Apparent Position of a Star

PDF document and MATLAB script that computes the geocentric and topocentric apparent position of a star.


Updated 26 Jan 2022

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PDF document and MATLAB function named apstar1.m, and a demonstration script, named demo_astar1.m that can be used to determine the apparent geocentric and topocentric coordinates of a star. The source ephemeris for this routine is a JPL binary ephemeris file. These applications use several functions ported to MATLAB from the Fortran version of the NOVAS (Naval Observatory Vector Astrometry Subroutines) source code developed at the United States Naval Observatory (

Cite As

David Eagle (2023). Apparent Position of a Star (, MATLAB Central File Exchange. Retrieved .

MATLAB Release Compatibility
Created with R2019b
Compatible with any release
Platform Compatibility
Windows macOS Linux

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Version Published Release Notes

Updated to use DE440s.bsp JPL ephemeris and N66 version of MICE routines.

Script now computes the leap seconds internally. MICA example output included for comparison.