Summary of the DQO observations of 17-Oct-95 ============================================ Bob Sault, Robin Wark * The observing run did not appear to suffer from the (pseudo-) Early/Normal problems that beset the array soon after the run. All the same, there was a larger amount than normal of bad 6 and 3 cm data because of other array problems that we being fixed at the time. * Dynamic ranges for this observation were poorer than some previous runs. In part this appears to be a result of poorer observing conditions late in the run near when 1934 set. Also having to rerun CACAL twice during the observation (as antennas came back into service) undoubtedly did not help. The closure phases and the ability to reach thermal noise in the blank fields were similar or better than previous runs. * Interference again showed up at approx 1320 MHz as well as 1381 MHz. * 6-cm off-axis polarimetric response agreed (surprisingly) well with a model we now have (after I corrected a mistake in what I was predicting!!). The pointing centre for the 6/3 offset field observation was changed for this run to be somewhat more testing. * We have compared the cycle-to-cycle jitter in the noise-source XY phase measurements with the observations to test the hypotheses that this jitter either reflects real phase changes in the system or reflects an error in the measurement. Given the thermal noise limits of the noise-source and astronomical measurements, we find that this cycle-to-cycle jitter is consistent with being real, and inconsistent with being an error (i.e. the jitter in the XY phase measurements derived astronomical and by the noise-source track reasonably). Tests earlier in the week by mjk, rjs and grg seemed to rule out the L2 oscillator and the receiver as the source of the XY phase jitter. Array: 1.5D Fields: Calibrator 1934-638 Offset Calibrator 1934_a Blank Field 1934_b Frequencies: 1344 2368 4800 8640 MHz The offset calibrator field was offset in RA,DEC from 1934-638 by -420,0 arcsec at 1344 MHz -420,0 arcsec at 2368 MHz -300,0 arcsec at 4800 MHz -300,0 arcsec at 8640 MHz See the end of this document for an explanation of terms and the filenaming convention. ------------------------------------------------------------------------ Flagging statistics after ATLOD ------------------------------- File XX% YY% XY% YX% ---- --- --- --- --- 1934-638.1344 2.2% 2.2% 2.3% 2.2% 1934-638.2368 0.2% 0.1% 0.2% 0.2% 1934-638.4800 6.1% 6.1% 6.1% 6.1% 1934-638.8640 6.0% 6.0% 6.0% 6.0% 1934_a.1344 1.7% 1.7% 1.7% 1.7% 1934_a.2368 0.1% 0.0% 0.0% 0.1% 1934_a.4800 1.4% 1.4% 1.4% 1.4% 1934_a.8640 1.4% 1.4% 1.4% 1.4% 1934_b.1344 1.8% 1.8% 1.9% 1.8% 1934_b.2368 0.3% 0.3% 0.2% 0.4% 1934_b.4800 1.4% 1.5% 1.4% 1.5% 1934_b.8640 1.4% 1.5% 1.4% 1.5% ---------------------------------------------- Closure phase statistics for the point sources ---------------------------------------------- File Th.Phase Sigmas ---- -------- ------ 1934-638.1344 0.012 19.92 1934-638.2368 0.017 4.65 1934-638.4800 0.032 1.53 1934-638.8640 0.064 2.05 1934_a.1344 0.013 15.15 1934_a.2368 0.021 4.52 1934_a.4800 0.052 1.35 1934_a.8640 0.522 1.07 --------------------------------------- Post-reduction flagging statistics ---------------------------------- File XX% YY% XY% YX% ---- --- --- --- --- 1934-638.1344-cal 20.7% 20.7% 20.7% 20.7% 1934-638.2368-cal 7.4% 7.4% 7.4% 7.4% 1934-638.4800-cal 11.9% 11.9% 11.9% 11.9% 1934-638.8640-cal 10.3% 10.3% 10.3% 10.3% 1934_a.1344-cal 10.1% 10.1% 10.1% 10.1% 1934_a.2368-cal 0.2% 0.2% 0.2% 0.2% 1934_a.4800-cal 2.9% 2.9% 2.9% 2.9% 1934_a.8640-cal 3.7% 3.7% 3.7% 3.7% 1934_b.1344-cal 5.4% 5.4% 5.4% 5.4% 1934_b.2368-cal 3.0% 3.0% 3.0% 3.0% 1934_b.4800-cal 6.3% 6.3% 6.3% 6.3% 1934_b.8640-cal 3.2% 3.2% 3.2% 3.2% ======================================================================== File Th. RMS Sigmas D.R. Pk Val ---- ------- ------ ---- ------ 1934-638.1344-low.icln-x 2.11E-04 10.22 6975 15.005 1934-638.1344-low.qmap 2.11E-04 6.93 4 0.006 1934-638.1344-low.umap 2.11E-04 6.09 5 0.006 1934-638.1344-low.vmap 2.11E-04 3.83 5 0.004 1934-638.2368-low.icln-x 2.63E-04 11.99 3669 11.583 1934-638.2368-low.qmap 2.63E-04 3.92 5 0.005 1934-638.2368-low.umap 2.63E-04 3.95 4 0.005 1934-638.2368-low.vmap 2.63E-04 3.61 4 0.004 1934-638.4800-low.icln-x 2.72E-04 4.30 4975 5.827 1934-638.4800-low.qmap 2.72E-04 1.53 5 0.002 1934-638.4800-low.umap 2.72E-04 1.32 4 0.001 1934-638.4800-low.vmap 2.72E-04 1.29 5 0.002 1934-638.8640-low.icln-x 3.05E-04 1.98 4692 2.841 1934-638.8640-low.qmap 3.05E-04 0.99 5 0.001 1934-638.8640-low.umap 3.05E-04 1.04 4 0.001 1934-638.8640-low.vmap 3.05E-04 1.12 4 0.001 1934-638.1344-full.icln-x 9.40E-05 18.16 8786 14.997 1934-638.1344-full.qmap 9.40E-05 8.92 4 0.004 1934-638.1344-full.umap 9.40E-05 8.19 5 0.004 1934-638.1344-full.vmap 9.40E-05 6.06 4 0.002 1934-638.2368-full.icln-x 1.01E-04 16.47 6938 11.582 1934-638.2368-full.qmap 1.01E-04 5.52 5 0.003 1934-638.2368-full.umap 1.01E-04 5.53 4 0.002 1934-638.2368-full.vmap 1.01E-04 5.16 5 0.003 1934-638.4800-full.icln-x 8.38E-05 8.16 8515 5.825 1934-638.4800-full.qmap 8.38E-05 1.69 6 0.001 1934-638.4800-full.umap 8.38E-05 1.59 5 0.001 1934-638.4800-full.vmap 8.38E-05 2.09 5 0.001 1934-638.8640-full.icln-x 8.34E-05 4.18 8140 2.839 1934-638.8640-full.qmap 8.34E-05 1.20 5 0.000 1934-638.8640-full.umap 8.34E-05 1.24 6 0.001 1934-638.8640-full.vmap 8.34E-05 1.50 6 0.001 1934_a.1344-full.icln-x 9.30E-05 35.87 3962 13.221 1934_a.1344-full.qmap 9.30E-05 12.74 11 0.013 1934_a.1344-full.umap 9.30E-05 13.10 7 0.009 1934_a.1344-full.vmap 9.30E-05 5.57 8 0.004 1934_a.2368-full.icln-x 9.75E-05 26.84 3229 8.451 1934_a.2368-full.qmap 9.75E-05 75.60 16 0.119 1934_a.2368-full.umap 9.75E-05 72.19 7 0.050 1934_a.2368-full.vmap 9.75E-05 38.56 17 0.064 1934_a.4800-full.icln-x 8.49E-05 10.41 3315 2.931 1934_a.4800-full.qmap 8.49E-05 11.50 28 0.027 1934_a.4800-full.umap 8.49E-05 2.45 7 0.002 1934_a.4800-full.vmap 8.49E-05 1.81 11 0.002 1934_a.8640-full.icln-x 8.52E-05 1.75 1946 0.290 1934_a.8640-full.qmap 8.52E-05 16.37 23 0.033 1934_a.8640-full.umap 8.52E-05 6.10 7 0.003 1934_a.8640-full.vmap 8.52E-05 7.58 16 0.010 1934_b.1344-full.imap 9.28E-05 7.00 8 0.005 1934_b.1344-full.qmap 9.28E-05 1.62 4 0.001 1934_b.1344-full.umap 9.28E-05 1.10 4 0.000 1934_b.1344-full.vmap 9.28E-05 1.03 4 0.000 1934_b.2368-full.imap 1.01E-04 2.15 5 0.001 1934_b.2368-full.qmap 1.01E-04 1.06 4 0.000 1934_b.2368-full.umap 1.01E-04 1.03 5 0.000 1934_b.2368-full.vmap 1.01E-04 1.01 5 0.000 1934_b.4800-full.imap 8.86E-05 1.10 10 0.001 1934_b.4800-full.qmap 8.86E-05 1.00 4 0.000 1934_b.4800-full.umap 8.86E-05 1.01 5 0.000 1934_b.4800-full.vmap 8.86E-05 0.97 4 0.000 1934_b.8640-full.imap 8.70E-05 1.08 5 0.000 1934_b.8640-full.qmap 8.70E-05 1.03 4 0.000 1934_b.8640-full.umap 8.70E-05 1.01 4 0.000 1934_b.8640-full.vmap 8.70E-05 0.98 5 0.000 ======================================================================== Explanation of Terms: --------------------- XX%,YY%,XY%,YY% Percentage of XX, XY, YX and YY correlations flagged (excluding on-line flagging and shadowing). Th.Phase The theoretical closure phase (in degrees) based on thermal noise arguments (for the 5-minute time averaging used). Th. RMS The theoretical RMS in an image based on thermal noise arguments. Sigmas The factor by which the relevant meausre exceeds either of the above two theoretical levels. Ideally this should be 1. D.R. Dynamic range of an image, defined as the ratio of the peak absolute value divided by the RMS. For the CLEANed Stokes-I images of the calibrators, the RMS is evaluated outside the inner quarter of the image. Otherwise the RMS is evaluated over the entire image. Pk Val Peak value in an image in Jy. Explanation of File names: -------------------------- File names are of the form FIELD.FREQ Raw visibility data, giving the field name and observing frequency. FIELD.FREQ-cal Calibrated/flagged visibility data. FIELD.FREQ-low.TYPE Low resolution image, imaging the entire primary beam. TYPE gives the Stokes parameter and whether the image is CLEANed ("cln") or a dirty image ("map"). FIELD.FREQ-full.TYPE Full resolution image, but imaging only a subportion of the primary beam. TYPE is as above.