euler angles.

Planetary positions are given in kilometers.  DE200 is nominally with respect 
to the mean equator and equinox of J2000, coinciding with the origin of FK5; 
DE403 and DE405 are with respect to the Int Cel Ref Frame.  The nutations and 
librations are given in radians.

===============================================================================

         APPENDIX B : CDrom available from Willmann-Bell


The CD's containing DE200 and DE405 (unix and ascii) and also DE406 (unix only)
are available from Willmann-Bell.  The price is about $25 per disk.

         Willmann-Bell, Inc.
         PO Box 35025
         Richmond, VA 23235
         804-320-7016
         804-272-5920 (Fax)

         http://www.willbell.com/software/jpl.htm

There is an order form that calculates all costs to any country in the world 
on their web page (www.willbell.com).  On the home page there is an icon for 
this. The order form activates security for credit card transactions.  If one
does not want to order over the web, one can print the order form and fax or 
mail it to them.

I now have a limited supply of the ascii version of DE406.  I can lend these 
to those who need the full extended ephemeris and who can not use the unix 
version.

  E M Standish: [e-mail]  (remember to include postal address)

===============================================================================

         APPENDIX C : Corrections to the software on the CDroms

   *****  The Exact Dates Covered by the Ephemeris Files  *****

The dates on the various files do not correspond exactly to those
listed on the face of the disk.  The following are the actual date-
spans covered by the ephemerides:

DE200, ascii : 2312752.5  +1620 JAN 01  to  2513392.5  +2169 MAY 02
DE200, unix  : 2305424.5  +1599 DEC 09  to  2513392.5  +2169 MAY 02
DE405, ascii : 2305424.5  +1599 DEC 09  to  2524592.5  +2199 DEC 31
DE405, unix  : 2305424.5  +1599 DEC 09  to  2525008.5  +2201 FEB 20
DE406, unix  :  625360.5  -3000 FEB 23  to  2816912.5  +3000 MAY 06

For the ascii files, each record covers 32 days, and there is a one
record overlap at the boundary point between files.  I.e., the last
record of one file is identical to the first record of the next.
These records include January 1 of the boundary year.  The program
"asc2eph.f" is designed to handle such overlaps.
------------------------------------------------------------------
                SOFTWARE IMPROVEMENTS                December 2005

Below are improvements to the software on the CDroms.  (The software
on the ftp site ( ftp://ssd.jpl.nasa.gov//pub/eph/export/DE405/) 
has been updated, except for #5 below.)

1)  In "testeph.f" on both CDroms, line 95 should now be

      INTEGER LINE
      DATA LINE/0/

2)  In "testeph.f" on both CDroms, the statement at line 142 was

        DEL=DABS(R(NCOORD)-XI)/(DABS(R(NCOORD))+DABS(XI))

  it should be replaced by:

        DEL=DABS(R(NCOORD)-XI)
        if(ntarg .eq. 15 .and. ncoord .eq. 3)
       * del=del/(0.23d0*(et-2451545.d0))

3)  In "testeph.f" on both CDroms, the statement that was 
    at line 446 should now be

      IF(FIRST) CALL STATE(0.D0,0,0,0.D0)

4)  In "asc2eph.f" on both CDroms, the statement near line 190 was 

       READ (*,'(2I6,3000(/3D26.18))',IOSTAT =IN)
      .      NRW, NCOEFF, (DB(K),K=1,NCOEFF)

  it should replaced by:

    1  READ(*,'(2i6)')NRW,NCOEFF
       if(NRW .EQ. 0) GO TO 1
       READ (*,'(3D26.18)',IOSTAT =IN) (DB(K),K=1,NCOEFF)

5)  In "asc2eph.f" ***>> on the DE406 ascii CDrom only <<*** :

  "3D26.18" in lines 190 and 262 should be replaced by "3D23.15"

6)  In "asc2eph.f" on both CDroms, the 4th from last line was

       READ (*, '(A)') BLANK

  it should now be:

       IF(HEADER .NE. 'GROUP   1070') READ (*, '(A)') BLANK

7)  In "testeph.f", line 910 reads

      T(1)=((PJD(1)-(DBLE(NR-3)*SS(3)+SS(1)))+PJD(4))/SS(3)

    It should be replaced by the following 3 lines:

        tmp1 = DBLE(NR-3)*SS(3) + SS(1)
        tmp2 = PJD(1) - tmp1
        T(1) = (tmp2 + PJD(4))/SS(3)


===============================================================================

         APPENDIX D : Documentation of DE405 and DE406

DE405 Documentation is available from the anonymous ftp site:

   ftp://ssd.jpl.nasa.gov//pub/eph/export/DE405/

The memo is in two forms: 

  1) in a single complete PostScript file, "de405iom.ps", or in

  2) LaTeX file, "de405iom.tex" with the accompanying figures,
     "de405fig1.ps", ... "de405fig8.ps".

The situation is similar for DE403.
===============================================================================

Appendix E : Versions of the software in various languages (from outside sources)

There are a number of contributed versions of the reading routines in
various languages; there are also ephemeris toolkits, binary file
conversions, etc.  These are simply listed here; I have not tested
them.

All responsibility for these software packages resides with their
authors, and all questions pertaining to their use must be directed to
the authors themselves. 

However, I would appreciate hearing of any problems with them.

  E M Standish  ([e-mail])


C-Versions
----------

From Paul Hardy : http://www.ephemeris.com/software.html

The ephemeris.com Software Library, designed to read, write, and
interpolate NASA's JPL ephemeris files (DE200, DE405, DE406, etc.) is
now available online at

     http://www.ephemeris.com/software.html

The software includes standalone programs to read and write ASCII and
binary ephemeris files, interpolate positions, and verify calculations
with pre-computed data from JPL.  The accuracy should match the
accuracy of JPL's software.  The software is written in C, and should
work on any Unix machine.  It will probably run on any other computer
that has the Gnu C compiler.

This software is designed to directly read the binary and ASCII
ephemeris files on JPL's ephemeris CD (available from
http://www.willbell.com), regardless of the machine's byte ordering. 

-----------------

 From Kourosh Arfa-Kaboodvand, Technical University of Darmstadt:
  ([e-mail])

     /pub/ephem/export/C-versions/kourosh  

 From David Hoffman, Johnson Space Center ([e-mail]): 

     /pub/ephem/export/C-versions/hoffman

-----------------

 From Dr. Piotr Dybczynski, Astronomical Observatory, Poznan, Poland
        ([e-mail])

      ftp://ftp.astro.amu.edu.pl, IP: 150.254.66.60


FITS-version
------------

 From Arnold Rots of Harvard-Smithsonian Astrophysical Observatory
   ([e-mail])

    ftp://heasarc.gsfc.nasa.gov/xte/calib_data/clock/bary


Python version
--------------

 From Ray Buvel 

     [e-mail]


Matlab-Based JPL Solar System Ephemeris Toolbox
-----------------------------------------------

 From Brian Sauser, formerly at the Kennedy Space Center

 http://www.openchannelfoundation.org/projects/Matlab-Based_Solar_System_Ephe


UNIX - LINUX Binary Format Conversion
-------------------------------------

 From Thierry Pauwels, Royal Observatory of Belgium:

    [e-mail]
===============================================================================