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in the dataset. The result of this task is a table, called BlockTable, containing info about the structure of the
observation. Any observation is a composition of observing block (e.g. calibration block and science data
block). The BlockTable contains info, for instance, about how many calibration blocks were executed during
the observation, how many chop-nod cycles or scan legs are contained in the data, etc. Basically, the
BlockTable summarizes, per observation block, several info already contained, per readout, in the Status
Table. This info can help us in checking if the data contains the observation as we have designed it, in
selecting just part of the observation for a preliminary data reduction, in slicing the data as we desire, etc.
The figure above shows a BlockTable example for a chopped observation, in particular a point-source
AOT in the jide DataSetInspector (a similar layout can be obtained in the hipe Editor). The main ingredient
of the BlockTable is the OBCP/DMC number (first column in the example above). This number identifies
what PACS photometer is doing for a given time, that is between the time indexes StartIdx and EndIdx of
our observation. A verbal translation of the OBCP/DMC number is given in the Id and Description columns.
For instance, we can easily see in which part the observation the calibration block was executed
(id="PHOT_CHOP_CS"), or when the PACS photometer is preparing itself fo the next command (Id="OBCP
and DMC preparation" or Id="Undefined") and when the real scientific data are taken and the first chopper
sequence is executed (Id="PHOT_CHOP_TRG_1"). Satellite pointing information/mode (staring,
nod-position A or B, raster point M-N, scan leg number, tracking, hold position, etc.) can also be included
in the BlockTable if findBlock is executed after the execution of the AddInstantPointing task which adds the
pointing information to the frames class. Typical AOT observations might contain several OBCPs and some
of the OBCPs might be executed many times within one AOT observation (as in the example above). A
block contained in a given OBCP/DMC sequence might correspond to different labels. In some cases a
change in label does not necessarily mean a change in chopper position, e.g. see below, block 2 in OBCP
04 "chopper photometry sequence on target" can have labels 1,3, and 5. Here, labels 3 and 5 correspond
very likely to the same chopper position. We list here the OBCP/DMC sequences and the blocks associated
to them (taken from PACS-ME-LI-005, Issue 1.1, 08-Mar-2005) :
OBCP 01: Bolometer transition to IDLE state ---> no DMC sequence, no blocks
OBCP 02: Bolometer operation for unregulated state ---> no DMC sequence, no blocks
OBCP 03: Fixed-Fixed Chopped Photometry ---> DMC sequence 14 blocks:
OBCP and DMC preparation (label undefined, 0)
first chopper sequence on target (labels 3,5)
second chopper sequence on target (labels 7,9)
third chopper sequence on target (labels 11,13)
DMC and OBCP Reset (label 0, undefined)
OBCP 04: Chopped Photometry ---> DMC sequence 1 blocks:
OBCP and DMC preparation (label undefined, 0)
chopper sequence on target (labels 1,3,5)
chopper sequence on CSs (labels 65,129)
DMC and OBCP Reset (label 0, undefined)
/Users/mromanie/tmp/Pxml/dp_workshop.xml
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