PN06A Subroutine

  1. astro_module.f90
  2. astro_module
  3. PN06A

public subroutine PN06A(date1, date2, dpsi, deps, epsa, rb, rp, rbp, rn, rbpn)

Precession-nutation, IAU 2006/2000A models: a multi-purpose routine, supporting classical (equinox-based) use directly and CIO-based use indirectly.

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 nutation components (luni-solar + planetary, IAU 2000A) in longitude and obliquity are in radians and with respect to the equinox and ecliptic of date. Free core nutation is omitted; for the utmost accuracy, use the PN06 routine, where the nutation components are caller-specified.

  3. The mean obliquity is consistent with the IAU 2006 precession.

  4. The matrix RB transforms vectors from GCRS to mean J2000.0 by applying frame bias.

  5. The matrix RP transforms vectors from mean J2000.0 to mean of date by applying precession.

  6. The matrix RBP transforms vectors from GCRS to mean of date by applying frame bias then precession. It is the product RP x RB.

  7. The matrix RN transforms vectors from mean of date to true of date by applying the nutation (luni-solar + planetary).

  8. The matrix RBPN transforms vectors from GCRS to true of date (CIP/equinox). It is the product RN x RBP, applying frame bias, precession and nutation in that order.

  9. The X,Y,Z coordinates of the IAU 2006/2000A Celestial Intermediate Pole are elements (3,1-3) of the matrix RBPN.

Reference

  • Capitaine, N. & Wallace, P.T., 2006, Astron.Astrophys. 450, 855

History

  • IAU SOFA revision: 2009 December 15

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)
real(kind=wp), intent(out) :: dpsi

nutation (Note 2)
real(kind=wp), intent(out) :: deps

nutation (Note 2)
real(kind=wp), intent(out) :: epsa

mean obliquity (Note 3)
real(kind=wp), intent(out), dimension(3,3):: rb

frame bias matrix (Note 4)
real(kind=wp), intent(out), dimension(3,3):: rp

precession matrix (Note 5)
real(kind=wp), intent(out), dimension(3,3):: rbp

bias-precession matrix (Note 6)
real(kind=wp), intent(out), dimension(3,3):: rn

nutation matrix (Note 7)
real(kind=wp), intent(out), dimension(3,3):: rbpn

GCRS-to-true matrix (Notes 8,9)

Calls

proc~~pn06a~~CallsGraph proc~pn06a PN06A proc~nut06a NUT06A proc~pn06a->proc~nut06a proc~pn06 PN06 proc~pn06a->proc~pn06 proc~nut00a NUT00A proc~nut06a->proc~nut00a proc~pfw06 PFW06 proc~pn06->proc~pfw06 proc~rxr RXR proc~pn06->proc~rxr proc~tr TR proc~pn06->proc~tr proc~fw2m FW2M proc~pn06->proc~fw2m proc~faom03 FAOM03 proc~nut00a->proc~faom03 proc~faju03 FAJU03 proc~nut00a->proc~faju03 proc~fasa03 FASA03 proc~nut00a->proc~fasa03 proc~fae03 FAE03 proc~nut00a->proc~fae03 proc~fame03 FAME03 proc~nut00a->proc~fame03 proc~fal03 FAL03 proc~nut00a->proc~fal03 proc~fapa03 FAPA03 proc~nut00a->proc~fapa03 proc~faf03 FAF03 proc~nut00a->proc~faf03 proc~fave03 FAVE03 proc~nut00a->proc~fave03 proc~fama03 FAMA03 proc~nut00a->proc~fama03 proc~faur03 FAUR03 proc~nut00a->proc~faur03 proc~obl06 OBL06 proc~pfw06->proc~obl06 proc~rx RX proc~fw2m->proc~rx proc~ir IR proc~fw2m->proc~ir proc~rz RZ proc~fw2m->proc~rz

Contents

Source Code

PN06A

Source Code

    subroutine PN06A ( date1, date2, &
                       dpsi, deps, epsa, rb, rp, rbp, rn, rbpn )

    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),intent(out) :: dpsi !! nutation (Note 2)
    real(wp),intent(out) :: deps !! nutation (Note 2)
    real(wp),intent(out) :: epsa !! mean obliquity (Note 3)
    real(wp),dimension(3,3),intent(out) :: rb !! frame bias matrix (Note 4)
    real(wp),dimension(3,3),intent(out) :: rp !! precession matrix (Note 5)
    real(wp),dimension(3,3),intent(out) :: rbp !! bias-precession matrix (Note 6)
    real(wp),dimension(3,3),intent(out) :: rn !! nutation matrix (Note 7)
    real(wp),dimension(3,3),intent(out) :: rbpn !! GCRS-to-true matrix (Notes 8,9)

    !  Nutation.
    call NUT06A ( date1, date2, dpsi, deps )

    !  Remaining results.
    call PN06 ( date1, date2, dpsi, deps, &
                epsa, rb, rp, rbp, rn, rbpn )

    end subroutine PN06A