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/node116.html | 116 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 116 insertions(+) create mode 100644 src/slalib/sun67.htx/node116.html (limited to 'src/slalib/sun67.htx/node116.html') diff --git a/src/slalib/sun67.htx/node116.html b/src/slalib/sun67.htx/node116.html new file mode 100644 index 0000000..5055ecb --- /dev/null +++ b/src/slalib/sun67.htx/node116.html @@ -0,0 +1,116 @@ + + + + +SLA_GMSTA - UT to GMST (extra precision) + + + + + + + + + + + + +
+ +next + +up + +previous +
+ Next: SLA_GRESID - Gaussian Residual +
+Up: SUBPROGRAM SPECIFICATIONS +
+ Previous: SLA_GMST - UT to GMST +

+

+

SLA_GMSTA - UT to GMST (extra precision) +   +

+
+
ACTION: +
Conversion from universal time UT1 to Greenwich Mean +sidereal time, with rounding errors minimized. +

CALL: +
D = sla_GMSTA (DATE, UT1) +

+

+
GIVEN: +
+
+ + + + + + + + + +
DATEDUT1 date as Modified Julian Date (integer part +of JD-2400000.5)
UT1DUT1 time (fraction of a day)
+

+
RETURNED: +
+
+ + + + + +
sla_GMSTDGreenwich mean sidereal time (radians)
+

+
NOTES: +
+
1. +
The algorithm is derived from the IAU 1982 expression +(see page S15 of the 1984 Astronomical Almanac). +
2. +
There is no restriction on how the UT is apportioned between the + DATE and UT1 arguments. Either of the two arguments could, for + example, be zero and the entire date+time supplied in the other. + However, the routine is designed to deliver maximum accuracy when + the DATE argument is a whole number and the UT1 argument + lies in the range $[\,0,\,1\,]$, or vice versa. +
3. +
See also the routine sla_GMST, which accepts the UT1 as a single + argument. Compared with sla_GMST, the extra numerical precision + delivered by the present routine is unlikely to be important in + an absolute sense, but may be useful when critically comparing + algorithms and in applications where two sidereal times close + together are differenced. +
+
+ +next + +up + +previous +
+ Next: SLA_GRESID - Gaussian Residual +
+Up: SUBPROGRAM SPECIFICATIONS +
+ Previous: SLA_GMST - UT to GMST +

+

+

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