Timescales

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/node217.html | 92 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) create mode 100644 src/slalib/sun67.htx/node217.html (limited to 'src/slalib/sun67.htx/node217.html') diff --git a/src/slalib/sun67.htx/node217.html b/src/slalib/sun67.htx/node217.html new file mode 100644 index 0000000..b6fbe6c --- /dev/null +++ b/src/slalib/sun67.htx/node217.html @@ -0,0 +1,92 @@ + + + + +Timescales + + + + + + + + + + + + +

+ +

+
+ Next: Atomic Time: TAI +
+Up: EXPLANATION AND EXAMPLES +
+ Previous: The Hipparcos Catalogue and the ICRS +

+Timescales +

+SLALIB provides for conversion between several timescales, and involves +use of one or two others. The full list is as follows: +

TAI: International Atomic Time +
UTC: Coordinated Universal Time +
UT: Universal Time +
GMST: Greenwich Mean Sidereal Time +
LAST: Local Apparent Sidereal Time +
TT: Terrestrial Time +
TDB: Barycentric Dynamical Time. +

+Three obsolete timescales should be mentioned here to avoid confusion. +

GMT: Greenwich Mean Time - can mean either UTC or UT. +
ET: Ephemeris Time - more or less the same as either TT or TDB. +
TDT: Terrestrial Dynamical Time - former name of TT. +

+ + +

+ +

+
+ Next: Atomic Time: TAI +
+Up: EXPLANATION AND EXAMPLES +
+ Previous: The Hipparcos Catalogue and the ICRS +

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

+ + -- cgit