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Star Class

Note: This API is now obsolete.

NOVAS-COM: Star Class
Inheritance Hierarchy

Namespace: ASCOM.Astrometry.NOVASCOM
Assembly: ASCOM.Astrometry (in ASCOM.Astrometry.dll) Version: (
[ObsoleteAttribute("This class will be withdrawn in the next major release, please use the SOFA or NOVAS31 classes instead")]
public class Star

The Star type exposes the following members.

Public methodStar
Initialise a new instance of the star class
Public propertyCatalog
Three character catalog code for the star's data
Public propertyDeclination
Mean catalog J2000 declination coordinate (degrees)
Public propertyDeltaT
The value of delta-T (TT - UT1) to use for reductions.
Public propertyEarthEphemeris
Ephemeris object used to provide the position of the Earth.
Public propertyName
The catalog name of the star (50 char max)
Public propertyNumber
The catalog number of the star
Public propertyParallax
Catalog mean J2000 parallax (arcsec)
Public propertyProperMotionDec
Catalog mean J2000 proper motion in declination (arcsec/century)
Public propertyProperMotionRA
Catalog mean J2000 proper motion in right ascension (sec/century)
Public propertyRadialVelocity
Catalog mean J2000 radial velocity (km/sec)
Public propertyRightAscension
Catalog mean J2000 right ascension coordinate (hours)
Public methodGetApparentPosition
Get an apparent position for a given time
Public methodGetAstrometricPosition
Get an astrometric position for a given time
Public methodGetLocalPosition
Get a local position for a given site and time
Public methodGetTopocentricPosition
Get a topocentric position for a given site and time
Public methodGetVirtualPosition
Get a virtual position at a given time
Public methodSet
Initialize all star properties with one call
Public methodSetHipparcos
Initialise all star properties in one call using Hipparcos data. Transforms to FK5 standard used by NOVAS.
NOVAS-COM objects of class Star contain the specifications for a star's catalog position in either FK5 or Hipparcos units (both must be J2000). Properties are right ascension and declination, proper motions, parallax, radial velocity, catalog type (FK5 or HIP), catalog number, optional ephemeris engine to use for barycenter calculations, and an optional value for delta-T. Unless you specifically set the DeltaT property, calculations performed by this class which require the value of delta-T (TT - UT1) rely on an internal function to estimate delta-T.

The high-level NOVAS astrometric functions are implemented as methods of Star: GetTopocentricPosition(), GetLocalPosition(), GetApparentPosition(), GetVirtualPosition(), and GetAstrometricPosition(). These methods operate on the properties of the Star, and produce a PositionVector object. For example, to get the topocentric coordinates of a star, simply create and initialize a Star, then call Star.GetTopocentricPosition(). The resulting vaPositionVector's right ascension and declination properties are the topocentric equatorial coordinates, at the same time, the (optionally refracted) alt-az coordinates are calculated, and are also contained within the returned PositionVector. Note that Alt/Az is available in PositionVectors returned from calling GetTopocentricPosition().

See Also