XMM-Newton Science Analysis System


tools (tools-1.68.1) [xmmsas_20230412_1735-21.0.0]

satvelsrc: SATellite VELocity in SouRCe direction

• SYNOPSIS
  satvelsrc withsrccoord=yes|no srcra=<ra> srcdec=<dec> withorthosrc=yes|no
                tdelt=<tdelt> withmjdoffset=yes|no mjdoffset=<intmjd>
                withexplicittimes=yes|no tfrom=<t0> tto=<t1>
  
• DESCRIPTION
  satvelsrc computes as a function of time the component of the spacecraft velocity vector in the direction of given celestial source. The source coordinates are obtained from the summary file in the ODF being pointed at by the environment variable
  SAS_ODF
  
  or named via the generic command line parameters -o or –odfdir (see taskmain for details). The specification of an ODF directory on the command line has a higher precedence than any environment setting. The source coordinates obtained from the ODF can be overridden with the command line paramters withsrccoord=yes srcra=<ra> srcdec=<dec> and withorthosrc=yes defines a fictitious source in the direction perpendicular to the orbital plane. In this case the velocity component should be constantly zero at all times which is an important check for the integrity of the orbit file in the ODF.

  The velocity is printed as a function of time (units: days - integer part of MJD) in units of km/s in steps of tdelt to stdout. The time range is automatically chosen to be the duration of the observation but can also be explicitly given via the command line parameters withexplicittimes=yes tfrom=<t0> tto=<t1>. The parameters withmjdoffset=yes mjdoffset=<intmjd> define an integer MJD number by which all times will be offset with - if omitted the values shall be computed from the start of the observation.

• REFERENCE