Summary of Data Quality Observations of 01/11/95 ------------------------------------------------ Bob Sault, Robin Wark * In the DQO observations, we intend to either observe 1934-638 or 0823-500, whichever is the better night-time object. We are now entering the period of observing 0823-500. * A significant portion of the run ( > 4 hours) was lost because of high winds. A problem with turret rotation on antenna 1 meant that we lost an additional 30 minutes on that antenna. * 0823-500 has a confusing source about 10 arcmin to the south-west. Its apparent strength is 77 mJy at 1344 MHz and 21 mJy at 2368 MHz. Unfortunately the offset field was centred quite close to the confusing source. * 0823 appears to be polarised at the 1.5-2% level at 4800 and 8640. The reduction procedure did not account for this, and so the statistics for some of the polarised images is poorer than might have been hoped. * The blank field is quite good. The strongest source in the primary beam FWHM at 1344 MHz is about 5 mJy in apparent flux (there is an 8 mJy apparent flux source outside the primary beam FWHM). * Overall the data quality was good. The dynamic ranges reflect that 0823 is a third the strength of 1934, and more confused. * The gains determined from the on-axis observations of 0823 at 4800 and 8640 MHz were stable to about 1-2% over the course of the observation. The "4 sec jump" problem appears to be fixed. Array: 6A Fields: Calibrator 0823-500 Offset Calibrator 0823_a Blank Field 0823_b Frequencies: 1344 2368 4800 8640 MHz The offset calibrator field was offset in RA,DEC from 0823-500 by 0,420 arcsec at 1344 MHz 0,420 arcsec at 2368 MHz 0,120 arcsec at 4800 MHz 0,120 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% ---- --- --- --- --- 0823-500.1344 0.0% 0.0% 0.0% 0.0% 0823-500.2368 0.0% 0.0% 0.0% 0.0% 0823-500.4800 0.0% 0.0% 0.0% 0.0% 0823-500.8640 0.0% 0.0% 0.0% 0.0% 0823_a.1344 0.0% 0.0% 0.0% 0.0% 0823_a.2368 0.2% 0.0% 0.1% 0.1% 0823_a.4800 0.0% 0.0% 0.0% 0.0% 0823_a.8640 0.0% 0.0% 0.0% 0.0% 0823_b.1344 0.2% 0.2% 0.2% 0.1% 0823_b.2368 0.2% 0.2% 0.2% 0.2% 0823_b.4800 0.2% 0.0% 0.0% 0.2% 0823_b.8640 0.1% 0.0% 0.0% 0.0% ---------------------------------------------- Closure phase statistics for the point sources File Th.Phase Sigmas ---- -------- ------ 0823-500.1344 0.034 20.74 0823-500.2368 0.034 5.56 0823-500.4800 0.054 1.22 0823-500.8640 0.115 1.50 0823_a.1344 0.035 23.40 0823_a.2368 0.044 8.34 0823_a.4800 0.057 1.30 0823_a.8640 0.156 1.51 --------------------------------------- Post-reduction flagging statistics ---------------------------------- File XX% YY% XY% YX% ---- --- --- --- --- 0823-500.1344-cal 8.5% 8.5% 8.5% 8.5% 0823-500.2368-cal 3.9% 3.9% 3.9% 3.9% 0823-500.4800-cal 4.6% 4.6% 4.6% 4.6% 0823-500.8640-cal 3.3% 3.3% 3.3% 3.3% 0823_a.1344-cal 6.5% 6.5% 6.5% 6.5% 0823_a.2368-cal 0.9% 0.9% 0.9% 0.9% 0823_a.4800-cal 3.5% 3.5% 3.5% 3.5% 0823_a.8640-cal 6.9% 6.9% 6.9% 6.9% 0823_b.1344-cal 2.5% 2.5% 2.5% 2.5% 0823_b.2368-cal 2.3% 2.3% 2.3% 2.3% 0823_b.4800-cal 1.2% 1.2% 1.2% 1.2% 0823_b.8640-cal 2.4% 2.4% 2.4% 2.4% ======================================================================== File Th. RMS Sigmas D.R. Pk Val ---- ------- ------ ---- ------ 0823-500.1344-low.icln 2.82E-04 7.73 2496 5.439 0823-500.1344-low.qmap 2.82E-04 2.69 6 0.004 0823-500.1344-low.umap 2.82E-04 2.35 5 0.003 0823-500.1344-low.vmap 2.82E-04 1.64 5 0.002 0823-500.2368-low.icln 3.77E-04 3.10 4739 5.547 0823-500.2368-low.qmap 3.77E-04 3.09 9 0.010 0823-500.2368-low.umap 3.77E-04 2.66 7 0.007 0823-500.2368-low.vmap 3.77E-04 1.95 4 0.003 0823-500.4800-low.icln 3.87E-04 2.04 3913 3.086 0823-500.4800-low.qmap 3.87E-04 4.25 12 0.019 0823-500.4800-low.umap 3.87E-04 2.78 4 0.005 0823-500.4800-low.vmap 3.87E-04 1.27 4 0.002 0823-500.8640-low.icln 5.12E-04 0.63 4494 1.441 0823-500.8640-low.qmap 5.12E-04 1.91 8 0.008 0823-500.8640-low.umap 5.12E-04 1.26 4 0.003 0823-500.8640-low.vmap 5.12E-04 0.95 4 0.002 0823-500.1344-full.icln 1.10E-04 15.25 3230 5.432 0823-500.1344-full.qmap 1.10E-04 3.84 6 0.002 0823-500.1344-full.umap 1.10E-04 3.21 5 0.002 0823-500.1344-full.vmap 1.10E-04 2.20 5 0.001 0823-500.2368-full.icln 1.23E-04 5.23 8652 5.546 0823-500.2368-full.qmap 1.23E-04 4.99 16 0.010 0823-500.2368-full.umap 1.23E-04 4.27 15 0.008 0823-500.2368-full.vmap 1.23E-04 2.67 5 0.002 0823-500.4800-full.icln 1.04E-04 3.78 7841 3.084 0823-500.4800-full.qmap 1.04E-04 9.72 22 0.022 0823-500.4800-full.umap 1.04E-04 5.39 7 0.004 0823-500.4800-full.vmap 1.04E-04 1.41 5 0.001 0823-500.8640-full.icln 1.09E-04 1.71 7683 1.437 0823-500.8640-full.qmap 1.09E-04 4.67 18 0.009 0823-500.8640-full.umap 1.09E-04 2.72 5 0.002 0823-500.8640-full.vmap 1.09E-04 1.28 5 0.001 0823_a.1344-full.icln 1.09E-04 21.46 2057 4.797 0823_a.1344-full.qmap 1.09E-04 4.24 8 0.004 0823_a.1344-full.umap 1.09E-04 4.28 6 0.003 0823_a.1344-full.vmap 1.09E-04 2.09 12 0.003 0823_a.2368-full.icln 1.18E-04 11.04 3106 4.030 0823_a.2368-full.qmap 1.18E-04 25.15 20 0.059 0823_a.2368-full.umap 1.18E-04 22.96 10 0.026 0823_a.2368-full.vmap 1.18E-04 18.69 17 0.037 0823_a.4800-full.icln 1.02E-04 5.21 5311 2.828 0823_a.4800-full.qmap 1.02E-04 10.60 24 0.026 0823_a.4800-full.umap 1.02E-04 5.13 6 0.003 0823_a.4800-full.vmap 1.02E-04 1.42 4 0.001 0823_a.8640-full.icln 1.09E-04 3.06 3325 1.112 0823_a.8640-full.qmap 1.09E-04 10.42 20 0.023 0823_a.8640-full.umap 1.09E-04 5.99 9 0.006 0823_a.8640-full.vmap 1.09E-04 7.55 13 0.011 0823_b.1344-full.imap 1.02E-04 5.45 8 0.005 0823_b.1344-full.qmap 1.02E-04 1.05 5 0.001 0823_b.1344-full.umap 1.02E-04 1.08 5 0.000 0823_b.1344-full.vmap 1.02E-04 0.99 5 0.000 0823_b.2368-full.imap 1.15E-04 1.49 8 0.001 0823_b.2368-full.qmap 1.15E-04 1.00 5 0.001 0823_b.2368-full.umap 1.15E-04 0.97 5 0.001 0823_b.2368-full.vmap 1.15E-04 0.94 4 0.000 0823_b.4800-full.imap 1.00E-04 1.18 6 0.001 0823_b.4800-full.qmap 1.00E-04 1.09 5 0.001 0823_b.4800-full.umap 1.00E-04 1.08 5 0.001 0823_b.4800-full.vmap 1.00E-04 1.09 4 0.000 0823_b.8640-full.imap 1.07E-04 1.15 5 0.001 0823_b.8640-full.qmap 1.07E-04 1.09 4 0.001 0823_b.8640-full.umap 1.07E-04 1.05 4 0.000 0823_b.8640-full.vmap 1.07E-04 1.07 5 0.001 ======================================================================== 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.