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XMM-Newton Science Analysis System


dscheck (dscheck-0.4) [xmmsas_20050815_1803-6.5.0]

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Description

This task performs a range of low-level checks on the contents of datasets (FITS files). Examples are:

• Ensuring a FITS file contains an extension of a given name
• Ensuring a FITS HDU (primary or extension) contains a keyword of a given name
• Ensuring a FITS binary table contains a column of a given name
• Checking that a FITS keyword falls in a specified range
• Checking that the values in a column of a FITS table fall within a specified range

The checking process it table-driven, ie. the checks to be performed are defined in an ASCII file. The format of this file is best demonstrated by example:

	# This is a comment
1	EXISTS PRIMARY.CONTENT	Check existence of a keyword in primary header
		(Blank lines are ignored)
2	EXISTS SRCLIST	Check existence of extension named SRCLIST
3	EXISTS SRCLIST.TESTKEY	Check existence of keyword in extension named SRCLIST
4	EXISTS SRCLIST.SRC_NUM[]	Check existence of column in a table named SRCLIST
5	RANGE PRIMARY.RA_PNT 0 360	Check range of keyword in primary header
6	RANGE PRIMARY.DEC_PNT -90 90
7	RANGE SRCLIST.TESTKEY -500 100	Check range of keyword in extension named SRCLIST
8	RANGE SRCLIST.SCTS[] 0 1000	Check range of values in column SCTS of table named SRCLIST

There is some implicit checking performed behind the scenes, eg. checking the range of a keyword implicitly checks for it's existence, and checking the existence of a keyword implicitly checks for the existence of the header it is in. Thus in the table above check 3 implies check 2, and check 7 implies check 3 which implies check 2 (ie. checks 2 and 3 are redundant).

When anomalies are found they are written to STDOUT. All checks will be performed before the task exits. If any checks fail the task will exit with an error, otherwise it will exit normally (this is the mechanism for communicating with the pipeline control system).