LITTLE THINGS AIPS Reduction of DDO165, C config.: VLA Obs. of 16 of January 1991 ===================================================================== calibration recipe v. 2.0: mrupen 10oct08 calibration recipe v. 2.1: mrupen 13oct08 calibration recipe v. 2.1.update: Dana Ficut Vicas 29 Oct 08 (new adverbs in Aips) calibration recipe v. 2.2: Dana Ficut Vicas 11Dec 08(tiny bits) calibration recipe v. 2.3: Dana Ficut Vicas 11 Feb 09(UVCOP ambiguities) calibration recipe v. 2.4: Dana Ficut Vicas 3 Mar 09(team raised issues) calibration recipe v. 2.5: Dana Ficut Vicas 23 September 2009 (no smoothing with WIPER on the source data) Latest update: 3rd March 2009 Data reduced by Dana Ficut Vicas, Hertfordshire 20 of July 2010 Suggestion: STARTING with D ARRAY and then working through C array and B array is recommended. D array data will allow you to have a look at the whole field ( the strong continuum sources that might give problems will be obvious here), is more stable and will give you the best feel for the data. The recipe lists the B-array reduction, but obviously the same steps apply to all configurations. 0. Basic stuff B configuration From observing log (available online at http://www.vla.nrao.edu/cgi-bin/oplogs.cgi): * Wind/API rms phase/clouds: yy:yy 1-4 m/s 80-100% cumuloform clouds * Ant 27 weather problems 1. FILLM executed on 20 of July 2010 a. Request archive data: copy public project data : AH927 from this archive file : /home/archive_VLA6/files/2008-03/vla2008-03-23.dat    to this output file : /home/e2earchive/AH927_AM080323.xp1 copy public project data : AH927 from this archive file : /home/archive_VLA6/files/2008-04/vla2008-04-14.dat    to this output file : /home/e2earchive/AH927_AU080414.xp1 copy public project data : AH927 from this archive file : vla2008-07-07.dat to this output file : /home/e2earchive/AH927_BF080707.xp2 copy public project data : AH927 from this archive file : vla2008-07-31.dat to this output file : /home/e2earchive/AH927_BS080731.xp1 copy public project data : AH927 from this archive file : /home/archive_VLA6/files/2008-07/vla2008-07-31.dat    to this output file : /home/e2earchive/AH927_BS080731.xp1 b. FILLM -> DDO165-D1.CH 0.1, DDO165-C3.LINE.1 default FILLM datain 'ARCHIVE:DDO165/Archive/AP198_A910116.xp band 'l';vlaobs 'AP198'; doall -1 ; qual 5 $ restricts FILLM to the galaxy+calibrators of interest nfiles 0; ncount 2 $ read one filetget fillm, outna 'ddo165-C3' outdisk 1; outseq 0 douvcomp= -1 $ allow channel/IF-dependent weights doweight 10 $ use memo 108 weights (i.e., put weights in 1/Jy^2) bparm= -1,-1 $ avoid opacity & gain corrections cparm 0 cparm(4)=25.1 $ one needs to explicitly flag shadowed antennas $ since the ModComps were retired on 27 June 2007 $ this requires FILLM in 31DEC08 after 18Nov08 MNJ cparm(7)= -1 $ assigns new FREQID if frequency changes by more than $ the max. Doppler shift between sources 180 degrees $ apart. Setting this to -1 forces all data to have same $ FREQID. doconcat=-1 $ Change this to DOCONCAT=1 to add data to an existing file ***N.B. FILLM's channel 0 will ONLY be used for initial flagging. We're quite paranoid here. 2. TASAV -> LINSAV.1 executed on 20 of July 2010 ***We TASAV right away, because VLANT changes the AN table. Did I mention we're paranoid? default TASAV outna 'D165-3BeTaC outcla 'LINSAV' outdi 2 $ Ideally set this to a different disk from indisk, $ in case of disk crashes getn *.LINE 3. UVCOP -> LINCOP.1 executed on 20 of July 2010 ***Discard the first and last channels: 1st and last 10 channels if 127 channels total 1st and last 20 channels if 255 channels total ***We discard these Evil Channels because (1) they're pretty much useless; (2) they seem to confuse BPASS (which takes the solution from channel N as the initial guess for channel N+1); (3) their noise characteristics are quite different from the rest of the channels, which can be confusing e.g. in clipping and imaging. default UVCOP outcla 'LINCOP' bchan 11; echan 127-10 $ Use bchan 21 ; echan 255-20 if 255 channels total uvcopprm 0 uvcopprm(4) 1 $ report progress getn *.LINE ***From now on we operate on LINCOP data unless otherwise specified. 4. LISTR/SCAN --> DDO165-D1.listr ***We do this before VLANT because we need to know FREQIDs for VLANT default LISTR optype 'SCAN' docrt 132 getn *.LINCOP --> uhppc51 LISTR(31DEC08) 524 20-JUL-2010 13:26:54 Page 1 File = DDO165-C3 .LINCOP. 1 Vol = 3 Userid = 524 Freq = 1.420497397 GHz Ncor = 2 No. vis = 38870 Scan summary listing Scan Source Qual Calcode Sub Timerange FrqID START VIS END VIS 1 1358+624 : 0005 C 1 0/03:10:45 - 0/03:13:45 1 1 2275 2 U08201 : 0005 1 0/03:17:00 - 0/03:51:00 1 2276 8593 3 1358+624 : 0005 C 1 0/03:54:45 - 0/03:58:15 1 8594 10868 4 1358+624 : 0005 C 1 0/08:23:15 - 0/08:26:15 1 10869 13299 5 U08201 : 0005 1 0/08:31:00 - 0/09:01:00 1 13300 18915 6 1358+624 : 0005 C 1 0/09:03:45 - 0/09:06:15 1 18916 20670 7 1328+307 : 0005 C 1 0/09:26:15 - 0/09:37:15 1 20671 28743 8 1358+624 : 0005 C 1 0/11:00:15 - 0/11:02:45 1 28744 30823 9 U08201 : 0005 1 0/11:05:00 - 0/11:37:00 1 30824 36764 10 1358+624 : 0005 C 1 0/11:40:15 - 0/11:42:45 1 36765 38870 Source summary Velocity type = 'BARYCENT' Definition = 'OPTICAL ' ID Source Qual Calcode RA(1950.0) Dec(1950.0) IFlux QFlux UFlux VFlux No. vis 1 1358+624 : 0005 C 13:58:58.3600 62:25:06.700 0.000 0.000 0.000 0.000 12922 2 U08201 : 0005 13:04:39.4000 67:58:16.000 0.000 0.000 0.000 0.000 17875 3 1328+307 : 0005 C 13:28:49.6570 30:45:58.640 0.000 0.000 0.000 0.000 8073 ID Source Freq(GHz) Velocity(Km/s) Rest freq (GHz) 1 1358+624 1.4205 -10.0000 1.4204 2 U08201 1.4205 -10.0000 1.4204 3 1328+307 1.4188 360.0000 1.4204 Frequency Table summary FQID IF# Freq(GHz) BW(kHz) Ch.Sep(kHz) Sideband 1 1 1.42049740 1306.1525 12.2070 1 AIPS 1: Resumes 90 min on source 5. VLANT -> AN/1, CL/2 executed on 20 of July 2010 ***Note that VLANT can be run only for data observed from 1992 onwards. Data earlier than 1991 produce the following error message: VLANT1: Task VLANT (release of 31DEC07) begins VLANT1: ANT DATA UNAVAILABLE FOR YEAR 1991 DATA START WITH 1992 VLANT1: Purports to die of UNNATURAL causes For earlier data we skip baseline corrections entirely, and hope for the best. If there are clear and systematic phase gradients with time, consult the baseline corrections at http://www.vla.nrao.edu/astro/archive/baselines/ and apply corrections via CLCOR (which is basically what VLANT does). ***10oct08: Currently VLANT works on only one FREQID at a time. We therefore have to run VLANT multiple times for data with multiple FREQIDs. Unfortunately VLANT (1) produces a new CL table every time, and (2) updates the AN table positions every time as well. : CL tables: I'd like to maintain the convention that CL/1 is the original CL table and CL/2 has all the corrections that should have been applied on-line but weren't -- mainly, antenna position corrections. For multiple FREQIDs therefore this recipe calls for deleting the intermediate CL tables created by VLANT, using the rather clumsy mechanism of TASAVing to a temporary file, deleting the original CL tables, and copying the latest one back from the TASAV'd data set. Blah. : AN table: For now, this recipe resets to the original AN table just before running VLANT the last time. This means that only one run of VLANT updates the AN entries, leading to a correct AN table as needed for (e.g.) UVFIX. I've e-mailed DAIP to see about fixing all this, by allowing FREQID= -1 to mean "calculate corrections for all FREQIDs" (currently FREQID= -1 is reset to FREQID= 1). We'll see what Eric says. #####VLANT no longer has freqid as a parameter. 5a. default VLANT getn *.LINCOP Data is from 1991!!! 6. PRTAN AN/1 default PRTAN docrt 132 getn *.LINCOP Location Of VLA Antennas N18 (15) N16 ( 8) N14 ( 6) N12 (27) N10 (13) N8 (21) N6 ( 2) N4 (17) N2 (26) ( 3) W2 E2 ( 4) (19) W4 E4 (18) (28) W6 E6 ( 5) ( 9) W8 E8 (23) (10) W10 E10 (16) (11) W12 E12 (25) ( 1) W14 E14 (14) (20) W16 E16 (22) (12) W18 E18 ( 7) VLA:_OUT (24) VPT:_OUT (29) AIPS 1: Resumes ***To choose the reference antenna the following algorithm should be followed: 1. should be present throughout the run 2. should be on an "inner" pad, but NOT N1/E1/W1 (to avoid shadowing) 3. NOT on the master pad (since those are always weird) 4. NOT an EVLA antenna (since those are often weird) 5. try to avoid the north arm in the smaller configurations (to avoid shadowing) 6. NOT listed in any interesting way in the log file (to avoid problems with the reference antenna) 7. preferably consistent with other recent runs 8. should be a fairly stable antenna (can't tell until TVFLG/CALIB of course...) ===> Refant: 5 $ W2 7. Calibrators ***Check out the calibrators in the on-line calibrator manual: http://www.vla.nrao.edu/astro/calib/manual/index.shtml ***Max baseline at 21 cm in B array is 54.3 klambda C array is 16.2 klambda D array is 4.9 klambda primary (flux/bandpass) calibrators: 1328+307=1331+305=3C286 ***You can ignore the uv-ranges for these, since there are now models for the most important ones. secondary (gain) calibrator: 1358+624 1400+621 J2000 C 14h00m28.6526s 62d10'38.526" 1358+624 B1950 C 13h58m58.3600s 62d25'06.700" ----------------------------------------------------- BAND A B C D FLUX(Jy) UVMIN(kL) UVMAX(kL) ===================================================== 20cm L P P P P 4.40 ===> secondary cal --- NO restrictions 7b. SETJY -> SU/1 executed on 20 of July 2010 ***Set aparm(2) to corespond to date of observation. If date <1990 aparm(2)=3 If 19921998 aparm(2)=0 ***We need to enter a flux density for each primary (flux) calibrator. ***If we have more than one FREQID, we assume that the frequency offsets used are small, so that the flux densities of the flux calibrators are nearly the same for each FREQID. Typical frequency offsets are of order the bandwidth, +/-3 MHz; at 1420 MHz, for a worst-case spectral index of -1, this leads to an error of 2*3 MHz/1420 MHz= 0.4% -- not worth worrying about. So, we use any FREQID which covers all primary flux calibrators. If flux calibrator A is observed only with FREQID 1, while flux calibrator B is observed only with FREQID 2, we have to run SETJY twice: default SETJY sources '1328+307','' $ primary (flux) calibrator A optype 'CALC'; freqid=1 $ FREQID for A aparm 0,3 $ data taken on 1991 getn *.LINCOP; / Flux calculated using known spectrum uhppc5> SETJY1: BIF = 1 EIF = 1 /Range of IFs uhppc5> SETJY1: '1328+307 ' IF = 1 FLUX =14.7328 (Jy calcd) uhppc5> SETJY1: / Using (1990) VLA or Reynolds (1934-638) coefficients 7c. CALRD executed on 20 July 2010 ***Read in models of flux density calibrators: default CALRD object '3c286';band 'L'; Eposwitched it!!! ***Note: These models are in J2000 coordinates. If your data are in B1950, change the model images to B1950 with EPOSWTCH. We will later use UVFIX to fix the uv-data. Both in J2000!!! 8. PRTUV (used to find integration times on calibrators & sources) default PRTUV cparm 0; cparm(9)=103 $ Pick a baseline -- here, baseline 1-3 docrt 132 getn *.LINCOP --> calib: 30s source: 120s 9. UVFLG -> FG/1 executed on 20 July 2010 ***We toss the EVLA-EVLA baselines, to avoid dealing with aliasing. There should still be plenty of VLA-EVLA baselines to allow antenna-based solutions for the EVLA...but keep an eye out for oddities (e.g., in BPASS)! default UVFLG outfgver 1;opcode 'flag';reason 'EVLA' getn *.CH0 $ Note that we use FILLM's CH0 for initial flags -- we'll $ TACOP later. antenna=EVLA;baseline=EVLA; ***NOTE!!! do NOT run UVFLG if EVLA=0 (try PRINT EVLA to check) -- otherwise you'll delete ALL of your data. NOT NEEDED!Data is from the archives!!! 10. TVFLG -> FG/1 executed on 20 July 2010 ***Again, we *only* use the original CH 0 from FILLM for initial flagging. Here we flag calibrators only, to remove any gross, obvious problems. - Check the first scan carefully -- often the system isn't "organized" on this first scan - On-line flagging isn't as reliable as in the old days, so there are plenty of hot pixels and hiccups. - We are NOT quacking, because (1) FILLM's NX table isn't correct; (2) QUACK flags data from the beginning-of-scan, whereas we want to flag data from antennas-on-source. default TVFLG calcode '*' $ calibrators only docat -1 $ avoid saving temporary files dohist -1 $ avoid creation of history entries Freqid 1 $ must step through all FREQIDs! docalib -1 flagver 1;outfgver 1 $ keep all flags in FG/1 dparm 0 dparm(3) 1 $ show baselines twice, to treat all antennas identically -- $ this displays baseline 27-1 as well as 1-27 dparm(6)=30 $ time resolution: should be set to the calibrators' integration $ time, in seconds getn *.CH0 $ note this is the ONLY time we use FILLM's Channel 0! ***Within TVFLG: - Set useful defaults: SMOOTH=1 to avoid averaging date before displays SCAN= 20 to use a long time for median filters (AMP/PH DIFF) FLAG ALL CHANNELS FLAG STOKES FULL (usually -- sometimes you'll want NORR or NOLL) ***If individual Stokes need to be flagged, make sure you set the STOKES FLAG to correspond to the polarization that is displayed on the TV SWITCH SOURCE FLAG to ONE-SOURCE to avoid inadvertantly flagging your galaxy (though sometimes you'll want to of course) - Be sure to inspect BOTH polarizations! ***We suggest the following steps: - Set the above defaults - Flag first integration in every scan (manual QUACK) -- this should be the first integration AFTER most antennas are on-source, which is why we can't use the usual QUACK. - Inspect the following: AMPLITUDE to check for missing records or antennas AMP DIFF to check for variable gains PHS DIFF to check for variable atmosphere/gains - If your data set is in D array(if your source is southern than also check for this problem in the C array) than keep an open eye for solar interference. It will be obvious if in TVFLG you choose a SORT BY BASELINE display, showing you how the short baselines behave,the ones affected by solar interference.If solar interference is affecting your data than in CALIB you should use a UVRANGE. ***Note: occasionally, flagging using UVFLG can be more straightforward (e.g., deleting an antenna). Example: default UVFLG antenna 21,0 stokes 'll' $ the antenna which "jumped" opcode 'FLAG' reason 'bad BP' outfgver 1 getn *.CH0.1 NOT NEEDED!!! 10b. TABED FG/1 executed on 20 July 2010 ***Here we TABED the CH 0 flags to LINCOP (with FREQID= -1). After this we're done with FILLM's channel 0. default TABED opty 'repl' inext 'fg' inver 1 ; outver 1; bcount 1;ecount 0 ; $until recently there was a parameter called $ncount which is no longer there aparm 0 aparm(1) 3 $ Changing column 3 = FREQID keyval= -1,0 $ ...to FREQID= -1 getn *.CH 0 getona *.LINCOP --> LINCOP FG/1 I used TACOP here, for some reason TABED creates an unsuable FG table. 11. BPASS ***This is a first-order BPASS leading to a new Channel 0. The goal is to avoid closure errors in Channel 0 calibration due to huge delays (phase slopes) on VLA-EVLA baselines. We divide each visibility by the vector average of the inner 3/4 of the band (i.e., an on-the-fly channel 0). Thus we remove source structure (tho' getting the weights wrong) and take care of the amplitude scale. ***There is a split here between the easy case (one FREQID for all sources) and the Galactic HI case (multiple FREQIDs, usually different for the bandpass calibrator and the galaxy (and phase calibrator)). Check LISTR/SCAN to see which you're doing. 11b. BPASS: Multiple FREQIDs -> BP/1,2,3 executed on 15 July 2010 ***The overall plan here is as follows (assuming FREQIDs 1 and 2 refer to the offset [bandpass calibrator] frequencies, and FREQID 3 refers to that of the galaxy & phase calibrator): (1) run BPASS once for FREQID=1 (-> BP/1) and once for FREQID=2 (-> BP/2). (2) check both BP tables with POSSM. They should look virtually identical. (3) If they do appear virtually identical, we concatenate them: (a) write out both tables [TBOUT], (b) concatenate the two [vi/emacs], (c) read them back in [TBIN] as BP/3, (4) If they do NOT appear identical, there is Something Wrong. The case we've come across involves the use of a front-end filter combined with the use of unexpected LOs (see Adrienne's note), so that one FREQID was observed through the edge of the filter. The resulting bandpasses show a strong slope in the amplitude gains for most VLA antennas. So far we've seen this only for central frequencies around 1423 MHz. In this case, simply copy the "good" BP table to BP/3 using TACOP. (5) modify BP/3 to refer to FREQID=3 [TABED]. ***It is a VERY good idea to use POSSM carefully throughout to be sure you're doing what you think you're doing. 11b1. BPASS FREQID 1 -> BP/1 executed on 12 July 2010 default BPASS calsour '1328+307','' $ Select bandpass calibrators docal 1 ; gainuse 1 $ apply VLANT changes. Probably irrelevant. flagver 1 $ apply initial flags refant 5 $ Change this to your refant Qual -1 solint 0 $ one solution per scan minamper 7 ; minphser 7 $ report closures > 7%/7d smooth 0 $ no smoothing soltype '' ; weightit 0 $ L1, L1R, etc. seem _less_ stable -- weird bpassprm 0 bpassprm(5) 0 $ derive "channel 0" on a record-by-record basis -- $ more biased than averaging first, but avoids $ some subtle pitfalls (see EXPLAIN file) bpassprm(2) 1 $ some closure info is printed bpassprm(6) 2 $ print avg. closure errors > 2% bpassprm(7) 2 $ print avg. closure errors > 2d ichansel 0 $ derive channel 0 from inner 3/4 of the band freqid 1 $ 1st offset FREQID getn *.LINCOP --> BP/1 11c. POSSM to check BP table 11c1. Plot BP table itself default POSSM $ to check BPASS results flagver 1 aparm 0, 1, 0.7, 1.3, -180, 180, 0, 2, 0, 0 $ Plot BP, with amp/ph ranges source '1328+307','' $ POSSM doesn't work with $ source '' for some reason! solint -1 $ Separate plots for each scan nplots 9 $ 9 plots per page bparm 0 docal 1 ; gainuse 1 ; doband 1 dotv 1 freqid 1; bpver 1 $ for no-FREQID data sets getn *.LINCOP tvinit 11c2. Apply BP table to 2ndary calibrator & plot individual baselines default POSSM flagver 1 aparm 0 $ Plot data solint -1 $ Separate plots for each scan nplots 9 $ 9 plots per page aparm 0 aparm(1) 1 $ vector average source='1358+624','' $ Secondary (phase) calibrator docal 1 ; gainuse 1 ; doband 1 $ average all BP entries dotv 1 freqid 1; bpver 1 $ for multiple-FREQID data sets getn *.LINCOP tvinit 11c3. Apply BP table to 2ndary calibrator & vector average all data default POSSM flagver 1 aparm 0 $ Plot data solint 0 $ average all time nplots 0 $ average all baselines aparm 0 aparm(1) 1 $ vector average source='1358+624','' $ Secondary (phase) calibrator docal 1 ; gainuse 1 ; doband 1 $ average all BP entries dotv 1 freqid 1; bpver 1 $ for multiple-FREQID data sets getn *.LINCOP tvinit ***This plot should be flat in both amp. and phase as a function of frequency, with no slope.. If some channels are off, note which ones those are and keep an eye out for interference or other bad data. If there are large errors consider running BPASS on the secondary calibrator and using that to correct the galaxy. Note that this will be somewhat painful since AIPS does not allow incremental BP tables -- unlike SN or CL tables. Sigh. 12. AVSPC -> NEWCH0.1 (2,3) executed on 20 July 2010 ***AVSPC must be run once for each FREQID (unfortunately FREQID=-1 purports to work, but creates an empty data set). This entails some nasty bookkeeping for data sets with multiple FREQIDs. Here I assume we have one or three FREQIDs. If BPASS checks above show that one FREQID is useless, you should ignore that one entirely in this and all subsequent processing. ***We will use these NEWCH0 files for (1) further flagging, and (2) time-dependent gain calibration. 12a. FREQID=1 --> NEWCH0.1 default AVSPC docalib -1;gainuse 0; flagver -1 $ do NOT apply flags doband 1 freqid 1; bpver 1 $ for multiple-FREQID data sets getn *.LINCOP outname inna ; outcl 'NEWCH0' --> NEWCH0.1 12d. LISTR/SCAN ***It is a VERY good idea to run LISTR/SCAN on each of the NEWCH0 data sets at this point, to be sure each has the data you expect. 13. TABED LINCOP FG/1 -> NEWCH0 FG/1 ***We use TABED to set FREQID to -1 (apply to all FREQIDs) in the FG table, since AVSPC will change all FREQIDs to 1 in the NEWCH0 data sets. 13a. NEWCH0.1 default TABED opty 'repl' inext 'fg' inver 1 ; outver 1 aparm 0 aparm(1) 3 $ Changing column 3 = FREQID keyval= -1,0 $ ...to FREQID= -1 getn *.LINCOP getona *.NEWCH0.1 --> NEWCH0.1, FG/1 14. CALIB -> NEWCH0.1(,2,3) SN/1 executed on 20 July 2010 ***If we only have one FREQID, all CALIBs are run on the same NEWCH0.1 . If we have multiple FREQIDs, CALIBs for a given source must be run for all NEWCH0.1,2,3 in which that source appears (probably easiest to check with LISTR/SCAN). ***Note: if 'SN' table must be destroyed: task 'extdest'; inext 'sn'; invers 0 ***If solar interference is affecting your data than in CALIB you should use a UVRANGE. The worst case scenario, baselines up to a distance of 1 kilolambda could be afected, while in the best case scenario baselines are affected only up to 0.5kilolambda distance. We recommend using: UVRANGE 0.7,0 for D array UVRANGE 0.7,0 for C array After calibration, if UVPLT still shows signs of solar interference,it means that not enough short baselines were discarded; therefore the calibration has to be redone and UVRANGE to be reset. Note that the Sun might rise or set, especially during a long B-array run, in which case you might wish to split the calibration by timerange in a set affected and a set without solar interference. 14a. Primary (flux density) calibrators --> SN/1 default CALIB calsour '1328+307','' $ flux density calibrator #1 get2n 3C286_L.MODEL.1 nmap 1 ; ncomp 1e6,0 ; inver 1 ; cmethod 'DFT' freqid -1 docal 1 ; gainuse 1 flagver 1 refant 5 $ Change this to your refant solint 0 aparm 4,0,0,0,0,2; $ min 4 antennas; print closures soltype 'L1'; solmode 'A&P'; weightit 1 $ true L1 minimization solcon 0 minamper 10; minphser 10 $ complain if >10%/10d off cparm 0,0,10,10,1 $ complain if avg > 10%/10d off snver 1 getn *.NEWCH0 $ ***NOTE: must run this for all NEWCH0.1,2 in which $ this calibrator appears! --> SN/1 14b. Secondary (phase) calibrator --> SN/1 ***Check uv restrictions for secondary calibrators carefully. For 1313+675: no restrictions, so uvra= 0,0 . default CALIB calsour '1358+624','' $ phase calibrator uvrange 0,0 wtuv 0.0 $ may have to set wtuv 0.01 if solutions are $ crazy and uvrange is not 0,0 freqid -1 docal 1 ; gainuse 1 flagver 1 refant 5 $ Change this to your refant solint 0 aparm 4,0,0,0,0,2; $ min 4 antennas; print closures soltype 'L1'; solmode 'A&P'; weightit 1 $ true L1 minimization solcon 0 minamper 10; minphser 10 $ complain if >10%/10d off cparm 0,0,10,10,1 $ complain if avg > 10%/10d off snver 1 getn *.NEWCH0 $ ***NOTE: must run this for all NEWCH0.1,2,3 in which $ this calibrator appears! 15b. GETJY SN/1-3, SU/1 executed on 20 July 2010 ***Find flux density of secondary calibrator, and set SN table amplitude gains to reflect a common flux density scale. default GETJY sources '1358+624','' $ Secondary (phase) calibrators) calsour '1328+307','' $ Primary (flux) calibrators freqid -1 snver 1 $ Use all SN tables getn *.NEWCH0.1 Task GETJY (release of 31DEC08) begins uhppc5> GETJY1: Source:Qual CALCODE IF Flux (Jy) uhppc5> GETJY1: 1358+624 : 5 C 1 4.18672 +/- 0.00429 uhppc5> GETJY1: Appears to have ended successfully 16. SN table checks 16a. SNPLT last SN table executed on 20 July 2010 16a1. SNPLT phase: default SNPLT inext 'sn';inver 0 pixrange 0 opcode 'alsi';do3col 1;dotv 1; nplots 9 factor 2; symbol 5 xinc 1; optype 'phas'; getn *.NEWCH0.1 ===> Note any phase jumps (on the phase calibrator) for future flagging. The EVLA antennas, even after applying VLANT, still show quite a bit of phase drift. This is OK so long as a linear interpolation between the phases looks like it will work. 16a2. SNPLT amplitude: default SNPLT inext 'sn';inver 0 pixrange 0 opcode 'alsi';do3col 1;dotv 1; nplots 9 factor 2; symbol 5 xinc 1; optype 'amp'; getn *.NEWCH0.1 ===> Note whether the amp. is roughly constant for a given antenna/pol'n/IF. ***We have seen a couple cases where the first phase cal scan has a significantly different amplitude gain for the EVLA antennas. The reason is not clear but the raw data do show this effect, so CALIB is doing the right thing. This area warrants further tests, to learn whether we should simply flag the EVLA antennas on the first phase calibrator scan. 16b. LISTR/GAIN print SN table executed on 20 July 2010 default LISTR optype 'gain'; Inext 'sn'; inver 0; freqid -1 dparm 5,0; $ Amp & phase factor 0; docrt 132 outprint '' antennas 0; $ may have to list missing antennas explicitly, to avoid $ column overrun. To list missing antennas, use the form $ANTENNAS -3,2,0 to have antennas 3 and 2 left out. getn *.NEWCH0.1 --> check for phase jumps and other inconsistencies. ***We have seen a couple cases where the first phase cal scan has a significantly different amplitude gain for the EVLA antennas. The reason is not clear but the raw data do show this effect, so CALIB is doing the right thing. This area warrants further tests, to learn whether we should simply flag the EVLA antennas on the first phase calibrator scan. uhppc51 LISTR(31DEC08) 524 20-JUL-2010 14:01:42 Page 1 File = DDO165-C3 .NEWCH0. 1 Vol = 3 Userid = 524 IF = 1 Freq= 1.420497397 GHz Ncor= 2 No. vis= 38870 Polarization = R Subarray = 0 Listing SN table, version 1 SN table has not been applied to a CL table Gain amplitudes, 1000 = 10.000000 Stokes = R IF = 1 Freq = 1.420497397 GHz Time Source -- 1-- 2-- 3-- 4-- 5-- 6-- 7-- 8-- 9--10--11--12--13--14--15--16--17--18--19--20--21--22--23--25--26--27--28 Day # 0 03:12:30 1358+624 408 419 402 447 410 423 411 407 420 411 416 415 425 410 415 439 451 428 402 411 408 432 400 408 412 03:56:30 1358+624 409 414 398 449 408 421 404 401 415 407 411 413 431 402 413 430 444 427 402 414 412 435 403 409 420 410 08:24:45 1358+624 393 398 410 376 430 388 404 395 391 397 394 402 395 413 392 396 415 432 409 388 393 389 417 385 389 403 396 09:05:00 1358+624 393 397 411 376 429 387 404 391 389 395 391 400 395 414 390 394 414 432 408 388 395 388 415 386 388 400 395 09:32:00 1328+307 399 403 414 380 437 393 409 397 394 401 398 404 399 418 399 399 419 436 413 394 399 393 424 390 392 409 400 11:01:30 1358+624 393 397 409 376 431 387 403 388 389 394 392 400 393 415 393 392 412 432 409 383 394 387 417 386 386 403 394 11:41:30 1358+624 394 398 410 375 430 389 402 389 386 393 393 398 394 411 396 394 411 432 409 383 390 387 418 386 387 402 396 Type Q to stop, just hit RETURN to continue uhppc51 LISTR(31DEC08) 524 20-JUL-2010 14:01:49 Page 2 File = DDO165-C3 .NEWCH0. 1 Vol = 3 Userid = 524 IF = 1 Freq= 1.420497397 GHz Ncor= 2 No. vis= 38870 Polarization = L Subarray = 0 Listing SN table, version 1 SN table has not been applied to a CL table Gain amplitudes, 1000 = 10.000000 Stokes = L IF = 1 Freq = 1.420497397 GHz Time Source -- 1-- 2-- 3-- 4-- 5-- 6-- 7-- 8-- 9--10--11--12--13--14--15--16--17--18--19--20--21--22--23--25--26--27--28 Day # 0 03:12:30 1358+624 403 428 433 453 418 418 398 427 410 415 384 418 398 407 416 427 445 428 412 408 416 436 409 412 436 03:56:30 1358+624 399 424 429 451 415 416 395 424 404 416 384 414 395 402 414 427 443 426 407 406 416 434 406 412 429 434 08:24:45 1358+624 386 408 405 410 433 396 399 384 414 387 400 369 400 381 390 398 407 430 408 388 385 397 420 392 390 410 421 09:05:00 1358+624 380 407 405 413 431 395 399 382 415 390 396 367 399 384 389 396 408 429 409 387 385 396 422 393 389 408 418 09:32:00 1328+307 389 414 408 417 439 402 402 387 420 394 402 372 406 388 395 402 411 434 413 394 391 402 427 398 395 417 425 11:01:30 1358+624 382 408 405 414 435 397 395 381 414 385 398 368 401 383 388 396 405 427 407 386 383 395 424 395 390 411 418 11:41:30 1358+624 384 408 405 413 433 398 395 380 412 387 398 367 403 382 390 397 404 429 407 388 382 397 424 392 389 411 420 Type Q to stop, just hit RETURN to continue uhppc51 LISTR(31DEC08) 524 20-JUL-2010 14:03:09 Page 3 File = DDO165-C3 .NEWCH0. 1 Vol = 3 Userid = 524 IF = 1 Freq= 1.420497397 GHz Ncor= 2 No. vis= 38870 Polarization = R Subarray = 0 Listing SN table, version 1 SN table has not been applied to a CL table Gain phases in degrees Stokes = R IF = 1 Freq = 1.420497397 GHz Time Source -- 1-- 2-- 3-- 4-- 5-- 6-- 7-- 8-- 9--10--11--12--13--14--15--16--17--18--19--20--21--22--23--25--26--27--28 Day # 0 03:12:30 1358+624 24 22 -92 0 133 -48 119 -30 -83 -63 -94 105 110 -18 -23 114 154 134 122 56 -91 -71 95 171 -139 03:56:30 1358+624 15 20 -93 0 124 -43 109 -32 -91 -70-104 101 111 -31 -20 111 152 132 113 54 -86 -71 98 169-157-143 08:24:45 1358+624 21 30-136 -94 0 126 -26 105 -22-108 -68 -94 101 124 -36 -24 118 152 144 132 61 -66 -64 97 173-165-134 09:05:00 1358+624 26 30-136 -92 0 128 -31 107 -20-108 -64 -88 103 123 -33 -27 119 152 146 137 61 -71 -64 94 175-159-133 09:32:00 1328+307 27 52-130 -85 0 135 -25 110 -15-118 -64 -87 109 129 -31 -13 128 156 153 136 72 -59 -55 91-178-147-130 11:01:30 1358+624 23 30-137 -91 0 134 -28 110 -19-120 -64 -90 109 127 -28 -25 119 150 146 135 63 -69 -61 95 177-158-134 11:41:30 1358+624 22 30-138 -91 0 133 -32 105 -19-122 -67 -88 108 126 -30 -24 120 152 146 135 63 -73 -61 95 177-165-135 Type Q to stop, just hit RETURN to continue uhppc51 LISTR(31DEC08) 524 20-JUL-2010 14:04:23 Page 4 File = DDO165-C3 .NEWCH0. 1 Vol = 3 Userid = 524 IF = 1 Freq= 1.420497397 GHz Ncor= 2 No. vis= 38870 Polarization = L Subarray = 0 Listing SN table, version 1 SN table has not been applied to a CL table Gain phases in degrees Stokes = L IF = 1 Freq = 1.420497397 GHz Time Source -- 1-- 2-- 3-- 4-- 5-- 6-- 7-- 8-- 9--10--11--12--13--14--15--16--17--18--19--20--21--22--23--25--26--27--28 Day # 0 03:12:30 1358+624 -42 61 -142 0 119 48 35-100 93-109 50 15 153 -99 -62-111 -73 -58 90 100 6 8 130-105 117 03:56:30 1358+624 -57 59 -143 0 109 53 24-102 85-114 39 9 153-112 -60-114 -74 -61 80 97 9 6 133-108 -93 114 08:24:45 1358+624 -48 71 150-146 0 105 71 18 -94 69-116 48 8 166-121 -64-107 -76 -49 105 103 30 7 137-105-102 126 09:05:00 1358+624 -44 72 151-145 0 106 65 19 -93 68-114 56 8 165-119 -68-106 -76 -49 110 103 25 6 134-103 -97 127 09:32:00 1328+307 -43 93 158-138 0 114 71 22 -88 59-113 59 14 171-115 -54 -97 -71 -42 110 113 37 15 133 -96 -86 131 11:01:30 1358+624 -47 73 152-143 0 113 68 24 -91 56-116 57 14 168-112 -65-105 -77 -49 108 105 27 9 136-101 -96 128 11:41:30 1358+624 -49 72 150-144 0 112 63 19 -92 55-119 60 13 167-115 -65-105 -76 -49 107 104 23 11 136-101-104 126 AIPS 1: Resumes 17. UVFLG -> NEWCH0.1 FG/1 executed on DDmonYY ***If the SN table shows a phase jump on the phase calibrator, you should flag the data between the two phase cal scans which show the jump (since those cannot be calibrated). ***Note that we flag NEWCH0.1, *regardless* of whether the galaxy appears in this data set. This is because later on (step 20/TVFLG) we flag the NEWCH0 data in order from inseq 1 through inseq freqid_max, copying the FG table from one file to the next. UVFLG itself doesn't care whether the flags you enter actually do anything -- it just adds entries to the FG table, which are then applied (or ignored if irrelevant) by other tasks. ***This step may of course be skipped if there are no obvious phase jumps. This example deals with a phase jump on antenna 18. default UVFLG antenna 18,0 $ the antenna which "jumped" timer 0 6 33 0 0 6 59 0; $ the source scan between the offending ph.cal scans opcode 'FLAG' reason 'phase jump' outfgver 1 getn *.NEWCH0.1 --> NEWCH0.1 FG/1 NOT NEEDED! 18. CLCAL NEWCH0 --> CL/3 executed on 20 July 2010 ***For multi-FREQID data this becomes rather complicated, since we need a new CL table for every NEWCH0 file, to allow detailed checks and second-order flagging. ***Note that there is no need to work around any phase jumps, since the intervening data are flagged (see step 17 above [UVFLG]). 18a. CLCAL for the primary calibrators -> CL/3 default CLCAL sour= '1328+307','' $ Primary (flux) calibrators calsour= sour interpol 'SELF' gainver 1 ; gainuse 2 refant 5 $ Change this to your refant dobtween -1 $ Don't interpolate entries for different sources snver 1 $ if multiple FREQIDs getn *.NEWCH0.1 $ do this for all NEWCH0 with primary (flux) $ calibrator data 18b. CLCAL for the phase calibrator and galaxy -> CL/3 default CLCAL sour= '1358+624','U08201','' $ Secondary (phase) calibrator + galaxy calsour= '1358+624','' $ Secondary (phase) calibrator interpol 'SIMP' gainver 1 ; gainuse 2 refant 5 $ Change this to your refant dobtween -1 $ Don't interpolate entries for different sources cutoff 120 $ Don't extrapolate/interpolate beyond 120 minutes snver 1 $ if multiple FREQIDs ***If your data set used +/- frequency switching for the phase calibrator (our observations did not, but some archival data may), you should use BPARM with SAMPTYPE='BOX' to select a smoothing time which covers both frequency settings. LISTR/SCAN on LINCOP will help you choose this; normally something like 12 minutes should be OK. getn *.NEWCH0.1 $ do this for all NEWCH0 with secondary (phase) $ calibrator or galaxy data ***At this point we have a new CL table for all NEWCH0 files. 19a. ANBPL executed on 20 July 2010 ***We use ANBPL to check the data weights. Data with very high weights (factor 5-10 or more above normal) should be flagged with UVFLG. default ANBPL docalib 1;gainuse 2 flagver 1 bparm 2,17,0 $ Plot antenna-based weight vs. time nplots 9; dotv 1 docrt 132 $ Print as well as plotting weights -- useful for $ finding exact times of bad weights $ Note you can also use outprint to send to a file. opcode 'alsi' $ Plot all IFs together do3col 1 $ ...using different colors getn *.NEWCH0.1 $ Must do this separately for every NEWCH0 file 19b. UVFLG to eliminate very high weights ***Should UVFLG on NEWCH0.1, even if Evil Weights are seen in NEWCH0.2 or NEWCH0.3 -- we'll be copying FG/1 from NEWCH0.1 to NEWCH0.2 for subsequent second-order flagging. 20. TVFLG FG/1 executed on 20 July 2010 20a. TVFLG on calibrators: NEWCH0.1 The calibrators should now have constant amplitude and zero phase...apart from source structure for the primary (flux) calibrators, and any uvrange for the secondary (phase) calibrators. If we see huge problems on the calibrators we may have to re-run CALIB etc. -- let's hope not!! default TVFLG calcode '*' $ calibrators only docat -1 $ avoid saving temporary files dohist -1 $ avoid creation of history entries docalib 1 ; gainuse 2 $ apply the new CL table flagver 1;outfgver 1 $ keep all flags in FG/1 dparm 0 dparm(3) 1 $ show baselines twice, to treat all antennas identically -- $ this displays baseline 27-1 as well as 1-27 dparm(6)=30 $ time resolution: should be set to the calibrators' $ integration time, in seconds getn *.NEWCH0.1 ***Within TVFLG: - Set useful defaults: SMOOTH=1 to avoid averaging date before displays SCAN= 20 to use a long time for median filters (AMP/PH DIFF) FLAG ALL CHANNELS FLAG STOKES FULL (usually -- sometimes you'll want NORR or NOLL) ***If individual Stokes need to be flagged, make sure you set the STOKES FLAG to correspond to the polarization that is displayed on the TV SWITCH SOURCE FLAG to ONE-SOURCE to avoid inadvertantly flagging your galaxy (though sometimes you'll want to of course) - Be sure to inspect BOTH polarizations! ***We suggest the following steps: - Set the above defaults - Check AMPLITUDE, AMP DIFF, PHS DIFF. Be wary of known source structure and uv-range limits!! ***Note: occasionally, flagging using UVFLG can be more straightforward (e.g., deleting an antenna). 21. Calibration/flagging checks: calibrators 21a. UVPLT executed on 20 July 2010 ***Check the amp & phase vs. uv-distance for all calibrators. Amplitude should match the results of SETJY/GETJY. If there are obvious outliers which are not expected due to source structure, go back and flag those (and possibly re-run CALIB etc.). default UVPLT calco '*' docal 1 ; gainuse 2 flagver 1 $ set this to the latest FG version -- may be >1 if $ there are multiple NEWCH0s (FREQIDs). dotv 1 do3col 1 getn *.NEWCH0.1 $ do this for each NEWCH0 file bparm 0 $ amp. vs. uv-distance bparm 0,2 $ phase vs. uv-distance The primary calibrator looks unusual in the phase vs uv-distance plot. 21b. IMAGR executed on DDmonYY [if desired -- this is not really necessary] default IMAGR sources '0702+445','' $ calibrator to image docalib 1; gainuse 3 $ apply latest calibration flagver 1 $ apply latest flags -- set this to the $ highest-numbered FG table outname 'junkcal' $ some obviously cruddy name cellsize 1 $ for B configuration cellsize 3.5 $ for C configuration cellsize 10 $ for D configuration imsize 1024 $for B array imsize 512 $for C and D array niter 1000 nbox 1 ; clbox -1,5,512,513 $ calibrator should be in the center minpa 121 uvwtfn 'NA'; robust 0.5 dotv 1 getn *.NEWCH0.xx $ whichever file has the calibrator you're imaging --> shouldn't see obvious calibration errors or striping. CLEANed flux density should roughly match SETJY/GETJY. Note: If uvwtfn is set to 'NA' it will override any value given to robust. NOT DONE!!! 22. TVFLG on the galaxy: NEWCH0.xx ***This is our first run of flagging on the galaxy. - Check the first scan carefully -- often the system isn't "organized" on this first scan - On-line flagging isn't as reliable as in the old days, so there are plenty of hot pixels and hiccups. - We are NOT quacking, because (1) FILLM's NX table isn't correct; (2) QUACK flags data from the beginning-of-scan, whereas we want to flag data from antennas-on-source. 22b. If there's more than one NEWCH0 (FREQID): ***I assume here that the galaxy is in NEWCH0.3 . If not, you should first TACOP FG/2 from NEWCH0.3 to the file with the galaxy in it. This will now be FG/3 . default TVFLG calcode '-CAL' $ non-calibrators only docat -1 $ avoid saving temporary files dohist -1 $ avoid creation of history entries docalib 1 ; gainuse 2 $ apply the new CL table flagver 1;outfgver 1 $ or flagver 3 ; outfgver 3 if you had to TACOP $ the FG table from another file dparm 0 dparm(3) 1 $ show baselines twice, to treat all antennas identically -- $ this displays baseline 27-1 as well as 1-27 dparm(6)=60 $ time resolution: should be set to the sources' $ integration time, in seconds getn *.NEWCH0.xx $ This should be the file with the galaxy data ***Within TVFLG: - Set useful defaults: SMOOTH=1 to avoid averaging date before displays SCAN= 20 to use a long time for median filters (AMP/PH DIFF) FLAG ALL CHANNELS FLAG STOKES FULL (usually -- sometimes you'll want NORR or NOLL) ***If individual Stokes need to be flagged, make sure you set the STOKES FLAG to correspond to the polarization that is displayed on the TV SWITCH SOURCE FLAG to ONE-SOURCE to avoid inadvertantly flagging your galaxy (though sometimes you'll want to of course) - Be sure to inspect BOTH polarizations! ***We suggest the following steps: - Set the above defaults - Flag first integration in every scan (manual QUACK) -- this should be the first integration AFTER most antennas are on-source, which is why we can't use the usual QUACK. - Check AMPLITUDE (for missing data), AMP DIFF . PHS DIFF may occasionally be useful, but it's likely to be mostly random, unless you have a strong continuum source near your galaxy. ***Note: occasionally, flagging using UVFLG can be more straightforward (e.g., deleting an antenna). 23. Calibration/flagging checks: sources 23a. UVPLT executed on 20 July 2010 ***Check the amp vs. uv-distance for the galaxy. If there are obvious outliers which are not expected due to source structure or RFI (i.e., not mostly on short spacings), go back and flag those. Note any obvious short-spacing horrors, which may be due to solar or terrestrial RFI. default UVPLT docal 1 ; gainuse 2 flagver 1 $ set this to the latest FG version -- may be >1 if $ there are multiple NEWCH0s (FREQIDs). dotv 1 do3col 1 source 'U08201','' getn *.NEWCH0.3 $ whichever file holds the galaxy bparm 0 $ amp. vs. uv-distance 23b. IMAGR executed on 20 July 2010 default IMAGR sources 'U08201','' $ the galaxy docalib 1; gainuse 2 $ apply latest calibration flagver 1 $ apply latest flags -- set this to the $ highest-numbered FG table outname 'junk' $ some obviously cruddy name cellsize 3.5 $ for C configuration imsize 512 $ for C and D configurations niter 1000 nbox 0 minpa 121 uvwtfn 'na'; robust 0.5 dotv -1 getn *.NEWCH0.3 $ whichever file has the source you're imaging --> shouldn't see obvious calibration errors or striping. Note that this "channel 0" includes HI emission, so you may see some odd effects (e.g., very woofly noise in B configuration) -- don't panic! Note: If uvwtfn is set to 'NA' it will override any value given to robust. ### If you find a strong continuum source rippling your map even in a 512x512 imsize D array configuration channel zero image than refer to Elias and Dana for further steps. 24. TASAV -> CH0SAV.1,2,3 executed on 20 July 2010 default TASAV outna 'D165-3MidTaC outcla 'ch0sav' outdi 2 $ Ideally set this to a different disk from indisk, $ in case of disk crashes getn *.NEWCH0 $ loop over NEWCH0 files (= FREQIDs) outse inseq 25. TABED SN, FG tables to LINCOP executed on 20 July 2010 ***Use TABED to ensure FREQID=-1 for all tables (paranoia is your friend...) 25a. NEWCH0.xx FG/yy -> LINCOP FG/2 default TABED opty 'repl' inext 'fg' aparm 0 aparm(1) 3 $ Changing column 3 = FREQID keyval= -1,0 $ ...which we change to FREQID= -1 inver 1 $ if multiple FREQIDs: set this to max. flag table number outver 2 getn *.NEWCH0.3 $ if multiple FREQIDs: set this to file you flagged $ on most recently (usually the file with the $ galaxy in it) getona *.LINCOP --> LINCOP FG/2 25b. NEWCH0.xx SN/yy -> LINCOP SN/1 default TABED opty 'repl' inext 'sn' inver 1 $ if multiple FREQIDs outver 0 aparm 0 aparm(1) 6 $ Changing column 3 = FREQID keyval= -1,0 $ ...which we change to FREQID= -1 getn *.NEWCH0 $ if multiple FREQIDs: all should have same merged SN $ table so you can use whichever NEWCH0 file you want getona *.LINCOP --> LINCOP SN/1 26. CLCAL LINCOP SN/1 --> CL/3 executed on 20 July 2010 ***We do CLCAL directly on LINCOP rather than copying, to avoid (even more) confusion in the multiple-FREQID case. ***Note that there is no need to work around any phase jumps, since the intervening data are flagged (see step 17 above [UVFLG]). 26a. CLCAL for the primary calibrators -> CL/3 default CLCAL sour= '1328+307','' $ Primary (flux) calibrators calsour= sour interpol 'SELF' gainver 1 ; gainuse 2 refant 5 $ Change this to your refant dobtween -1 $ Don't interpolate entries for different sources snver 1 freqid= 1 $ You must run CLCAL once for each FREQID with $ the relevant calibators present getn *.LINCOP 26b. CLCAL for the phase calibrator and galaxy -> CL/3 default CLCAL sour= '1358+624','U08201','' $ Secondary (phase) calibrator + galaxy calsour= '1358+624','' $ Secondary (phase) calibrator interpol 'SIMP' gainver 1 ; gainuse 2 refant 5 $ Change this to your refant dobtween -1 $ Don't interpolate entries for different sources cutoff 120 $ Don't extrapolate/interpolate beyond 120 minutes snver 1 ***If your data set used +/- frequency switching for the phase calibrator (our observations did not, but some archival data may), you should use BPARM with SAMPTYPE='BOX' to select a smoothing time which covers both frequency settings. LISTR/SCAN on LINCOP will help you choose this; normally something like 12 minutes should be OK. freqid= -1 $ You must run CLCAL once for each FREQID with $ the phase calibrator or galaxy present getn *.LINCOP 27. Calibration/flagging checks: calibrators 27a. WIPER executed on 20 July 2010 ***Check the amp & phase vs. uv-distance for all calibrators. Amplitude should match the results of SETJY/GETJY, and phase should be zero, apart from known structure (reflected in source model for gain calibrators and uvrange for phase calibrators). If there are obvious, unexpected outliers, go back and flag those (and possibly re-run various tasks...). default WIPER calcode '*' docal 1 ; gainuse 2 doband 1; bpver 1 $ for multiple-FREQID data sets freqid 1 $ set this to match the calibrator flagver 2 $ should be the latest FG table smooth 7, 117 $ boxcar average over all channels -- use $ smooth 7, 235 if you started with 255 channels dotv 1 do3col 1 bparm 0 getn *.LINCOP bparm(2) 1 $ amp. vs. uv-distance bparm(2) 2 $ phase vs. uv-distance ###It shows a plot similar to the UVPLT output just quicker.It is also useful for identifying which antennas or baselines have calibration problems. 27b. POSSM executed on 20 July 2010 ***Check vector average of all data for each calibrator. Amplitude should match the results of SETJY/GETJY; phase should be flat, and consistent with zero (corresponding to a point source at the origin)...apart from known source structure and possibly HI absorption. default POSSM calcode '*' docal 1 ; gainuse 2 doband 1; bpver 1 $ for multiple-FREQID data sets freqid 1 $ set this to match the calibrator flagver 2 $ should be the latest FG table aparm 0 $ Plot data solint 0 $ average all time nplots 0 $ average all baselines aparm 0 aparm(1) 1 $ vector average source='1358+624','' $ Secondary (phase) calibrator uvrange= 0,0 $ should be set to eliminate known source structure, $ as in CALIB dotv 1 getn *.LINCOP tvinit 27c. IMAGR executed on DDmonYY [if desired -- this is not really necessary] default IMAGR docal 1 ; gainuse 3 doband 1; bpver 1 $ for single-FREQID data sets doband 3; bpver 4 $ for multiple-FREQID data sets freqid 1 $ set this to match the calibrator flagver 2 $ should be the latest FG table outname 'junk' $ some obviously cruddy name cellsize 1 $ for B configuration cellsize 3.5 $ for C configuration cellsize 10 $ for D configuration imsize 1024 $ for B array imsize 512 $ for C and D array niter 200 $ reasonable for a point source nbox 1 ; clbox -1,5,512,513 $ calibrator should be in the center minpa 121 uvwtfn 'na'; robust 0.5 dotv -1 $ so you can go eat lunch getn *.LINCOP ***You shouldn't see obvious calibration errors or striping. CLEANed flux density should roughly match SETJY/GETJY. If you _do_ have Evil Stuff, UVLSF will likely take care of it, so don't get too worked up. Note: If uvwtfn is set to 'NA' it will override any value given to robust. NOT DONE!!! 28. Calibration/flagging checks: sources 28a.1 WIPER executed on 20 July 2010 ***Check the amp vs. uv-distance for the galaxy. If there are obvious outliers which are not expected due to source structure or RFI (i.e., not mostly on short spacings), go back and flag those. Note any obvious short-spacing horrors, which may be due to solar or terrestrial RFI. default WIPER docal 1 ; gainuse 2 doband 1; bpver 1 $ for multiple-FREQID data sets freqid 1 $ set this to match the galaxy flagver 2 $ should be the latest FG table smooth 0 $do not smooth: smoothing will decrease your noise and $consequently show you a lower flux level than the level $that your data has in fact dotv 1 do3col 1 sources 'U08201','' bparm 0 getn *.LINCOP bparm(2) 1 $ amp. vs. uv-distance bparm(2) 2 $ phase vs. uv-distance Use bparm(3)=1;bparm(6)=0;bparm(7)=20 if you want to force a range to the Y axis of the WIPER plot. ###It shows a plot similar to the UVPLT output just quicker.It is also useful for identifying which antennas or baselines have calibration problems.If you do find things you want to flag, UVFLG is highly recommended. #####CAREFUL with smoothing when doing WIPER on the source, it should NOT be done at this step.Smoothing will decrease your noise and consequently show you a lower flux level than the level that your data has in fact. #######It is very probable that when doing a WIPER on all the line data, some channels with junk will ruin your WIPER display and you will not be able to really make out what the clipping level should be. If the junk consists of random hot pixels then just run another WIPER in which you force the y axis to a 0-20 range (bparm(3)=1;bparm(6)=0;bparm(7)=20). If the junk comes in a structured manner than further investigations are needed to identify which baselines, in which channels might be missbehaving. Use WIPER only to identify the problematic baselines and channels, and use TVFLG or UVFLG to remove them form the data. DEFAULT UVFLG opcode 'FLAG' reason 'HOT' anten 9,0 basel 21,0 outfgver 2 getn *.LINCOP DEFAULT UVFLG opcode 'FLAG' reason 'HOT' anten 17,0 basel 7,20,15,0 outfgver 2 getn *.LINCOP 28a.2 Up to which level most of the values(leaving aside the very hot pixels) comfortably fit in? 5Jy ###This is the value that you will be using in CLIP when combining your data!!! 28b. IMAGR executed on 20 July 2010 default IMAGR docal 1 ; gainuse 2 doband 1; bpver 1 $ for multiple-FREQID data sets freqid 1 $ set this to match the galaxy flagver 2 $ should be the latest FG table outname 'junk_line' $ some obviously cruddy name cellsize 3.5 $ for C configuration imsize 512 $ for C configuration niter 1000 $ a light clean, just to see what we've got. niter 0 $ would be ok too, esp. if you IMLIN afterwards nbox 0 ; clbox 0 minpa 121 uvwtfn 'NA'; robust 0.5 dotv -1 $ so you can go eat lunch sourc 'U08201','' getn *.LINCOP ***You shouldn't see obvious calibration errors or striping. You should however see of order 100 mJy of continuum sources in the field, as well as some indication of your galaxy. The latter may be quite confusing for B configuration, which resolves out most of the structure. Don't fret until you've combined all the array configurations. Note: If uvwtfn is set to 'NA' it will override any value given to robust. ### If you find a strong continuum source rippling your map even after trying a 512x512 imsize D array configuration cube than refer to Elias and Dana for further steps. 28c. Noise Estimations: calculated on 20 of July 2010 ##The easiest way to calculate the expected sensitivity is to say 7 S(mJy) = ---------------------------- sqrt{ N (N-1) delta_nu t} where 7 is a constant that depends on the system temperature of the receivers(a quite conservative value) N = number of antennas in the array, delta_nu = channel resolution in MHz, and t = integration time in hours. You need to use for N the number of Antennas which have on average been giving good data during the run. The total time should be the actual time spent on source. No need to be super precise, of course. One simply wants to get a ballpark figure which is good to 10-20%. ###Note that for data which are Hanning smoothed (archive data) the channel spacing is equal to the resolution delta_nu. Without Hanning smoothing, the resolution is ~1.4 x delta_nu (note that after offline Hanning smoothing, if you preserve all channels, the resolution becomes 2 x delta_nu; it reverts to a new "double the old delta_nu" if you delete every other channel). ####Finally, if you want to know the noise in a single visibility, use N=2 and t = 1/360, and probably multiply by sqrt{2} because a visibility is a single polarisation as well. N =27; t=90/60; delta_nu=0.0122 The Expected noise level is: 1.95mJy The rms Noise level in a line free channel is: 2.51mJy 29. TASAV -> EndTaB.LINSAV.1 executed on 20th of July 2010 default TASAV outna 'D165-3EndTaC outcla 'linsav' outdi 2 $ Ideally set this to a different disk from indisk, $ in case of disk crashes getn *.LINCOP I AM HERE !!!! 30. FITTP executed on DDmonYY create: DDO210_B_UV_CALIB_NEWCH0.FITS $ one per FREQID DDO210_B_UV_CALIB_LINCOP.FITS DDO210_B-BeginTasav.FITS DDO210_B-MidTasav.FITS $ one per FREQID DDO210_B-EndTasav.FITS 31. Send to DEIDRE DDmonYY See Little THINGS Web site for current instructions. Apart from the FITS data from step 29/FITTP, the following should be archived: * Observing log * This data reduction log * LISTR/SCAN output (if saved to a file) 31. Celebrate your victory with an appropriate beverage! ================================================================================ ================================================================================ Ater the data has been checked by an independent member of the team and changes/corrections have been suggested the log should continue here with the steps that have been reiterated and the values used in the reiteration. If you need to recreate tables it is best at this stage to not delete the already existing ones but rather to give the tables higher version numbers.