Accession Number : ADA543243


Title :   Testing Coordinate Frame Transformations NOVAS vs SOFA


Descriptive Note : Technical note


Corporate Author : NAVAL OBSERVATORY WASHINGTON DC


Personal Author(s) : Monet, Alice ; Kaplan, George ; Harris, William


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA543243


Report Date : 14 JUL 2010


Pagination or Media Count : 26


Abstract : The Standards of Fundamental Astronomy (SOFA) library is the official collection of approved software for positional astronomy, operating under the auspices of International Astronomical Union (IAU) Division 1 (Fundamental Astronomy). Both Fortran and C libraries are available. An international SOFA Reviewing Board manages the collection. Generally, the Naval Observatory Vector Astrometry Software (NOVAS) is independent of SOFA although both software libraries include code that is similar to two International Earth Rotation and Reference System Service (IERS) Fortran modules. NU2000A and iau2000a (Fortran and C, respectively), which evaluate the full 1,365-term IAU 2000A nutation series in NOVAS 3.0, are based on the IERS subroutine NU2000A. EECT2000 and ee_ct, which evaluate the "complementary terms" in the equation of the equinoxes, are based on IERS function EECT2000. The corresponding modules in SOFA are iau_NUT00A, iauNut00a, iau_EECT00, and iauEect00. The document SOFA Tools for Earth Attitude, also known as the "SOFA Cookbook", contains several Fortran examples of the transformation between terrestrial and celestial coordinate systems. This technical note examines how one of those examples plays out in both NOVAS and SOFA.


Descriptors :   *COMPUTER PROGRAMS , *ASTRONOMY , ATTITUDE(INCLINATION) , EARTH(PLANET) , TRANSFORMATIONS , COORDINATES


Subject Categories : ASTRONOMY


Distribution Statement : APPROVED FOR PUBLIC RELEASE