PHT40 (Low-Resolution Spectrophotometry with PHT-S and/or PHT-L Detector Arrays)
(July 4, 1995)
PHT40 (Low-Resolution Spectrophotometry with PHT-S and/or PHT-L Detector Arrays)
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Prior to your visit at IPAC, for each target, please prepare the following parameters for
entry into the PGA:
* this AOT does not perform FCS calibration internally (see PHT_manual p80).
==> Common Data for All AOTs (explained on a separate sheet).
==> Parameters for This AOT:
o PEAK-UP: (Y or N) Pick-Up flag for High Precision Pointing (HPP). If the nominal
spacecraft pointing accuracy (~ 12") is not enough, this flag should be
set to Y and the default option of picking up on a nearby bright source
should be selected.
o RASTER: (Y or N) Y = a raster map and N = a single pointing observation. For a raster,
neither PICK-UP nor CHOPPING is allowed. The following parameters are needed
for a raster:
o M = number of pointings along each raster leg (the orientation axis) (<=32).
o N = number of raster legs (<=32).
o STEP = Step sizes in arcsec in each of the two directions.
o REFERENCE FRAME (Y or N) = Reference frame defined with respect to either
the spacecraft Y-axis (Y) or the celestial North (N). In the latter case,
the raster orientation axis may not be aligned with the spacecraft Y-axis,
and the following ORIENTATION ANGLE has to be specified.
o ORIENTATION ANGLE = The angle of the raster orientation axis with respect
to the REFERENCE FRAME (N to E, 0-180 deg).
o CHOPPER: (Y or N) Chopping (Y) or staring mode (N) for a pointed observation. Note: due
to detector drift effect, chopping is not recommended for sources that are
brighter than the background, say, by more than a factor of 2 or 3). The
following parameters are needed for chopping:
o CHOPPER MODE: Rectangular/Triangular/Sawtooth.
o CHOPPER THROW: Select one from the on-screen list (cf. ISOPHOT manual).
o CHOPPER AVOIDANCE ANGLE (Y or N): If yes, specify the starting and ending
position angles (N to E). Note that since the chopping has to be along the
spacecraft Y-axis, a large angle here may tighten constraints on scheduling
this AOT.
o SOURCE TYPE: P (point source) or E (extended source)
o LINE OR CONTINUUM: Select LINE if the parameters for this observation are to be given
below for a spectral line or CONTINUUM if they are for part of a continuum.
o SELECT RANGE: Select SS, SL or BOTH as the wavelength ranges for optimizing the
dynamic settings of the detectors. For example, selection of SS if one does
not care if SL is saturated or not. Note: it is impossible to optimize both
ranges if the spectral flux differs by more than a factor of 100 between the
two ranges.
* S/N: Leave 0.0 if you want to enter the INTEGRATION TIME below or enter the requested
minimum signal-to-noise ratio.
* INTEGRATION TIME: Leave 0.0 if you have requested a minimum S/N ratio or enter the
requested minimum integration time. Notes: (1) For a single pointing observation
with or without chopping, this is the on-source integration time expressed in
a power of 2 seconds (if you input a non-power of 2, the software will round up your
value, e.g., 129 -> 256). (2) For a raster, this is the integration time per raster
point. (3) Because of the detector drift effect, a minimum (on-source) integration
of 32 sec is recommended to achieve a 5% accuracy in the relative flux calibration.
==> Parameters for Each of the Two Spectral Ranges (2.5-5.0um or 6.0-12um):
o MAXIMUM UNSATURATED SOURCE FLUX: In 1.0E-16 W/m^2 (for LINE) or Jy (for CONTINUUM,
Point source) or MJy (CONTINUUM, Extended source)
o MAXIMUM BACKGROUND FLUX DENSITY: In units of MJy/sr
o DETECTION LIMIT: Lower limit of source flux (same units as MAX UNSAT. SOURCE FLUX)