As previously discussed, one day of observations in November has a corrupted calibration scan of Mars. We're attempting to use a central array beammap in which we have beammaps for three channels, and skydips to get the full array calibration.
The beammap gives the absolute calibration for 3 channels.
The skydip gives the relative calibration across the array.

What we're doing:
1. Indexing the central array beammap by hand (not properly done by the raster indexing).
2. Remove a source masked mean value from each subscan.
3. Make a channel map and fit a gaussian amplitude, holding the beam parameters equal to their average value over the A520 scans.

4. Measure the channel offsets across the array and calibrate using one of the absolute calibrated channels (will eventually use a combination).
.

Varied the source flag radius (kept above 1'), fitted polynomial order, and fitting radius. When we use a source flag of 2', 0th order polynomial and 5' fit radius for the absolute calibration, the array calibrations made using the 3 channels all agree to within 5% (1.5% agreement between channel 103 and 159).

5. Tested on a day with full mars calibration. (factor of 100 missing somewhere).

-- JamesKennedy - 08 Jul 2009

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This topic: APEX_SZ > WebHome > A520 > 2009-07-08 Topic revision: r3 - 2009-08-12 - JamesKennedy

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