Greatest Software Ever Written 4226

On Fri, 18 Aug 2006 10:59:34 -0700, Eugene Miya

I think we're saying the same thing, but to pick nits, I still say there's a typo in Miles' report. Though you are correct that DPTRAJ and buttociated routines were written-developed on the 1108 in the late 1960's and 1970's, the 1108 was long retired by 1995-96 when version DE403 of the ephemeris was produced, so DE403 had to be integrated on a newer implementation of the Sperry UNIVAC 36-bit architecture. An 1100-80 series or a 2200 series performed the integration in 1995-96, hence there is a typo in Miles' 1996 report to the International Astronomical Union. The report should state that DE403 was integrated on an 1100-80 series or a 2200 series, not an 1108. There was no 1108 in existence c. 1995-96 on which to integrate DE403!

For those not familiar with the data product, a DE-series ephemeris is a listing of polynomial coefficients for the state vectors of the major bodies in the solar system as a function of time. A DE-series ephemeris is not source or executable code. It is produced by fitting a model to all available observations of major solar system bodies, and then numerically integrating the solar system model forward (and backward) in time for astronomical and deep space mission support planning. Though the base routines for reading a DE-series ephemeris are provided in Fortran, anyone can write a program in their favorite language to read the coefficients from disk and evaluate the polynomials to determine the state vector of a solar system body at a point in time covered by the ephemeris.

More info here:

-Leif