*Calibrations*

The November 2008 calibration scans were too large to write to file during the APEXSZ operation and would cause a fits writer crash. To remedy this, the beam map halfscans were written as one scan - making our beam maps 141 scans instead of 1 scan with 141 halfscans. I'll call a group of 141 scans a full calibration scan.

Each full calibration scan contains at least one halfscan in which the bolometer data and telescope pointing data are not written properly - producing extra bolometer or pointing data points. The origin of this error isn't known - either the data isn't being interpreted properly, or one is being read out longer than the other. It occurs occationally, producing a matlab error message:

 
65536 had an error when processing
message: In an assignment A(I) = B, the number of elements in B and I mush be the same

I use the matlab pipeline function sourcecal.m to get the calibration data for these scans (ignoring the problem halfscans described above). The flux and beam parameter .dat files are stored as an attachment on this page.

Here is the beam sizes and positions from scan 65536

There are some problem beams. Here is the beammap from channel 69. The beammap doesn't look too bad, so we'll have to see why it's getting a big offset and small FWHM.

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to do:

1. Add skydip opacity measurements.
2. Check calibrations againts RCW38 beammaps.

-- JamesKennedy - 26 Mar 2009

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This topic: APEX_SZ > WebHome > A520 > 2009-03-26 Topic revision: r1 - 2009-03-26 - JamesKennedy

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