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Naval Observatory Vector Astrometry Subroutines

Version : 2.0.1
Author(s) : Astronomical Applications Dept. U.S. Naval Observatory
License : GPL
Website :

Disk space required for installation is 2.93 Mb

The following printable documents will be installed :


The Naval Observatory Vector Astrometry Subroutines, NOVAS, is an
integrated package of source-code modules for computing a wide variety
of common astrometric quantities and transformations. The package can
provide, in one function call, the instantaneous coordinates
(apparent, topocentric, or astrometric place) of any star or planet.
At a lower level, NOVAS also provides general astrometric utility
transformations, such as those for precession, nutation, aberration,
parallax, and the gravitational deflection of light. The computations
are highly precise. The NOVAS algorithms are, in fact, virtually
identical to those now used in the production of The Astronomical
Almanac. NOVAS is easy-to-use and can be incorporated into data
reduction programs, telescope control systems, and simulations.

NOVAS-C uses, as input, astrometric reference data that is
expressed in the International Astronomical Union (IAU) J2000.0
system. In particular, NOVAS-C 2.0 supports (but is not limited to)
data that conforms to the International Celestial Reference System
(ICRS), adopted by the IAU in 1996. ICRS-compatible data includes the
Hipparcos and Tycho Catalogues, the ACT Reference Catalog, the
International Celestial Reference Frame (ICRF), the Jet Propulsion
Laboratory's DE405 planetary ephemeris, and Earth orientation
measurements from the International Earth Rotation Service (IERS). The
list of ICRS-compatible data of various types is continually
expanding. NOVAS-C can also be used with data conforming to the FK5

Effective use of NOVAS-C requires some background in positional
astronomy and considerable programming experience. Please read the
accompanying documentation (in file novasguide.pdf) before attempting
to use the software.

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