EE06A Function

  1. astro_module.f90
  2. astro_module
  3. EE06A

public function EE06A(date1, date2) result(res)

Equation of the equinoxes, compatible with IAU 2000 resolutions and IAU 2006/2000A precession-nutation.

Status: support routine.

Notes

  1. The TT date DATE1+DATE2 is a Julian Date, apportioned in any convenient way between the two arguments. For example, JD(TT)=2450123.7 could be expressed in any of these ways, among others:

        DATE1          DATE2

 2450123.7D0        0D0        (JD method)
  2451545D0      -1421.3D0     (J2000 method)
 2400000.5D0     50123.2D0     (MJD method)
 2450123.5D0       0.2D0       (date & time method)

    The JD method is the most natural and convenient to use in cases where the loss of several decimal digits of resolution is acceptable. The J2000 method is best matched to the way the argument is handled internally and will deliver the optimum resolution. The MJD method and the date & time methods are both good compromises between resolution and convenience.

  2. The result, which is in radians, operates in the following sense:

    Greenwich apparent ST = GMST + equation of the equinoxes

Reference

  • McCarthy, D. D., Petit, G. (eds.), 2004, IERS Conventions (2003), IERS Technical Note No. 32, BKG

History

  • IAU SOFA revision: 2006 October 31

Arguments

TypeIntentOptionalAttributesName
real(kind=wp), intent(in) :: date1

TT as a 2-part Julian Date (Note 1)
real(kind=wp), intent(in) :: date2

TT as a 2-part Julian Date (Note 1)

Return Value real(kind=wp)

equation of the equinoxes (Note 2)


Calls

proc~~ee06a~~CallsGraph proc~ee06a EE06A proc~anpm ANPM proc~ee06a->proc~anpm proc~gmst06 GMST06 proc~ee06a->proc~gmst06 proc~gst06a GST06A proc~ee06a->proc~gst06a proc~anp ANP proc~gmst06->proc~anp proc~era00 ERA00 proc~gmst06->proc~era00 proc~pnm06a PNM06A proc~gst06a->proc~pnm06a proc~gst06 GST06 proc~gst06a->proc~gst06 proc~era00->proc~anp proc~pfw06 PFW06 proc~pnm06a->proc~pfw06 proc~nut06a NUT06A proc~pnm06a->proc~nut06a proc~fw2m FW2M proc~pnm06a->proc~fw2m proc~gst06->proc~anp proc~gst06->proc~era00 proc~eors EORS proc~gst06->proc~eors proc~s06 S06 proc~gst06->proc~s06 proc~bpn2xy BPN2XY proc~gst06->proc~bpn2xy proc~obl06 OBL06 proc~pfw06->proc~obl06 proc~faom03 FAOM03 proc~s06->proc~faom03 proc~falp03 FALP03 proc~s06->proc~falp03 proc~fae03 FAE03 proc~s06->proc~fae03 proc~fal03 FAL03 proc~s06->proc~fal03 proc~faf03 FAF03 proc~s06->proc~faf03 proc~fad03 FAD03 proc~s06->proc~fad03 proc~fave03 FAVE03 proc~s06->proc~fave03 proc~fapa03 FAPA03 proc~s06->proc~fapa03 proc~nut00a NUT00A proc~nut06a->proc~nut00a proc~rx RX proc~fw2m->proc~rx proc~ir IR proc~fw2m->proc~ir proc~rz RZ proc~fw2m->proc~rz proc~nut00a->proc~faom03 proc~nut00a->proc~fae03 proc~nut00a->proc~fal03 proc~nut00a->proc~faf03 proc~nut00a->proc~fave03 proc~nut00a->proc~fapa03 proc~fame03 FAME03 proc~nut00a->proc~fame03 proc~fasa03 FASA03 proc~nut00a->proc~fasa03 proc~faju03 FAJU03 proc~nut00a->proc~faju03 proc~fama03 FAMA03 proc~nut00a->proc~fama03 proc~faur03 FAUR03 proc~nut00a->proc~faur03

Contents

Source Code

EE06A

Source Code

    function EE06A ( date1, date2 ) result(res)

    implicit none

    real(wp),intent(in) :: date1 !! TT as a 2-part Julian Date (Note 1)
    real(wp),intent(in) :: date2 !! TT as a 2-part Julian Date (Note 1)
    real(wp) :: res !! equation of the equinoxes (Note 2)

    !  Equation of the equinoxes.
    res = ANPM ( GST06A ( 0.0_wp, 0.0_wp, date1, date2 ) - &
                 GMST06 ( 0.0_wp, 0.0_wp, date1, date2 ) )

    end function EE06A