On Fri 2019-01-18T15:18:08-0600 Didier Juges hath writ: > //----------------------------------------------------------------------- > // Craig Haley 20/09/01 > // 30-06-04 CSH made small changes > // 05-01-05 CSH modified to use mjd rather than converting to jd > // Didier Juges > // 18Jan19 converted to C. > //----------------------------------------------------------------------- > /* original Mathlab code: > * mjd2000 = 51544.5; %Modified Julian Date of Epoch J2000.0 > * int_mjd = floor(mjd); > * frac_mjd = mjd-int_mjd; > * Tu = (int_mjd-mjd2000)/36525.0; > * gmst = 24110.54841+Tu.*(8640184.812866+Tu.*(0.093104-Tu*6.2e-6)); > * %add the mean sidereal time interval from midnight to time > * gmst = mod(gmst+frac_mjd*86400*1.00273790934,86400); > * %convert to hours > * gmst = gmst/3600; > */
This is the expression for use with FK5 that was codified by Aoki et al. in http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1982A%26A...105..359A It is required that this expression be evaluated at 0h UT, which means that the argument in days since epoch must be half integral +/-0.5, +/-1.5 etc. This expression is no longer in use. It was superseded Capitaine et al. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2003A%26A...406.1135C in which formalism it is explicitly disavowed that earth rotation is time. This is also far afield from the kind of time usually in this group. -- Steve Allen <[email protected]> WGS-84 (GPS) UCO/Lick Observatory--ISB 260 Natural Sciences II, Room 165 Lat +36.99855 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 https://www.ucolick.org/~sla/ Hgt +250 m _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
