The QMAP Information Page

Contents:

last updated: 08 May 1998

Logs

 
flight 1 flight 2
flight log xxx xxx
pointing status xxx xxx
CCD camera locks xxx xxx
uplink command log xxx
landing site map xxx xxx
 

Parameters

Current parameters files for

Map Orientation

The overall map orientation is illustrated in this coverage image from flight 1, channel Ka1.


This image shows the coverage as usual, but the flat background is replaced with the right ascension in hours.  Note that the Y axis is reversed.  Click on the image to get a postscript version of the plot.   Dark indicates small RA; bright indicates large RA.

Radiometry Offsets

Here are the mean LVDT 1 position as well as the radiometry offsets during the ncp blocks in both flights.  The radiometry offsets (with 160 independent pixels) were folded over the chopper position.
 
flight 1 flight 2 flight 2, zoomed
LVDT 1 LVDT 1
Ka 1/2 Ka 1/2 Ka 1/2
Q 1/2 Q 1/2 Q 1/2
Q 3/4 Q 3/4 Q 3/4
spline fits
    

Beam Images

These are PS files with individual and combined beam images.  For flight 1, the version without offset correction is shown as well.  All beam images are calibrated in mK and use the calibration below.
 
  flight 1 flight 2
radiometry offset:
corrected
uncorrected
uncorrected
Ka Ka1  Ka2 Ka comb Ka1  Ka2 Ka comb Ka1  Ka2 Ka comb
Q1/2 Q1  Q2 Q1/2 comb Q1  Q2 Q1/2 comb Q1  Q2 Q1/2 comb
Q3/4 Q3  Q4   Q3  Q4   Q3  Q4 Q3/4 comb
 

Beam Fits

These plots show the reliability of the beam fits as a function of window size.  The two fit modes differ in their use of a background model: mode 1 only uses offset+slope, whereas mode 2 uses offset+slope+curvature.  The fit window is restricted by one pixel in radius on each step; the points to the right of the plot are noisy, because the fit window does not cover the beam completely.  On the other hand, large windows are dominated by the large weight of the background and by some of the other point sources in the Galactic plane.
 
parameter
flight 1
flight 2
beam integral Ka 1/2 Q 1/2 Q 3/4 Ka 1/2 Q 1/2 Q 3/4
beam size (FWHM) Ka 1/2 Q 1/2 Q 3/4 Ka 1/2 Q 1/2 Q 3/4
chi-squared Ka 1/2 Q 1/2 Q 3/4 Ka 1/2 Q 1/2 Q 3/4

Calibration

Is based on Cas A, for which we present a slightly enhanced fit.  This fit uses all Baars data above 300 MHz and adds mm-wave points from Mezger et al. and Chini et al. as well as the 32 GHz point from Leitch et al. 1998.

Data Rejection

In the following table, I list the total number of frames rejected in the segments of each flight for each flag type.
 
  flight 1 flight 2
Flag ncp 1 ncp 2 total      ncp 1 ncp 2 ncp 3 total
manual     0       0
sigma in data     0       0
sigma in pointing 4 134 138 4   4 8
pointing is zero     0       0
projection out of bounds     0       0
calibration spike 336 54 390 398 208 92 698
   additional cal mask 504 81 585 398 208 92 698
bad CCD lock 311 143 454       0
high rms in data     0       0
 
total number of frames		  
16851		  
3281		  
20132		  
19901		  
10581		  
4571		  
35053
The additional cal mask is applied during the mapping stage, while the calibration spike flag is a marker that is applied during the cal spike analysis (and which always marks 2 consecutive frames).  The additional cal masks are applied for the 2 frames following the initial cal spike flag; in flight 1, the frame before is masked as well.

The criterion for cutting after cal spikes was to obtain a stable (i.e. time-independent) scan-syncronous radiometry offset.  The masks used are the minimum masks needed; the results do not change if the mask size increases.