Calibrationtests June 2003

To see weather we can use RxH3 calibration measurements to find out whether the conditions are good enough to make a map we made long calibration measurements (2 times 300 seconds) at 160 GHz on 13 June (tau_cso 0.12-0.16), 29 June (tau_cso 0.125-0.13), and 30 June (tau_cso 0.084-0.087). Measurements were taken at the calibration position (483, 0) (flat in phase), and some at (0,0) (phase varies rapidly) at one frequency with a sampling rate of 15 msec.
Some measurements were taken at 80 GHz on 13 June (not shown here to avoid too much confusion).

Shown are plots of phase and amplitude versus time for the whole interval and for a smaller interval.
The order is:
phase 1306 (483,0) 600 seconds
phase 2906 (483,0) 600 seconds
phase 3006 (483,0) 600 seconds
phase 1306 (483,0) 40 seconds
phase 2906 (483,0) 40 seconds
phase 3006 (483,0) 40 seconds
phase 1306 (0,0) 600 seconds
phase 2906 (0,0) 600 seconds
phase 1306 (0,0) 40 seconds
phase 2906 (0,0) 40 seconds
then the same for amplitudes
The relative scale is the same for the different days.

After these calibrations we took maps at 80 GHz (13 June) and 160 GHz (29 and 30 June).
Below are the rms values derived from these maps.
The 80 GHz map value can be compared with numbers derived from a map in good weather on 9 April.

The maps of 13 June and 29 June show stripes and are not useful for dish adjustments.
The map of 30 June is good (but the dish shows some systematic deviations in the upper left).

The scatter in the calibration measurements is worse on 13 June when the weather was very unstable.
On 29 and 30 June the total scatter in the calibration measurements seems similar, but on 30 June there are less systematic longer-scale variations (times of several seconds).

80 GHz 13 June 2003 20030613-135640 tau_cso 0.12-0.16
Total errors on mean aperture:
ring: 1 2 3 4 5 6 7 total
rms: 28.7 21.8 20.6 24.6 30.6 38.4 48.9 39.2
Taper = 10 dB, Ruze illumination-weighted rms = 37.7 micron

for comparison - 80 GHz map in very good weather gives:
Total errors on mean aperture:
ring: 1 2 3 4 5 6 7 total
rms: 27.3 18.4 19.2 21.9 24.8 29.2 37.9 28.7
Taper = 10 dB, Ruze illumination-weighted rms = 27.6 micron

160 GHz 29 June 2003 20030629-233840 tau_cso 0.125 - 0.13
Total errors on mean aperture:
ring: 1 2 3 4 5 6 7 total
rms: 27.3 22.1 19.3 22.9 24.1 28.3 34.4 28.3
Taper = 10 dB, Ruze illumination-weighted rms = 27.8 micron

160 GHz 30 June 2003 20030630-235645 tau_cso 0.084 - 0.087
Total errors on mean aperture:
ring: 1 2 3 4 5 6 7 total
rms: 23.1 20.3 17.4 21.5 23.9 24.6 32.5 25.3
Taper = 10 dB, Ruze illumination-weighted rms = 24.6 micron

Last modified: 2 July 2003
Jan Wouterloot