XMM-Newton Science Analysis System


esky2det (esky2det-1.19.2) [xmmsas_20230412_1735-21.0.0]

Task requirements.

The task clearly needs to know the direction in space of the focal axis of the relevant instrument at the time of the observation of interest. There are three necessary pieces of information: the name of the instrument, the date-time of the observation and the spacecraft pointing direction (attitude) at this time. The task processes these as follows: the instrument identification and the observation date-time are used together to calculate (from values stored in the CCF) the instrument boresight correction at the time of the observation; this correction is then applied to the spacecraft pointing.

There are two ways to pass the `cal' information to esky2det, governed by the parameter calinfostyle:

1. calinfostyle = `set': the information is sought from INSTRUME, DATE-OBS etc keywords in the header of the source list specified by calinfoset. These should be found in the primary headers of all XMM product data sets. It is recommended to use the source list itself as the calinfoset, provided it is an XMM product, and from the same instrument.

2. calinfostyle = `user': the information must be provided by the user via the parameters instrument, datetime, scattra, scattdec and scattapos.

In order to be able to apply the correct boresight correction, as well as to have access to the instrument specifications, the task requires access to the CCF components relevant to the dates of observation and analysis. This is achieved in the usual way by constructing a cif file with cifbuild and pointing to it with the environment variable SAS_CCF.