From d54fe7c1f704a63824c5bfa0ece65245572e9b27 Mon Sep 17 00:00:00 2001 From: Joseph Hunkeler Date: Wed, 4 Mar 2015 21:21:30 -0500 Subject: Initial commit --- src/slalib/sun67.htx/node127.html | 159 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 159 insertions(+) create mode 100644 src/slalib/sun67.htx/node127.html (limited to 'src/slalib/sun67.htx/node127.html') diff --git a/src/slalib/sun67.htx/node127.html b/src/slalib/sun67.htx/node127.html new file mode 100644 index 0000000..6ed5222 --- /dev/null +++ b/src/slalib/sun67.htx/node127.html @@ -0,0 +1,159 @@ + + + + +SLA_MAPPA - Mean to Apparent Parameters + + + + + + + + + + + + +
+ +next + +up + +previous +
+ Next: SLA_MAPQK - Quick Mean to Apparent +
+Up: SUBPROGRAM SPECIFICATIONS +
+ Previous: SLA_MAP - Mean to Apparent +

+

+

SLA_MAPPA - Mean to Apparent Parameters +   +

+
+
ACTION: +
Compute star-independent parameters in preparation for +conversions between mean place and geocentric apparent place. + The parameters produced by this routine are required in the + parallax, light deflection, aberration, and precession/nutation + parts of the mean/apparent transformations. + The reference frames and timescales used are post IAU 1976. +

CALL: +
CALL sla_MAPPA (EQ, DATE, AMPRMS) +

+

+
GIVEN: +
+
+ + + + + + + + + +
EQDepoch of mean equinox to be used (Julian)
DATEDTDB (JD-2400000.5)
+

+
RETURNED: +
+
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
AMPRMSD(21)star-independent mean-to-apparent parameters:
(1)time interval for proper motion (Julian years)
(2-4)barycentric position of the Earth (AU)
(5-7)heliocentric direction of the Earth (unit vector)
(8)(gravitational radius of +Sun)$\times 2 / $(Sun-Earth distance)
(9-11)v: barycentric Earth velocity in units of c
(12)$\sqrt{1-\left\vert\mbox{\bf v}\right\vert^2}$
(13-21)precession/nutation $3\times3$ matrix
+

+
NOTES: +
+
1. +
For DATE, the distinction between the required TDB and TT +is always negligible. Moreover, for all but the most +critical applications UTC is adequate. +
2. +
The accuracy of the routines using the parameters AMPRMS is + limited by the routine sla_EVP, used here to compute the + Earth position and velocity by the methods of Stumpff. + The maximum error in the resulting aberration corrections is + about 0.3 milliarcsecond. +
3. +
The vectors AMPRMS(2-4) and AMPRMS(5-7) are referred to + the mean equinox and equator of epoch EQ. +
4. +
The parameters produced by this routine are used by + sla_MAPQK and sla_MAPQKZ. +
+

+
REFERENCES: +
+
1. +
1984 Astronomical Almanac, pp B39-B41. +
2. +
Lederle & Schwan, 1984. Astr.Astrophys. 134, 1-6. +
+
+ +next + +up + +previous +
+ Next: SLA_MAPQK - Quick Mean to Apparent +
+Up: SUBPROGRAM SPECIFICATIONS +
+ Previous: SLA_MAP - Mean to Apparent +

+

+

+SLALIB --- Positional Astronomy Library
Starlink User Note 67
P. T. Wallace
12 October 1999
E-mail:ptw@star.rl.ac.uk +
+ + -- cgit