earth2sun -- corrects times in the column TIME at the barycenter of the solar system.
earth2sun input column output ra dec
This task corrects the arrival time of photons, assumed as tagged at earth, for the time delay EARTH-SUN. No other corrections are applied, in particular it is not included the corrections for travel time from the satellite-earth or any spacecraft clock delay. This program uses the JPL DE200 ephemeris given as FITS binary table (Standish,M.,1982 Astr. Ap.,114,297). The file validity is till 31 December 2050. The task takes as input only FITS file with binary table extension. The format of the FITS input file can contain many extensions. The task corrects the times only in one selected extension. The selected extension can be specified at the input level (see parameter input file). If the FITS file is an EVENT list the times in the EVENT and GTI extensions are corrected. A file is assumed an EVENT list if the EXTNAME and/or HDUCLAS1 keywords contain the string EVENT (or EVENTS). The column name containing the time values can be specified at input level (see parameter Column name). The default column name is TIME. The time values in the TIME column are expected to be either MJD (or TJD or JD) values (1) or residuals from a MJD reference time (2) given as header keyword. In the first case (the time column contains values written as a MJD or JD or TJD), the header keyword 'TIMESYS' is required, containing with one of the following values: MJD or JD or TJD. In the second case, the keyword 'MJDREF' (or 'MJDREFI', integer part, and 'MJDREFF' fractional part) should contain an MJD value. If MJDREF is not found and TIMESYS is not either MJD or JD or TJD the program gives a fatal error.
A GTI extension is expected in the file if the FITS file is an EVENT list, and it is identified if the either EXTNAME or HDUCLAS1 keyword contain the string GTI (or ALLGTI or STDGTI). The GTI extension format must have at least two columns named START and STOP and no other column named are searched and/or recognized. The task adds and/or replaces a number of header keywords. TIMREF is set to 'SOLARSYSTEM'. TSTART and TSTOP are set either to the first and last value in the TIME column or if an EVENT list to the first start GTI and last stop GTI.
Report problems to angelini@lheavx.gsfc.nasa.gov and xanprob@athena.gsfc.nasa.gov. Provide a detailed description of the problem (with a log file if possible).