From Wikipedia, the free encyclopedia Naval Observatory Vector Astrometry Subroutines
Naval Observatory Vector Astrometry Subrou-
tines
NOVAS subroutines perform transformations, such as those
caused by precession, nutation and aberration.
Supervisory-level subroutines serve as interfaces to the
basic and utility subroutines to compute the coordinates
of stars or solar system bodies for specific dates and
times.
Developer(s) United States Naval Observatory
Stable C3.0 (C version); F3.0 (Fortran version) /
release December 31, 2009 (C); December 23, 2009 Usage
(FORTRAN)
The NOVAS library can be linked by programs that work
Written in C/Fortran with positions of celestial bodies. For example, "Pocket
Stars", an astronomy software for Smartphone and PDA
Platform Cross-platform (distributed in source code
form) platforms, used the NOVAS as its astrometry engine.[3]
A Python library, PyNOVAS, can be used to call
Type Astrometry NOVAS functions from Python. It uses SWIG to connect
Website http://aa.usno.navy.mil/software/novas/ with the C version of NOVAS.[4]
novas_info.php
The Naval Observatory Vector Astrometry Software
Current status
(NOVAS is a software library for astrometry-related nu-
NOVAS) A new version of NOVAS is being developed.
merical computations. It is developed by the Astronomi-
cal Applications Department, United States Naval Obser-
vatory. Currently, NOVAS has two different editions for C
See also
and Fortran respectively. • United States Naval Observatory
• Astrometry
• SOFA (Astronomy)
Algorithms
The algorithms used by NOVAS are based on vector as-
trometry theories and the IAU resolutions. Instead of us-
References
ing trigonometric formulae from spherical astrometry, [1] ^ Kaplan, George H. "NOVAS".
NOVAS uses the matrix and vector formulation which http://aa.usno.navy.mil/software/novas/
is more rigorous. This version implements the resolu- novas_info.php. Retrieved 2008-08-01.
tions on astronomical reference systems and Earth ro- [2] Kaplan, George. H., et al. (April 1989). "Mean and
tation models passed at the IAU General Assemblies in apparent place computations in the new IAU
1997, 2000, and 2006. According to the Astronomical Ap- system. III - Apparent, topocentric, and astrometric
plications Department, the algorithms used in NOVAS are 97:
places of planets and stars". Astron. J. 97 1197–1210.
identical to those used in the production of the US part of doi:10.1086/115063.
the Astronomical Almanac.[1] [3] Jay Alan Borseth. "Pocket Stars Product Versions
A detailed description of the algorithms can be found (PDA, SP, PC)". Nomad Electronics.
here: Kaplan, et al. (1989) Astron. J. 97 1197.[2]
97, http://www.nomadelectronics.com/Products.aspx.
Retrieved 2008-08-01.
[4] Jaap Spies. "Python & Novas: astrometric software
Structure & celestial navigation". SourceForge.net.
The NOVAS library provides three levels of subroutines http://pynovas.sourceforge.net/. Retrieved
(functions): basic, utility, and supervisory.[1] Basic-level 2008-08-01.
subroutines supply the values of fundamental variables,
such as the nutation angles and the heliocentric positions
of solar system bodies for specific epoches. Utility-level
1
From Wikipedia, the free encyclopedia Naval Observatory Vector Astrometry Subroutines
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