In order to
allow observations of relatively bright sources to coexist with the
parallel mode, a change has been made to the details of the AOT-to-OCT
logic, to allow the observer to control the instrument set-up before
and after the actual observation. This is done by adding dummy
observations with the desired observing configurations to the
beginning and to the end of a concatenated chain of observations.
For polarimetric imaging C05 the implementation is such that you may
now specify in your observation template file (``polar.dat'') a new
entry for the key word: SEQ_RESET. In case the target would cause
saturation while arriving in ISOCAM parallel mode you must use:
SEQ_RESET = DARK
This flag will automatically create two dummy observations. First a
dummy off-source position some 5 arcmin North from the desired
pointing position of the target. At this dummy off-source position the
instrument will go into the optical configuration as specified for the
ON source position. Then it will move to the ON source position and
perform the C05 observations. At the end of the polarization
measurements the system will be forced to return to the OFF source
position. The move from OFF to ON and back to OFF will be done by
suppressing the automatic transition to parallel / standby mode, so
that no saturation will happen due to the parallel mode configuration.
If you set SEQ_RESET to DARK the observations will be about 430s more
expensive than without this procedure. For SEQ_RESET=DARK you have to
add 430s to the total target dedicated time (TDT). However, if you
fail to take this precaution when necessary, your observation is
likely to be suppressed during routine screening of schedules.
If you do not need this OFF-ON-OFF procedure you should specify
SEQ_RESET = PARALLEL