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.

Namespace: ASCOM.Astrometry.NOVAS
Assembly: ASCOM.Astrometry (in ASCOM.Astrometry.dll) Version: (


public double[] ReadEph(
	int Mp,
	string Name,
	double Jd,
	ref int Err
Visual Basic
Public Function ReadEph ( _
	Mp As Integer, _
	Name As String, _
	Jd As Double, _
	ByRef Err As Integer _
) As Double()
Visual C++
virtual array<double>^ ReadEph(
	int Mp, 
	String^ Name, 
	double Jd, 
	int% Err
) sealed


Type: System..::..Int32
The number of the asteroid for which the position in desired.
Type: System..::..String
The name of the asteroid.
Type: System..::..Double
The Julian date on which to find the position and velocity.
Type: System..::..Int32%
 = 0 ( No error )
 = 1 ( Memory allocation error )
 = 2 ( Mismatch between asteroid name and number )
 = 3 ( Julian date out of bounds )
 = 4 ( Cannot find Chebyshev polynomial file )

Return Value

6-element array of double containing position and velocity vector values.


The file name of the asteroid is taken from the name given. It is assumed that the name is all in lower case characters.

This routine will search in the application's current directory for a file of Chebyshev polynomial coefficients whose name is based on the provided Name parameter: Name.chby

Further information on using NOVAS with minor planet data is given here:

See Also