Skip to main content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.


NOVAS—Naval Observatory Vector Astrometry Software

NOVAS info

NOVAS is an integrated package of routines for computing various commonly needed quantities in positional astronomy. Available as Fortran, C, or Python source code.
Current version: 3.1 [Updated March 2011].

Free to DoD and civilian customers - see the NOVAS pages.

Information for DoD Users   (CAC required)

Software Products by Our Colleagues

NavPac and Compact Data

This product is a publication of His Majesty's Nautical Almanac Office (HMNAO) of the United Kingdom. The NavPac software, supplied on CD-ROM, enables navigators to easily compute their position at sea from observations made with a sextant. Compact Data, the book supplied with NavPac, provides simple, efficient and consistent formulae and methods for calculating the positions of the Sun, Moon, navigational planets, and stars, as well as sight reduction using a personal computer or programmable calculator.

Standards Of Fundamental Astronomy (SOFA) Libraries

The International Astronomical Union 's SOFA initiative seeks to promulgate an authoritative set of fundamental-astronomy constants and algorithms. The initiative is managed by an international panel, the SOFA Reviewing Board, appointed through IAU Division 1. The SOFA software libraries are a collection of subprograms, in source-code form, that implement official IAU algorithms for fundamental-astronomy computations. Visit the SOFA Web site for details.

Skip to main content