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author | Joe Hunkeler <jhunkeler@gmail.com> | 2015-08-11 16:51:37 -0400 |
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committer | Joe Hunkeler <jhunkeler@gmail.com> | 2015-08-11 16:51:37 -0400 |
commit | 40e5a5811c6ffce9b0974e93cdd927cbcf60c157 (patch) | |
tree | 4464880c571602d54f6ae114729bf62a89518057 /math/slalib/doc/gmst.hlp | |
download | iraf-osx-40e5a5811c6ffce9b0974e93cdd927cbcf60c157.tar.gz |
Repatch (from linux) of OSX IRAF
Diffstat (limited to 'math/slalib/doc/gmst.hlp')
-rw-r--r-- | math/slalib/doc/gmst.hlp | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/math/slalib/doc/gmst.hlp b/math/slalib/doc/gmst.hlp new file mode 100644 index 00000000..7e58aec9 --- /dev/null +++ b/math/slalib/doc/gmst.hlp @@ -0,0 +1,41 @@ +.help gmst Jun99 "Slalib Package" +.nf + + DOUBLE PRECISION FUNCTION slGMST (UT1) + + - - - - - + G M S T + - - - - - + + Conversion from universal time to sidereal time (double precision) + + Given: + UT1 dp universal time (strictly UT1) expressed as + modified Julian Date (JD-2400000.5) + + The result is the Greenwich mean sidereal time (double + precision, radians). + + The IAU 1982 expression (see page S15 of 1984 Astronomical + Almanac) is used, but rearranged to reduce rounding errors. + This expression is always described as giving the GMST at + 0 hours UT. In fact, it gives the difference between the + GMST and the UT, which happens to equal the GMST (modulo + 24 hours) at 0 hours UT each day. In this routine, the + entire UT is used directly as the argument for the + standard formula, and the fractional part of the UT is + added separately; note that the factor 1.0027379... does + not appear. + + See also the routine slGMSA, which delivers better numerical + precision by accepting the UT date and time as separate arguments. + + Called: slDA2P + + P.T.Wallace Starlink 14 September 1995 + + Copyright (C) 1995 Rutherford Appleton Laboratory + Copyright (C) 1995 Association of Universities for Research in Astronomy Inc. + +.fi +.endhelp |