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/node128.html | 187 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 187 insertions(+) create mode 100644 src/slalib/sun67.htx/node128.html (limited to 'src/slalib/sun67.htx/node128.html') diff --git a/src/slalib/sun67.htx/node128.html b/src/slalib/sun67.htx/node128.html new file mode 100644 index 0000000..b705fa9 --- /dev/null +++ b/src/slalib/sun67.htx/node128.html @@ -0,0 +1,187 @@ + + + + +SLA_MAPQK - Quick Mean to Apparent + + + + + + + + + + + + +
+ +next + +up + +previous +
+ Next: SLA_MAPQKZ - Quick Mean-Appt, no PM etc. +
+Up: SUBPROGRAM SPECIFICATIONS +
+ Previous: SLA_MAPPA - Mean to Apparent Parameters +

+

+

SLA_MAPQK - Quick Mean to Apparent +   +

+
+
ACTION: +
Quick mean to apparent place: transform a star $[\,\alpha,\delta\,]$ from +mean place to geocentric apparent place, given the + star-independent parameters. The reference frames and + timescales used are post IAU 1976. +

CALL: +
CALL sla_MAPQK (RM, DM, PR, PD, PX, RV, AMPRMS, RA, DA) +

+

+
GIVEN: +
+
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
RM,DMDmean $[\,\alpha,\delta\,]$ (radians)
PR,PDDproper motions: $[\,\alpha,\delta\,]$ changes per Julian year
PXDparallax (arcsec)
RVDradial velocity (km s-1, +ve if receding)
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
+

+
RETURNED: +
+
+ + + + + +
RA,DAD apparent $[\,\alpha,\delta\,]$ (radians)
+

+
NOTES: +
+
1. +
Use of this routine is appropriate when efficiency is important +and where many star positions, all referred to the same equator +and equinox, are to be transformed for one epoch. The + star-independent parameters can be obtained by calling the + sla_MAPPA routine. +
2. +
If the parallax and proper motions are zero the sla_MAPQKZ + routine can be used instead. +
3. +
The vectors AMPRMS(2-4) and AMPRMS(5-7) are referred to + the mean equinox and equator of epoch EQ. +
4. +
Strictly speaking, the routine is not valid for solar-system + sources, though the error will usually be extremely small. + However, to prevent gross errors in the case where the + position of the Sun is specified, the gravitational + deflection term is restrained within about $920\hspace{-0.05em}^{'\hspace{-0.1em}'}$ of the + centre of the Sun's disc. The term has a maximum value of + about + $1\hspace{-0.05em}^{'\hspace{-0.1em}'}\hspace{-0.4em}.85$ at this radius, and decreases to zero as + the centre of the disc is approached. +
+

+
REFERENCES: +
+
1. +
1984 Astronomical Almanac, pp B39-B41. +
2. +
Lederle & Schwan, 1984. Astr.Astrophys. 134, 1-6. +
+
+ +next + +up + +previous +
+ Next: SLA_MAPQKZ - Quick Mean-Appt, no PM etc. +
+Up: SUBPROGRAM SPECIFICATIONS +
+ Previous: SLA_MAPPA - Mean to Apparent Parameters +

+

+

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