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SLA_GEOC - Geodetic to Geocentric
ACTION:
Convert geodetic position to geocentric.
CALL:
CALL sla_GEOC (P, H, R, Z)
GIVEN:
P
D
latitude (geodetic, radians)
H
D
height above reference spheroid (geodetic, metres)
RETURNED:
R
D
distance from Earth axis (AU)
Z
D
distance from plane of Earth equator (AU)
NOTES:
1.
Geocentric latitude can be obtained by evaluating
ATAN2(Z,R)
.
2.
IAU 1976 constants are used.
REFERENCE:
Green, R.M., 1985.
Spherical Astronomy
, Cambridge U.P., p98.
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SLALIB --- Positional Astronomy Library
Starlink User Note 67
P. T. Wallace
12 October 1999
E-mail:ptw@star.rl.ac.uk