SofaGst00a Method

Calculates the Greenwich apparent sidereal time (GAST) at 0h UT1, using the IAU 2000A precession-nutation model.

Definition

Namespace: ASCOM.Tools
Assembly: ASCOM.AstrometryTools (in ASCOM.AstrometryTools.dll) Version: 3.0.0-rc.1+86c25ce733aebb4d8b1b8a62e84770ea5e972bea

C#

public static double Gst00a(
	double uta,
	double utb,
	double tta,
	double ttb
)

VB

Public Shared Function Gst00a ( 
	uta As Double,
	utb As Double,
	tta As Double,
	ttb As Double
) As Double

Parameters

uta Double: The UT1 Julian Date, part A. This value, when added to utb, specifies the UT1 Julian Date as a two-part value for increased precision.
utb Double: The UT1 Julian Date, part B. This value, when added to uta, specifies the UT1 Julian Date as a two-part value for increased precision.
tta Double: The TT (Terrestrial Time) Julian Date, part A. This value, when added to ttb, specifies the TT Julian Date as a two-part value for increased precision.
ttb Double: The TT (Terrestrial Time) Julian Date, part B. This value, when added to tta, specifies the TT Julian Date as a two-part value for increased precision.

Return Value

Double
The Greenwich apparent sidereal time, in radians, in the range 0 to 2π.

Remarks

This method is typically used in astronomical calculations that require precise sidereal time, such as transforming between celestial and terrestrial reference frames. The two-part Julian Date representation allows for high-precision time specification and is recommended for applications requiring full double-precision accuracy.

Version Information

.NET Standard

Supported in: 2.0