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3.0 Function Overview
3.1 Function List
The following functions are contained in file novas.c:
Entry name
Level
Purpose
app_star
supervisory
Computes the geocentric apparent place of a star, given its J2000.0
catalog mean place.
topo_star
supervisory
Computes the topocentric apparent place of a star, given its J2000.0
catalog mean place and geographic location of observer.
app_planet
supervisory
Computes the geocentric apparent place of a planet or other solar
system body.
topo_planet
supervisory
Computes the topocentric apparent place of a planet or other solar
system body, given the geographic location of observer.
virtual_star
supervisory
Computes the "virtual place" of a star, given its J2000.0 catalog
mean place.
local_star
supervisory
Computes the "local place" of a star, given its J2000.0 catalog mean
place and geographic location of observer.
virtual_planet
supervisory
Computes the "virtual place" of a planet or other solar system body.
local_planet
supervisory
Computes the "local place" of a planet or other solar system body,
given the geographic location of observer.
astro_star
supervisory
Computes the astrometric place of a star, given its J2000.0 catalog
mean place.
astro_planet
supervisory
Computes the astrometric place of a planet or other solar system
body.
mean_star
supervisory
Computes the J2000.0 mean place of a star, given its apparent place.
sidereal_time
supervisory
Computes Greenwich sidereal time, either mean or apparent.
pnsw
supervisory
Transforms arbitrary vector in rotating Earth-fixed (geographic)
system to space-fixed (J2000.0) system.
transform_hip
supervisory
Transforms Hipparcos data at epoch J1991.25 to epoch J2000.0 and
FK5-style units. To be used only for Hipparcos or Tycho stars with
linear space motion.
transform_cat
supervisory
Transforms a star's catalog quantities for a change of epoch and/or
equator and equinox.
equ2hor
supervisory
Transforms apparent equatorial coordinates (right ascension and
declination) to horizon coordinates (zenith distance and azimuth).
Properly accounts for polar motion.
get_earth
utility
Provides barycentric and heliocentric position and velocity of the
Earth at a given time.
spin
utility
Rotates vector by angle equal to sidereal time.
wobble
utility
Adjusts Earth-fixed vector for polar motion.
proper_motion
utility
Updates the position vector of a star to allow for its space motion.
bary_to_geo
utility
Changes origin of coordinates from barycenter of solar system to
center of mass of Earth.
aberration
utility
Adjusts position vector for aberration of light due to motion of Earth.
precession
utility
Applies precession to position vector.
nutate
utility
Applies nutation to position vector.
sun_field
utility
Adjusts position vector for deflection of light by Sun's gravitational
field.
terra
utility
Converts geographic coordinates to geocentric position vector.
vector2radec
utility
Converts position vector to RA and declination.
angle2vector
utility
Converts RA, declination, and distance to a position vector.
