BPN2XY Subroutine

  1. astro_module.f90
  2. astro_module
  3. BPN2XY

public subroutine BPN2XY(rbpn, x, y)

Extract from the bias-precession-nutation matrix the X,Y coordinates of the Celestial Intermediate Pole.

Status: support routine.

Notes

  1. The matrix RBPN transforms vectors from GCRS to true equator (and CIO or equinox) of date, and therefore the Celestial Intermediate Pole unit vector is the bottom row of the matrix.

  2. X,Y are components of the Celestial Intermediate Pole unit vector in the Geocentric Celestial Reference System.

Reference

  • Capitaine, N., Chapront, J., Lambert, S. and Wallace, P., "Expressions for the Celestial Intermediate Pole and Celestial Ephemeris Origin consistent with the IAU 2000A precession-nutation model", Astron.Astrophys. 400, 1145-1154 (2003)

  • n.b. The celestial ephemeris origin (CEO) was renamed "celestial intermediate origin" (CIO) by IAU 2006 Resolution 2.

History

  • IAU SOFA revision: 2010 January 18

Arguments

TypeIntentOptionalAttributesName
real(kind=wp), intent(in), dimension(3,3):: rbpn

celestial-to-true matrix (Note 1)
real(kind=wp), intent(out) :: x

Celestial Intermediate Pole (Note 2)
real(kind=wp), intent(out) :: y

Celestial Intermediate Pole (Note 2)

Called by

proc~~bpn2xy~~CalledByGraph proc~bpn2xy BPN2XY proc~s06a S06A proc~s06a->proc~bpn2xy proc~c2ibpn C2IBPN proc~c2ibpn->proc~bpn2xy proc~c2i06a C2I06A proc~c2i06a->proc~bpn2xy proc~xys00a XYS00A proc~xys00a->proc~bpn2xy proc~apco13 APCO13 proc~apco13->proc~bpn2xy proc~xys06a XYS06A proc~xys06a->proc~bpn2xy proc~gst06 GST06 proc~gst06->proc~bpn2xy proc~s00a S00A proc~s00a->proc~bpn2xy proc~eo06a EO06A proc~eo06a->proc~bpn2xy proc~s00b S00B proc~s00b->proc~bpn2xy proc~apci13 APCI13 proc~apci13->proc~bpn2xy proc~fw2xy FW2XY proc~fw2xy->proc~bpn2xy proc~xys00b XYS00B proc~xys00b->proc~bpn2xy proc~atco13 ATCO13 proc~atco13->proc~apco13 proc~gst06a GST06A proc~gst06a->proc~gst06 proc~atci13 ATCI13 proc~atci13->proc~apci13 proc~atic13 ATIC13 proc~atic13->proc~apci13 proc~c2i00a C2I00A proc~c2i00a->proc~c2ibpn proc~c2i00b C2I00B proc~c2i00b->proc~c2ibpn proc~c2t06a C2T06A proc~c2t06a->proc~c2i06a proc~atoc13 ATOC13 proc~atoc13->proc~apco13 proc~ee06a EE06A proc~ee06a->proc~gst06a proc~c2t00a C2T00A proc~c2t00a->proc~c2i00a proc~c2t00b C2T00B proc~c2t00b->proc~c2i00b

Contents

Source Code

BPN2XY

Source Code

    subroutine BPN2XY ( rbpn, x, y )

    implicit none

    real(wp),dimension(3,3),intent(in) :: rbpn !! celestial-to-true matrix (Note 1)
    real(wp),intent(out) :: x !! Celestial Intermediate Pole (Note 2)
    real(wp),intent(out) :: y !! Celestial Intermediate Pole (Note 2)

    !  Extract the X,Y coordinates.
    x = rbpn(3,1)
    y = rbpn(3,2)

    end subroutine BPN2XY