IMCCE CNRS Observatoire de Besancon SYRTE
INPOP08. a 4-D planetary ephemeris

Reference

A. Fienga, J. Laskar, T. Morlay, H. Manche, P. Kuchynka, C. Leponcin-Lafitte, M. Gastineau and L. Somenzi : 2009,
INPOP08, a 4-D planetary ephemeris:
From asteroid modelisation and time-scale computations to ESA Mars Express and Venus Express contributions.
Astronomy & Astrophysics, 507, pp. 1675-1686
preprint : PDF file

Data used to built INPOP ephemerides are available on the APDB data base.

Solutions

The orbital solutions of the Sun, the eight planets, the dwarf planet Pluto and the Moon, the libration of the Moon and the time scale transformation TT-TDB are available as binary or text data files.
The binary and text data files provide the rectangular coordinates (x,y,z) in kilometers of the bodies with respect to the International Celestial Reference Frame (ICRF). The librations are given in radians. The time scale transformation TT-TDB is given in seconds for the files including it.

File format

These INPOP08 ephemeris files are provided in three file formats


Binary files

These INPOP08 ephemeris files extends the internal format of the binary JPL DExxx ephemeris files (http://ssd.jpl.nasa.gov/?ephemerides) by including the time scale transformation TT-TDB : the coordinates in the data files are expressed as the coefficients of the Chebychev polynomials. These INPOP08 ephemeris files don't include the coefficients for the nutation.

Usage

These files can't be read using the older programs based on the "testeph.f" program. These files must be read with the CALCEPH Library which provides a compatible C and Fortran Application Programming Interface.

Binary files including the time scale transformation TT-TDB - release INPOP08A

time period
(years from J2000)
files
-100 to +100 binary file (18 Mbytes)
-1000 to +1000 binary file (178 Mbytes)


Text files

These INPOP08 ephemeris files are encoded as plain text files : the coordinates in the ascii data files are expressed as the coefficients of the Chebychev polynomials. These INPOP08 ephemeris files don't include the coefficients for the nutation but they include the time scale transformation TT-TDB.
The file format of these files are described in the following document. The exponent letter of the real numbers is 'D' (instead of 'E').

Text files including the time scale transformation TT-TDB - release INPOP08A

time period
(years from J2000)
files
-100 to +100 binary file (64 Mbytes)
-1000 to +1000 binary file (642 Mbytes)


Binary files compatible with the JPL DExxx ephemeris file format (without the time scale transformation TT-TDB)

These INPOP08 ephemeris files use the same internal format as the binary JPL DExxx ephemeris files (http://ssd.jpl.nasa.gov/?ephemerides) : the coordinates in the data files are expressed as the coefficients of the Chebychev polynomials. These INPOP08 ephemeris files don't include the coefficients for the nutation and the time scale transformation TT-TDB. So these files could be read with the same programs (such as the JPL software package) which read the binary JPL ephemeris files.
The internal format is described in the paper :
David Hoffman : 1998,
A Set of C Utility Programs for Processing JPL Ephemeris Data,
ftp://ssd.jpl.nasa.gov/pub/eph/export/C-versions/hoffman/EphemUtilVer0.1.tar

Due to the problem of the endianess in the computer (order in which integers are stored as bytes in computer memory), the binary files are available into two formats :

The ascii header files are provided to show the content of the two first records of the binary ephemeris files. The file format of these ascii files is the same as described in (Hoffman, 1998).

Usage

To use these data files instead of the JPL ephemeris files, you only have to change the name of the files in your software program.
If you use a program based on the "testeph.f" program from the JPL, then you may have to set the variable NRECL (and KSIZE if you don't use the subroutine FSIZER2). The prefered method is to read the beginning of the first record and then to compute the length of the records (same as KSIZE) with the libration's triplet (which contains the location, order and time-coverage of Chebychev polynomial).

We provide the open-source CALCEPH Library, which provides a compatible C and Fortran Application Programming Interface. This library avoids the problems with the variables (NRECL and KSIZE ) and the endianess. It supports the access to the multiple ephemeris files at the same time.

Binary data files compatible with the JPL DExxx ephemeris file format - release INPOP08A

time period
(years from J2000)
little-endian files
(Intel or AMD x86, x86_64, IA64 or Alpha processors)
big-endian files
(Motorola PowerPC, IBM Power or Sparc processors)
value of KSIZE
(for the program "testeph.f")
ascii header files
(for information)
-100 to +100 binary file (17 Mbytes) binary file (17 Mbytes) 1876 ascii file
-1000 to +1000 binary file (168 Mbytes) binary file (168 Mbytes) 1876 ascii file


Contact

For all comments concerning these pages, contact the authors : inpop@imcce.fr.
In order to be informed of further evolution of this site developments, please send an email of interest to inpop@imcce.fr

Last revision : 6 august 2010


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