NOVAS31 Methods 
The NOVAS31 type exposes the following members.
Name  Description  

Aberration 
Corrects position vector for aberration of light. Algorithm includes relativistic terms.


AppPlanet 
Compute the apparent place of a planet or other solar system body.


AppStar 
Computes the apparent place of a star at date 'JdTt', given its catalog mean place, proper motion, parallax, and radial velocity.


AstroPlanet 
Compute the astrometric place of a planet or other solar system body.


AstroStar 
Computes the astrometric place of a star at date 'JdTt', given its catalog mean place, proper motion, parallax, and radial velocity.


Bary2Obs 
Move the origin of coordinates from the barycenter of the solar system to the observer (or the geocenter); i.e., this function accounts for parallax (annual+geocentric or justannual).


CalDate 
This function will compute a date on the Gregorian calendar given the Julian date.


Cel2Ter 
This function rotates a vector from the celestial to the terrestrial system. Specifically, it transforms a vector in the
GCRS (a local spacefixed system) to the ITRS (a rotating earthfixed system) by applying rotations for the GCRStodynamical
frame tie, precession, nutation, Earth rotation, and polar motion.


CelPole 
This function allows for the specification of celestial pole offsets for highprecision applications. Each set of offsets is a correction to the modeled position of the pole for a specific date, derived from observations and published by the IERS.


CioArray 
Calaculate an array of CIO RA values around a given date


CioBasis 
Compute the orthonormal basis vectors of the celestial intermediate system.


CioLocation 
Returns the location of the celestial intermediate origin (CIO) for a given Julian date, as a right ascension


CioRa 
Computes the true right ascension of the celestial intermediate origin (CIO) at a given TT Julian date. This is (equation of the origins).


DeltaT 
Return the value of DeltaT for the given Julian date


Dispose 
Cleans up the NOVAS3 object and releases its open file handle on the JPL planetary ephemeris file


DLight 
Returns the difference in lighttime, for a star, between the barycenter of the solar system and the observer (or the geocenter).


Ecl2EquVec 
Converts an ecliptic position vector to an equatorial position vector.


EeCt 
Compute the "complementary terms" of the equation of the equinoxes consistent with IAU 2000 resolutions.


Ephemeris 
Retrieves the position and velocity of a solar system body from a fundamental ephemeris.


Equ2Ecl 
To convert right ascension and declination to ecliptic longitude and latitude.


Equ2EclVec 
Converts an equatorial position vector to an ecliptic position vector.


Equ2Gal 
Converts ICRS right ascension and declination to galactic longitude and latitude.


Equ2Hor 
Transforms topocentric right ascension and declination to zenith distance and azimuth.


Era 
Returns the value of the Earth Rotation Angle (theta) for a given UT1 Julian date.


ETilt 
Computes quantities related to the orientation of the Earth's rotation axis at Julian date 'JdTdb'.


FrameTie 
To transform a vector from the dynamical reference system to the International Celestial Reference System (ICRS), or vice versa.


FreeLibrary 
Unloads a library DLL


FundArgs 
To compute the fundamental arguments (mean elements) of the Sun and Moon.


Gcrs2Equ 
Converts GCRS right ascension and declination to coordinates with respect to the equator of date (mean or true).


GeoPosVel 
This function computes the geocentric position and velocity of an observer on
the surface of the earth or on a nearearth spacecraft.


GravDef 
Computes the total gravitational deflection of light for the observed object due to the major gravitating bodies in the solar system.


GravVec 
Corrects position vector for the deflection of light in the gravitational field of an arbitrary body.


IraEquinox 
Compute the intermediate right ascension of the equinox at the input Julian date


JulianDate 
Compute the Julian date for a given calendar date (year, month, day, hour).


LightTime 
Computes the geocentric position of a solar system body, as antedated for lighttime.


LimbAngle 
Determines the angle of an object above or below the Earth's limb (horizon).


LoadLibrary 
Loads a library DLL


LocalPlanet 
Computes the local place of a solar system body.


LocalStar 
Computes the local place of a star at date 'JdTt', given its catalog mean place, proper motion, parallax, and radial velocity.


MakeCatEntry 
Create a structure of type 'cat_entry' containing catalog data for a star or "starlike" object.


MakeInSpace 
Makes a structure of type 'InSpace'  specifying the position and velocity of an observer situated
on a nearEarth spacecraft.


MakeObject 
Makes a structure of type 'object'  specifying a celestial object  based on the input parameters.


MakeObserver 
Makes a structure of type 'observer'  specifying the location of the observer.


MakeObserverAtGeocenter 
Makes a structure of type 'observer' specifying an observer at the geocenter.


MakeObserverInSpace 
Makes a structure of type 'observer' specifying the position and velocity of an observer
situated on a nearEarth spacecraft.


MakeObserverOnSurface 
Makes a structure of type 'observer' specifying the location of and weather for an observer
on the surface of the Earth.


MakeOnSurface 
Makes a structure of type 'on_surface'  specifying the location of and weather for an
observer on the surface of the Earth.


MeanObliq 
Compute the mean obliquity of the ecliptic.


MeanStar 
Computes the ICRS position of a star, given its apparent place at date 'JdTt'.
Proper motion, parallax and radial velocity are assumed to be zero.


NormAng 
Normalize angle into the range 0 <= angle < (2 * pi).


Nutation 
Nutates equatorial rectangular coordinates from mean equator and equinox of epoch to true equator and equinox of epoch.


NutationAngles 
Returns the values for nutation in longitude and nutation in obliquity for a given TDB Julian date.


Place 
Computes the apparent direction of a star or solar system body at a specified time
and in a specified coordinate system.


PlanetEphemeris 
Get position and velocity of target with respect to the centre object.


Precession 
Precesses equatorial rectangular coordinates from one epoch to another.


ProperMotion 
Applies proper motion, including foreshortening effects, to a star's position.


RaDec2Vector 
Converts equatorial spherical coordinates to a vector (equatorial rectangular coordinates).


RadVel 
Predicts the radial velocity of the observed object as it would be measured by spectroscopic means.


ReadEph 
Produces the Cartesian heliocentric equatorial coordinates of the asteroid for the J2000.0 epoch
coordinate system from a set of Chebyshev polynomials read from a file.


Refract 
Computes atmospheric refraction in zenith distance.


SHGetSpecialFolderPath 
Get path to a system folder


SiderealTime 
Computes the Greenwich sidereal time, either mean or apparent, at Julian date 'JdHigh' + 'JdLow'.


SolarSystem 
Interface between the JPL directaccess solar system ephemerides and NOVASC.


Spin 
Transforms a vector from one coordinate system to another with same origin and axes rotated about the zaxis.


StarVectors 
Converts angular quantities for stars to vectors.


State 
Read and interpolate the JPL planetary ephemeris file.


Tdb2Tt 
Computes the Terrestrial Time (TT) or Terrestrial Dynamical Time (TDT) Julian date corresponding
to a Barycentric Dynamical Time (TDB) Julian date.


Ter2Cel 
This function rotates a vector from the terrestrial to the celestial system.


Terra 
Computes the position and velocity vectors of a terrestrial observer with respect to the center of the Earth.


TopoPlanet 
Computes the topocentric place of a solar system body.


TopoStar 
Computes the topocentric place of a star at date 'JdTt', given its catalog mean place, proper motion, parallax, and radial velocity.


TransformCat 
To transform a star's catalog quantities for a change of epoch and/or equator and equinox.


TransformHip 
Convert Hipparcos catalog data at epoch J1991.25 to epoch J2000.0, for use within NOVAS.


Vector2RaDec 
Converts a vector in equatorial rectangular coordinates to equatorial spherical coordinates.


VirtualPlanet 
Compute the virtual place of a planet or other solar system body.


VirtualStar 
Computes the virtual place of a star at date 'JdTt', given its catalog mean place, proper motion, parallax, and radial velocity.


Wobble 
Corrects a vector in the ITRF (rotating Earthfixed system) for polar motion, and also corrects
the longitude origin (by a tiny amount) to the Terrestrial Intermediate Origin (TIO).
