One of the first steps that should be taken when examining your data is to check to
see what you actually have. XMM-Newton observations can be broken into several exposures
which are each assigned separate observation numbers. These separate
exposures can be radically different in length and can also have the
different instruments in different modes. For example, in one case
the full observation was 60 ks with EPIC and RGS active but there was
one delivered exposure which was ks and had only RGS active.
(This can happen because the RGS can operate farther into regions of
higher radiation than the EPIC detector. The additional observation
time can be considered an additional exposure with only the RGS
active.) Two files are useful and should be downloaded to the user's
machine for this examination. First, the primary HTML page is
INDEX.HTM which is included in the Pipeline Products. This page
lists basic information for the observation plus the operational modes,
filters, and exposure start and stop times for the individual instruments.
It also has links to various summary pages, including those for the
instruments. (In the case above, the EPIC summary page simply stated that
``EPIC exposures processed by PPS None.'') Specifically, LOOK at the
P*SUMMAR0000.HTM files in the pipeline products (easily available
through the links). Second, to quickly access images from the various
instruments examine the PPSGRA Pipeline Products page
(§ 5.3.3).