﻿ NOVAS31 Methods

NOVAS31 Methods

The NOVAS31 type exposes the following members.

Methods
NameDescription
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 space-fixed system) to the ITRS (a rotating earth-fixed system) by applying rotations for the GCRS-to-dynamical frame tie, precession, nutation, Earth rotation, and polar motion.
CelPole
This function allows for the specification of celestial pole offsets for high-precision 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 light-time, 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.
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 near-earth 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 light-time.
LimbAngle
Determines the angle of an object above or below the Earth's limb (horizon).
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 "star-like" object.
MakeInSpace
Makes a structure of type 'InSpace' - specifying the position and velocity of an observer situated on a near-Earth 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 near-Earth 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.
Converts equatorial spherical coordinates to a vector (equatorial rectangular coordinates).
Predicts the radial velocity of the observed object as it would be measured by spectroscopic means.
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.
SiderealTime
Computes the Greenwich sidereal time, either mean or apparent, at Julian date 'JdHigh' + 'JdLow'.
SolarSystem
Interface between the JPL direct-access solar system ephemerides and NOVAS-C.
Spin
Transforms a vector from one coordinate system to another with same origin and axes rotated about the z-axis.
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.