Example and description of the header for the ascii ephemeris file. Name of the ascii files : - xxx_pos_xxx (position) - xxx_vel_xxx (velocity) Example of the header for the ascii ephemerids file : ----------------------------------------------------- version : 2010.0823 EMB Barycenter equator position km 3 13 16 46872 0 0.0 0 2076569.00 0 2826521.00 0 2076569.00 2076585.00 -0.51646713878001049D+08 +0.18904337998910919D+08 +0.23965838808558852D+06 -0.14433683563893308D+05 -0.74028006867505610D+02 +0.29530723814005357D+01 -0.10426870236794154D-03 -0.40716697498135437D-03 +0.46828451255957283D-04 +0.87515955658569086D-05 -0.36051564205988757D-05 +0.20422748586932890D-06 +0.17555430531501770D-06 Explanation of each record (or line): ------------------------------------- Header first record : self explanatory --------------------- Header Second record : ---------------------- Body values : [Sun, Mercury ...., Neptune, Moon, Libration, TT-TDB ] "Libration" meaning "libration of the Moon" Origin value : [Barycenter, Geocentric] "Barycenter" meaning "BCRS", "Geocentric" meaning "center of the Earth is the origin" Frame value : [equator] meaning ICRF Type values : [position, velocity, angle, ang.vel.] "ang.vel." meaning "angular velocity" unit values : [AU, AU/day, km, km/day, m, m/s, rd, rd/day] "rd" meaning "radian" dimensionality integer number of line per interval of time ( here 3 is for x, y, z or vx, vy, vz, 1 for TT-TDB) order integer number of coefficients for each interval and each scalar quantity notice that order = degree + 1 span real length in days of the standard intervals of each period covered with one expansion N_s integer number of standard intervals of length span in the file 0 integer (unused, always 0) 0.0 real (unused, always 0.0) 0 integer (unused, always 0) Jd_beg days first date of validity of the file in julian days given in two doubles with integral part and then fractional part. Jd_end days last date of validity of the file in julian days given in two doubles with integral part and then fractional part. notice : this is not an independent parameter, but this is useful to test that the date of call is always inside this interval. Body of the file ---------------- Each record contains : - Jd_beg days first date of validity of the record - Jd_end days last date of validity of the record - the n Chebyshev coefficients (n = order) for one scalar component within an interval of length span. There are in total in each file dimensionality*N_s records (or lines) with the coefficients.