ASCOM Library
SofaNum
Computes the nutation, precession, and frame bias rotation matrix for a given date using the IAU 2006
precession and IAU 2000A nutation models.
Definition
Namespace: ASCOM.Tools
Assembly: ASCOM.AstrometryTools (in ASCOM.AstrometryTools.dll) Version: 3.0.0-rc.1+86c25ce733aebb4d8b1b8a62e84770ea5e972bea
Assembly: ASCOM.AstrometryTools (in ASCOM.AstrometryTools.dll) Version: 3.0.0-rc.1+86c25ce733aebb4d8b1b8a62e84770ea5e972bea
C#
public static void Num06a(
double date1,
double date2,
double[] rmatn
)VB
Public Shared Sub Num06a (
date1 As Double,
date2 As Double,
rmatn As Double()
)Parameters
- date1 Double
- The first part of the Julian Date representing the Terrestrial Time (TT) of the desired epoch. This value is typically the integer part of the Julian Date.
- date2 Double
- The second part of the Julian Date representing the Terrestrial Time (TT) of the desired epoch. This value is typically the fractional part of the Julian Date.
- rmatn Double
- When the method returns, contains a 3×3 rotation matrix (as a 9-element array in row-major order) that transforms vectors from the mean equator and equinox of J2000.0 to the true equator and equinox of date. The array must have a length of at least 9.
Remarks
This method is a P/Invoke wrapper for the SOFA library function 'iauNum06a'. The
input date should be supplied as a two-part Julian Date to preserve precision. The resulting rotation matrix
can be used to transform celestial coordinates between reference frames. This method does not perform
validation on the input array length.
Exceptions
| ArgumentNullException | Thrown if any array parameter is null. |
| ArgumentException | Thrown if any array parameter has incorrect length. |