CL_mod_precessionAngles

Description

• This function is deprecated.

• Computes the precession angles according to Lieske precession theory.

  if P0 is the pole of J2000 equator, and P is the pole at time t; if G0 is the equinox of J2000 and G is the equinox at time t:

  zetaa: angle between the meridians (pole P0) P0-P and P0-G0

  thetaa: angle between the equateur J2000 and the equateur t

  za: angle between the meridians (pole P) P-P0 and P-G

Parameters

jj_tai :

(integer) Modified (1950.0) Julian day (1xN)

ss_tai :

seconds (TAI time scale) (1xN)

flag :

(optional) "n" -> K; "p" -> K and Kp; "s" -> K, Kp, Kpp (default depends on number of outputs)

K :

precession angles K = [zetaa;tetaa;za] [rad] (3xN)

KP :

(optional) first time derivative of K [rad/s] (3xN)

KPP :

(optional) second time derivative of K [rad/s^2] (3xN)

Authors

• CNES - DCT/SB

Bibliography

• 1) IERS Conventions (1996), Dennis D. McCarthy

• 2) Explanatory Supplement to the Astronomical Almanac, Seidelman (1992)

See also

• CL_mod_nutationAngles

Examples

jj_tai = [19500:1:20500]; ss_tai = 43200*ones(jj_tai); [K,KP,KPP]=CL_mod_precessionAngles(jj_tai,ss_tai,"s"); plot(jj_tai'+ss_tai'/86400,K');