Figure1. Comparison of 160micron Illumination Corrections obtained in PHOTOMETRY (left) and SCAN modes (right). Both are displayed from z1=0. to z2=2.
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In PHOTOMETRY mode we obtained a 9 point dither map (1
cycle) at 160micron with 3 second DCEs of one region of
the sky (zodi_28b) chosen to avoid bright point sources.
The offsets between positions are 300 arcseconds. At each position of the dither pattern
there are 16 images (4 of which are stim flashes), so a total of 108
sky images were obtained to construct the 160micron Illumination Correction (IC).
In SCAN mode we have observed 2 degrees (1 leg) in fast mode for three different regions of
the sky (zodi_13a, zodi_28a, and zodi28b). Note that two of
the 160micron SCAN regions were observed in MIPS-914 and MIPS-916.
Since these tasks are repeated a number of times during IOC, we will observe
different regions of the sky each time. The tasks will check for possible
variations of quality of IC or saturation. This task will also be useful for
screening regions of the sky to obtain ICs in SIRTF routine operations.
The reduction was performed with the DAT programs. We used mips_sloper with
sensitive cosmic ray detection (-q option)
turning off the electronic non-linearity correction, mips_caler (using
the 160micron me_160_dark_CamK_26oct2003.fits)
and mips_enhancer with the following options:
verbose = 0
scale = 1.
filename = ic160_scan
prefix = ic_scan160
nXTile = 1
nYTile = 1
dark = 0
flat = 0
illumination_correction = 1
NormalizeInput = 1
SigmaCut = 3.0
SigmaTolerance = 0.25
MaxIterations = 10
StackSTDEV = 0
OutlierMinPoints = 3
QuartileFactor = 10
OverlapTolerance = 0.5
diagonistics = 1
WriteGeometry = 0
WriteOutlier = 0
WriteTiles = 0
FluxMean = 0
FluxMedian = 1
OverWrite = 1
distortion = 0
UseBoostFrame = 1
reject = 1
Note that we rejected the first DCE after the stim flash (reject = 1 option) and normalized
the input images (NormalizeInput = 1 option).
Figure1.
Comparison of 160micron Illumination Corrections obtained in PHOTOMETRY (left) and SCAN modes (right).
Both are displayed from z1=0. to z2=2.