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/node80.html | 111 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 111 insertions(+) create mode 100644 src/slalib/sun67.htx/node80.html (limited to 'src/slalib/sun67.htx/node80.html') diff --git a/src/slalib/sun67.htx/node80.html b/src/slalib/sun67.htx/node80.html new file mode 100644 index 0000000..e7704f5 --- /dev/null +++ b/src/slalib/sun67.htx/node80.html @@ -0,0 +1,111 @@ + + + + +SLA_DTT - TT minus UTC + + + + + + + + + + + + +
+ +next + +up + +previous +
+ Next: SLA_DV2TP - Direction Cosines to Tangent Plane +
+Up: SUBPROGRAM SPECIFICATIONS +
+ Previous: SLA_DTPV2C - Plate centre from and x,y,z +

+

+

SLA_DTT - TT minus UTC +   +

+
+
ACTION: +
Compute $\Delta$TT, the increment to be applied to +Coordinated Universal Time UTC to give + Terrestrial Time TT. +

CALL: +
D = sla_DTT (DJU) +

+

+
GIVEN: +
+
+ + + + + +
DJUDUTC date as a modified JD (JD-2400000.5)
+

+
RETURNED: +
+
+ + + + + +
sla_DTTDTT-UTC in seconds
+

+
NOTES: +
+
1. +
The UTC is specified to be a date rather than a time to indicate +that care needs to be taken not to specify an instant which lies +within a leap second. Though in most cases UTC can include the + fractional part, correct behaviour on the day of a leap second + can be guaranteed only up to the end of the second + $23^{\rm h}\,59^{\rm m}\,59^{\rm s}$.
2. +
Pre 1972 January 1 a fixed value of 10 + ET-TAI is returned. +
3. +
TT is one interpretation of the defunct timescale + Ephemeris Time, ET. +
4. +
See also the routine sla_DT, which roughly estimates ET-UT for + historical epochs. +
+
+ +next + +up + +previous +
+ Next: SLA_DV2TP - Direction Cosines to Tangent Plane +
+Up: SUBPROGRAM SPECIFICATIONS +
+ Previous: SLA_DTPV2C - Plate centre from and x,y,z +

+

+

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