JD2Dt

Contents: Description, Arguments, Usage, Examples, Sub-Functions, Related Functions, Source Supported Under Version: > 1.15 Current .dvrc Version:  Description Convert UTC Julian date to J2000.0 TT offset (accounts for leap seconds) Arguments and Return Values Parameters: Numeric array specifying the UTC Julian Dates to convert to J2000.0 TT offsets Return Value: The corresponding set of J2000.0 TT offsets (in days) Usage Syntax: JD2Dt(JD) The Julian Date (JD) is a continuous count of days since noon UTC on January 1, 4713 BCE in the proleptic Julian calendar. The J2000.0 TT offset (ΔtJ2000) is a continuous count of days since noon TT on January 1, 2000. This offset is the input to marstimeglobal. Coordinated Universal Time (UTC) is the basis for the time system used in everyday life. In order to keep UTC consistent with the Earth's slightly variable rate of rotation, leap seconds are occasionally inserted into UTC. Terrestrial Time (TT) is a time system with no leap seconds. Returns double-precision J2000.0 TT offsets. The returned values are as accurate as the input, although that accuracy may be further limited by uncertainty in Delta-T. See the function DeltaT for details. For more information, see http://heasarc.gsfc.nasa.gov/docs/xte/abc/time_tutorial.html and http://www.giss.nasa.gov/tools/mars24/help/algorithm.html. When JD2Dt() is entered without any arguments, it prints its description, as shown below. Examples dv> JD2Dt() Convert UTC Julian date to J2000.0 TT offset JD2Dt(JD) returns number of days since noon TT on January 1, 2000 Accounts for leap seconds Works for array inputs Returns double-precision offset, in days The returned values are as accurate as the input, although that accuracy may be further limited by uncertainty in Delta-T. See the function DeltaT for details. See http://www.giss.nasa.gov/tools/mars24/help/algorithm.html S.Marshall 06-29-2008 0 dv> a = JD(2010, 1, 1, 12, 0, 0) 2455198.00000000 dv> JD2Dt(a) 3653.00076601841

DavinciWiki Mini-Nav Bar Contents Functions Function Categories Common Procedures Glossary Download Davinci Change Log News Mailing List Contact Developers davinci-dev [AT] mars.asu.edu All other topics See navigation on the left Major Sub-Functions JD2TT Related Functions clock DeltaT earthtime JD JD2ET JD2TT marstimeglobal MJD2Dt time.dvrc JD2Dt() Recent Library Changes Change Log Created On: 11-18-2009 Modified On: 05-07-2010