Hi,
First of all why would you want Sidereal Time to that level of precision?
I know this is the time-nuts so 'because I can' is a perfectly
acceptable answer.
These days Sidereal Time is only used to display to humans in a
recognizable format an old and outdated approximation to the current
ITRF <-> ICRF transformations that the professionals would use to find
or track a celestial object.
See IERS (http://www.iers.org/IERS/EN/DataProducts/data.html) and SOFA
(http://www.iausofa.org/index.html) for the details and sample code in
FORTRAN and 'C' for these transformations.
I suspect if you want microsecond accuracy you will have to use the SOFA
routines, and have access to the IERS EOP Data.
Cheers
Ken
On 16/06/12 07:20, Chris Albertson wrote:
On Fri, Jun 15, 2012 at 9:49 PM, Mark Sims<hol...@hotmail.com> wrote:
Lady Heather can do sidereal time. Specify either the LMST, LAST, GMST
or GAST time zone (for Local/Greenwich Mean/Apparent Sidereal Time).
I think the question was how to get Sidereal time to the microsecond level.
A computer display screen only gets refreshed roughly 60 to 100 times per
second so a screen can be tens of milliseconds off.
How is this done professionally. Basically they don't. What you do is
record a UTC time code on a track parallel to the data. Or now that
everything is digital, the time code is sampled and multiplexed with the
data. Later the display software can convert the time to whatever format
is desired.
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
