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.help precl Jun99 "Slalib Package"
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SUBROUTINE slPREL (EP0, EP1, RMATP)
- - - - - -
P R E L
- - - - - -
Form the matrix of precession between two epochs, using the
model of Simon et al (1994), which is suitable for long
periods of time.
(double precision)
Given:
EP0 dp beginning epoch
EP1 dp ending epoch
Returned:
RMATP dp(3,3) precession matrix
Notes:
1) The epochs are TDB Julian epochs.
2) The matrix is in the sense V(EP1) = RMATP * V(EP0)
3) The absolute accuracy of the model is limited by the
uncertainty in the general precession, about 0.3 arcsec per
1000 years. The remainder of the formulation provides a
precision of 1 mas over the interval from 1000AD to 3000AD,
0.1 arcsec from 1000BC to 5000AD and 1 arcsec from
4000BC to 8000AD.
Reference:
Simon, J.L. et al., 1994. Astron.Astrophys., 282, 663-683.
Called: slDEUL
P.T.Wallace Starlink 23 August 1996
Copyright (C) 1996 Rutherford Appleton Laboratory
Copyright (C) 1995 Association of Universities for Research in Astronomy Inc.
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