Chapter 5 (Updated): Transformation between the International Terrestrial Reference System and Geocentric Celestial Reference System
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- 21 December 2013:
- Report the yearly update fcnnut130701 to the Free Core Nutation model
- 10 August 2012:
Changes with respect to previous version of the chapter:
- Report the yearly update fcnnut120701 to the Free Core Nutation model and correct a typo in the value of the FCN period.
- 14 October 2011:
- The header of the subroutine PMSDNUT2.F has been corrected to point to the correct section of Chapter 5 and to provide a new test case.
- 13 July 2011:
Main changes with respect to previous version of the chapter:
- Correct Tables 5.3a and 5.3b: Column headers misplaced in the "paper" version; One typo in the electronic version.
- Report an error in the version of Table 5.3b that was published with the Conventions (2003).
- Correct in Table 5.2f the formula for the polynomial part of Y_IAU 2006 - Y_IAU 2000A.
- Clarify the text describing the implementation of the IAU 2000A nutation model by the SOFA (Software of Fundamental Astronomy) service.
- Report the yearly update fcnnut110701 to the Free Core Nutation model.
- Correct several typos or improper wordings.
- Routines that support the transformations described in Chapter 5 (see Section 5.9) are included in the SOFA collection.
Subroutine to compute the diurnal lunisolar effect on
polar motion. Based on the subroutine PMsdnut.for.
- Differences between the two subroutines are typically smaller than 0.1 μas.
- UTLIBR.F - Subroutine to compute the subdiurnal librations in UT1. 
- FUNDARG.F - Subroutine to compute the lunisolar fundamental arguments. 
- FCNNUT.F - Computes corrections to the coordinates of the CIP to account for Free Core Nutation. Contains data table to be updated each year.  (Updated 10 August 2012)
- Table 5.2a - IAU 2006/2000A expression of the X coordinate of the CIP in the GCRS. 
- Table 5.2b - IAU 2006/2000A expression of the Y coordinate of the CIP in the GCRS. 
- Table 5.2d - IAU 2006/2000A expression of the quantity s(t) + XY/2.
- Table 5.2e - IAU 2006/2000A expression for Greenwich Sidereal Time GST. 
- Table 5.2f - Expression for the difference between the IAU 2006 (or IAU 2000A_R06) and IAU 2000 expression for various quantities (X, Y, Dpsi, Deps, s+XY/2). 
- Table 5.3a - Nutation in longitude (IAU 2000_R06 expression) derived from the IAU 2000A lunisolar and planetary components with slight IAU 2006 adjustments. 
- Table 5.3b - Nutation in obliquity (IAU 2000_R06 expression) derived from the IAU 2000A lunisolar and planetary components with slight IAU 2006 adjustments. 
 Provided by A. Brzezinski.
 From the model by Simon et al. (1994).
 Provided by S. Lambert
 Provided by N. Capitaine