This is an old revision of the document!
GLOW Interferometry Tutorial: Wednesday
We will reduce the 3C129 polarization continuum dataset from the 2008 NRAO summer school. (See http://casa.nrao.edu/Tutorial/SIworkshop2008/ ) The summer school used CASA for the data reduction. You are welcome to try to use CASA for the data reduction on your own (but see also the warnings about what to do what CASA crashes frequently), but we will do the basic reduction in AIPS.
2010 Nov 16: JMA updated for 31DEC10 AIPS
Web Image of 3C129
Wide-field 90 cm image of the large head-tail radio galaxy 3C129 (right). The bright source at the left is 3C129.1. From Lane et al., AJ, 123, 2985, 2002.
The 5 GHz observations being reduced here will only look at the central, brightest, portion of this source.
Data Reduction
Remember, the purpose f this exercise is not to teach you how to reduce radio interferometry data with AIPS. Consider all of the arcane incantations below as just that, magic incantations. You should instead try to figure out what each step is actually doing to the data. The AIPS Cookbook has quite a bit of information to help guide you. Check out chapters 4 and 5. (Note that you probably have a copy of the cookbook in your local AIPS installation if you don't have full web access.) However, at some of the most important points, the cookbook is relatively useless for understanding what is going on, as opposed to knowing which buttons to push, so ask your tutorial leader for help in this area.
Download the data from http://casa.nrao.edu/Data/VLA/3C129/3c129data.tgz and untar it in some directory. (If you are in Garching, there should be a local copy. Ask Sven.) Then, from that same directory, start aips. Login with a new user ID number.
Basic Environment
dowait 1
dohist=1
docrt=132
dotv=1
Load the raw data: FILLM
task 'fillm'
default
nfiles 0
prtlev 0
datain 'PWD:AT166_
doconcat true
clron
doweight 10
ncount 2
cparm(4)=28
cparm(8)=10./60
dparm 0
bparm 0
timer 0
vlamode = ' '
band = ' '
calcode ' '
clron
outdisk 1
go
Check where it went. You will need the C band version at 5 GHz
indi 1
pcat
getn 4
imhe
<AIPS 1: Got(1) disk= 1 user= 100 type=UV 19940725.C BAND.2
AIPS 1: Image=MULTI (UV) Filename=19940725 .C BAND. 2
AIPS 1: Telescope=VLA Receiver=VLA
AIPS 1: Observer=AT166 User #= 100
AIPS 1: Observ. date=25-JUL-1994 Map date=16-NOV-2010
AIPS 1: # visibilities 216975 Sort order TB
AIPS 1: Rand axes: UU-L-SIN VV-L-SIN WW-L-SIN BASELINE TIME1
AIPS 1: SOURCE FREQSEL
AIPS 1: ----------------------------------------------------------------
AIPS 1: Type Pixels Coord value at Pixel Coord incr Rotat
AIPS 1: COMPLEX 3 1.0000000E+00 1.00 1.0000000E+00 0.00
AIPS 1: STOKES 4 -1.0000000E+00 1.00 -1.0000000E+00 0.00
AIPS 1: FREQ 1 4.8851000E+09 1.00 5.0000000E+07 0.00
AIPS 1: IF 2 1.0000000E+00 1.00 1.0000000E+00 0.00
AIPS 1: RA 1 00 00 00.000 1.00 3600.000 0.00
AIPS 1: DEC 1 00 00 00.000 1.00 3600.000 0.00
AIPS 1: ----------------------------------------------------------------
AIPS 1: Coordinate equinox 1950.00
AIPS 1: Maximum version number of extension files of type HI is 1
AIPS 1: Maximum version number of extension files of type AN is 1
AIPS 1: Maximum version number of extension files of type NX is 1
AIPS 1: Maximum version number of extension files of type SU is 1
AIPS 1: Maximum version number of extension files of type FQ is 1
AIPS 1: Maximum version number of extension files of type CL is 1
AIPS 1: Maximum version number of extension files of type TY is 1
AIPS 1: Maximum version number of extension files of type OF is 1
AIPS 1: Keyword = 'CORRMODE' value = ' '
AIPS 1: Keyword = 'VLAIFS ' value = 'ABCD '
AIPS 1: Keyword = 'CORRCOEF' value = -1
/file>
==== Print out some useful information ====
''
task 'listr'\\
default\\
getn 4\\
optype 'scan'\\
doweight 1\\
go\\
''
<file>
AIPS 1: Got(1) disk= 1 user= 101 type=UV 19940725.C BAND.2
vlb054 LISTR(31DEC08) 101 13-NOV-2008 15:25:41 Page 1
File = 19940725 .C BAND. 2 Vol = 1 Userid = 101
Freq = 4.885100000 GHz Ncor = 4 No. vis = 216975
Scan summary listing
Scan Source Qual Calcode Sub Timerange FrqID START VIS END VIS
1 2345-167 : 0003 A 1 0/07:41:45 - 0/07:43:25 1 1 2917
2 A2597 : 0003 1 0/08:00:25 - 0/08:02:35 1 2918 6788
3 2345-167 : 0003 A 1 0/08:21:05 - 0/08:22:45 1 6789 9709
4 A2597 : 0003 1 0/08:39:45 - 0/08:41:55 1 9710 13605
5 2345-167 : 0003 A 1 0/09:00:25 - 0/09:02:05 1 13606 16505
6 A2597 : 0003 1 0/09:19:05 - 0/09:21:15 1 16506 20401
7 2345-167 : 0003 A 1 0/09:39:45 - 0/09:41:25 1 20402 23322
8 A2597 : 0003 1 0/09:58:25 - 0/10:00:35 1 23323 27218
9 2345-167 : 0003 A 1 0/10:19:05 - 0/10:20:45 1 27219 30140
10 A2597 : 0003 1 0/10:37:45 - 0/10:39:55 1 30141 34036
11 2345-167 : 0003 A 1 0/10:58:25 - 0/11:00:05 1 34037 36957
12 A2597 : 0003 1 0/11:17:05 - 0/11:19:15 1 36958 40832
13 2345-167 : 0003 A 1 0/11:37:45 - 0/11:39:25 1 40833 43702
14 0420+417 : 0003 B 1 0/11:48:25 - 0/11:50:05 1 43703 46624
15 3C129 : 0003 1 0/12:12:55 - 0/12:23:05 1 46625 66120
16 0420+417 : 0003 B 1 0/12:27:25 - 0/12:29:05 1 66121 69041
17 3C129 : 0003 1 0/12:50:05 - 0/12:56:05 1 69042 80412
18 3C129 : 0003 1 0/12:56:25 - 0/13:00:15 1 80413 88498
19 0420+417 : 0003 B 1 0/13:04:35 - 0/13:06:15 1 88499 91419
20 3C129 : 0003 1 0/13:29:05 - 0/13:39:15 1 91420 109415
21 0420+417 : 0003 B 1 0/13:43:35 - 0/13:45:15 1 109416 112112
22 3C129 : 0003 1 0/14:06:15 - 0/14:16:25 1 112113 130108
23 0420+417 : 0003 B 1 0/14:20:45 - 0/14:22:25 1 130109 132636
24 3C129 : 0003 1 0/14:45:15 - 0/14:55:25 1 132637 150081
25 0420+417 : 0003 B 1 0/14:59:45 - 0/15:01:25 1 150082 152778
26 3C129 : 0003 1 0/15:18:25 - 0/15:25:35 1 152779 164366
27 0420+417 : 0003 B 1 0/15:30:05 - 0/15:31:45 1 164367 166846
28 3C129 : 0003 1 0/15:55:05 - 0/16:05:15 1 166847 183403
29 0420+417 : 0003 B 1 0/16:10:05 - 0/16:11:45 1 183404 185861
30 3C129 : 0003 1 0/16:34:55 - 0/16:45:05 1 185862 203522
31 0420+417 : 0003 B 1 0/16:49:35 - 0/16:51:15 1 203523 206216
32 0518+165 : 0003 C 1 0/17:06:35 - 0/17:09:45 1 206217 211608
33 0134+329 : 0003 C 1 0/17:21:45 - 0/17:24:55 1 211609 216975
Source summary
Velocity type = ' ' Definition = ' '
ID Source Qual Calcode RA(1950.0) Dec(1950.0) IFlux QFlux UFlux VFlux No. vis
1 2345-167 : 0003 A 23:45:27.6823 -16:47:52.600 0.000 0.000 0.000 0.000 20372
IF( 2) 0.000 0.000 0.000 0.000
2 A2597 : 0003 23:22:43.7000 -12:23:56.000 0.000 0.000 0.000 0.000 23330
IF( 2) 0.000 0.000 0.000 0.000
3 0420+417 : 0003 B 04:20:27.9370 41:43:08.045 0.000 0.000 0.000 0.000 24318
IF( 2) 0.000 0.000 0.000 0.000
4 3C129 : 0003 04:45:31.6950 44:55:19.950 0.000 0.000 0.000 0.000 138196
IF( 2) 0.000 0.000 0.000 0.000
5 0518+165 : 0003 C 05:18:16.5320 16:35:26.900 0.000 0.000 0.000 0.000 5392
IF( 2) 0.000 0.000 0.000 0.000
6 0134+329 : 0003 C 01:34:49.8320 32:54:20.520 0.000 0.000 0.000 0.000 5367
IF( 2) 0.000 0.000 0.000 0.000
ID Source Freq(GHz) Velocity(Km/s) Rest freq (GHz)
1 All Sources 4.8851 0.0000 0.0000
IF( 2) 4.5851 0.0000 0.0000
Frequency Table summary
FQID IF# Freq(GHz) BW(kHz) Ch.Sep(kHz) Sideband
1 1 4.88510000 50000.0039 50000.0039 1
2 4.58510000 50000.0039 50000.0039 1
AIPS 1: Resumes
Where are the antennas located?
go prtan
Location Of VLA Antennas
N36 (26)
N32 ( 1)
N28 (19)
N24 (11)
N20 (15)
N16 (25)
N12 (13)
N8 (27)
N4 (14)
(12) W4 E4 (22)
( 8) W8 E8 ( 4)
( 3) W12 E12 (16)
(28) W16 E16 ( 7)
( 2) W20 E20 (17)
(21) W24 E24 (24)
(10) W28 E28 ( 5)
(18) W32 E32 (23)
(20) W36 E36 ( 6)
VLA:_OUT ( 9)
VPT:_OUT (29)
Flag some bad data. Just run the commands.
task 'uvflg'
default
dohist 1
getn 4
antenna 1,0
basel 0
timer 0 13 45 20 0 15 0 0
stokes ' '
opcode 'flag'
reason 'bad ant'
outfgver 1
go
antenna 14,0
timer 0 16 50 50 0 16 51 0
go
timer 0
Investigate the data
Plots
task 'uvplt'
source '0518+165',' '
calcode ' '
stokes 'half'
timer 0
uvrange 0
bif 0
eif 0
docalib 0
gainuse 1
bparm 0 1
do3col 1
dotv 1
tvinit
go
source '0134+329',' '
tvinit
go
source '0420+417', ' '
tvinit
go
source '3C129', ' '
tvinit
go
bparm 6 7
source '0518+165',' '
tvinit
go
source '0134+329',' '
tvinit
go
source '0420+417', ' '
tvinit
go
source '3C129', ' '
tvinit
go
bparm 11,15,0
sources '0518+165','0134+329','0420+417','3C129',' '
xinc=10
go
bparm 11,16,0
go
xinc=1
bparm 0
Raw visibilities
task 'listr'
optype 'list'
antenna 22,0
basel 0
sources ' '
calcode '*'
bif 0
eif 0
docalib 0
dparm 0
go
Source=0518+165 : 0003, Stokes=RR , IF= 2, Chans= 1- 1 Flux = 0.0000 Jy, Calcode = C , Freq = 4.585100000 GHz Amplitudes, 1000 = 1.000000 Jy, averging type = Vector 0/17:06:55 442 464 454 442 462 497 432 454 471 460 430 418 436 456 456 471 443 453 0/17:07:05 442 463 448 460 456 438 460 441 421 503 435 443 466 452 427 487 415 440 453 455 471 443 452 0/17:07:15 442 459 446 466 454 437 458 439 421 504 440 445 466 451 423 481 415 442 450 459 476 442 458 0/17:07:25 443 462 450 464 455 433 460 445 419 502 435 441 465 452 428 483 417 443 453 456 472 441 453 0/17:07:35 443 464 449 463 455 433 460 442 420 499 435 444 466 451 429 481 420 440 450 457 483 438 456 0/17:07:45 438 459 451 467 453 433 458 440 420 500 432 443 462 453 426 480 415 441 449 456 478 439 454 0/17:07:55 441 461 452 467 453 438 460 438 418 504 438 446 468 456 431 480 415 442 451 458 480 443 453 0/17:08:05 437 460 447 460 454 434 459 445 413 500 439 445 464 454 430 478 419 441 450 458 480 443 453 0/17:08:15 436 459 447 465 459 434 456 443 419 501 440 445 466 452 429 478 416 451 440 450 459 481 440 456 0/17:08:25 438 461 448 464 456 437 460 440 415 504 436 444 465 454 429 475 416 452 442 452 459 476 442 451 Type Q to stop, just hit RETURN to continue vlb054 LISTR(31DEC10) 100 16-NOV-2010 14:51:57 Page 6 Source=0518+165 : 0003, Stokes=RR , IF= 2, Chans= 1- 1 Baselines 01220222032204220522062207220822102211221222132214221522162217221822192220222122222322242225222622272228 0/17:08:35 436 459 445 462 456 434 459 440 418 500 438 438 467 452 431 476 418 455 442 449 462 474 442 455 0/17:08:45 433 455 449 465 455 440 459 439 414 499 435 444 465 453 430 474 414 454 439 447 456 473 441 451 0/17:08:55 437 460 447 462 454 436 458 439 418 499 437 442 466 454 428 480 415 454 441 448 460 472 443 452 0/17:09:05 433 457 448 465 456 436 457 441 416 498 436 445 465 454 433 477 415 451 439 450 459 473 441 456 0/17:09:15 432 464 447 469 454 436 462 441 419 498 438 445 465 453 431 476 417 455 441 452 464 473 444 456 0/17:09:25 428 457 449 468 457 436 459 440 418 493 438 438 462 455 428 470 420 455 441 445 462 469 442 453 0/17:09:35 431 456 446 464 455 434 459 442 414 498 435 441 460 449 426 473 414 449 437 450 458 474 442 454 0/17:09:45 429 458 445 463 451 434 456 442 415 492 437 445 465 450 429 471 419 452 437 449 459 466 439 457 Source=0134+329 : 0003, Stokes=RR , IF= 2, Chans= 1- 1 Flux = 0.0000 Jy, Calcode = C , Freq = 4.585100000 GHz Amplitudes, 1000 = 1.000000 Jy, averging type = Vector Baselines 01220222032204220522062207220822102211221222132214221522162217221822192220222122222322242225222622272228 0/17:22:05 629 683 677 671 687 719 653 704 677 647 685 695 663 676 661 672 643 658 0/17:22:15 630 683 673 666 690 669 685 655 630 723 662 653 692 670 646 694 643 689 666 672 664 681 643 659 0/17:22:25 635 687 671 677 690 671 685 652 631 732 662 651 693 670 646 697 641 694 671 674 664 674 643 660 0/17:22:35 632 683 669 671 692 669 687 651 632 727 663 651 689 667 642 694 639 692 669 667 662 678 640 657 0/17:22:45 629 680 675 668 689 672 687 657 639 730 662 653 691 670 645 694 643 693 671 670 664 679 639 657 0/17:22:55 627 684 670 672 695 669 684 652 629 729 658 651 690 669 644 692 638 684 669 672 664 679 640 656 0/17:23:05 632 685 673 680 695 669 686 649 640 728 658 653 694 676 646 698 643 689 671 672 668 681 635 659 0/17:23:15 635 683 670 673 694 675 689 651 637 728 662 652 695 675 643 696 642 695 667 675 663 682 640 656 0/17:23:25 635 679 672 676 696 667 687 657 631 724 658 648 693 670 649 699 641 694 671 674 662 677 637 664 0/17:23:35 634 684 668 673 690 662 682 653 634 726 659 648 691 670 640 692 639 692 668 669 662 677 639 656 0/17:23:45 628 685 668 678 684 666 684 651 638 732 660 650 690 672 643 695 647 693 676 671 664 678 640 660 0/17:23:55 629 680 672 674 690 671 682 650 637 729 664 655 692 674 643 696 646 692 670 676 666 676 646 659 0/17:24:05 632 686 672 679 695 672 680 654 639 727 663 656 689 675 647 694 647 692 669 670 665 678 641 658 0/17:24:15 630 686 672 674 693 671 689 658 636 728 659 653 691 676 649 698 643 690 669 674 661 684 643 656 0/17:24:25 630 685 674 680 690 676 683 657 637 729 658 652 688 679 645 699 642 697 674 675 666 682 641 659 0/17:24:35 637 681 673 678 693 670 687 658 634 732 659 655 689 678 644 696 644 691 672 675 668 680 642 658 0/17:24:45 632 686 670 677 692 670 685 655 634 722 661 653 689 671 646 698 645 691 669 671 662 677 642 660 0/17:24:55 634 685 675 678 697 675 682 657 632 727 658 654 691 671 643 699 643 693 669 673 666 677 641 658 AIPS 1: Resumes
dparm 1,0
go
Source=0518+165 : 0003, Stokes=RR , IF= 2, Chans= 1- 1 Flux = 0.0000 Jy, Calcode = C , Freq = 4.585100000 GHz Phase, 1000 = 1000.00000 degrees, averging type = Vector 0/17:06:55 105 80-114 -18-170 123 -164 -93 79 57 45 107 -113-174-124 29 -85 -25 0/17:07:05 106 81-112 -76 142 -16-169 98 12 124 -162 -93 80 57 46 -84 109 -113-175-125 28 -87 -25 0/17:07:15 103 78-112 -79 140 -18-169 97 10 121 -164 -95 78 55 43 -86 108 -110-175-124 30 -87 -24 0/17:07:25 104 78-111 -78 141 -17-168 99 9 120 -164 -95 78 55 43 -85 107 -112-176-124 30 -90 -23 0/17:07:35 102 77-112 -78 139 -19-169 98 9 121 -164-100 76 54 42 -88 106 -109-174-122 31 -86 -21 0/17:07:45 102 77-113 -79 138 -19-169 98 9 120 -163-100 75 54 42 -89 106 -109-174-121 31 -86 -21 0/17:07:55 100 74-116 -77 137 -21-171 97 8 118 -165-100 73 53 41 -89 106 -109-173-119 31 -86 -19 0/17:08:05 101 76-114 -77 138 -19-171 99 9 122 -163 -98 74 54 43 -88 108 -110-173-120 29 -86 -20 0/17:08:15 100 78-115 -76 139 -18-171 99 10 121 -163 -98 76 55 44 -89 110 -85-110-174-119 28 -86 -20 0/17:08:25 101 79-115 -75 139 -19-167 101 10 120 -163 -98 75 55 45 -88 109 -83-111-175-121 28 -88 -21 Type Q to stop, just hit RETURN to continue vlb054 LISTR(31DEC10) 100 16-NOV-2010 14:54:07 Page 6 Source=0518+165 : 0003, Stokes=RR , IF= 2, Chans= 1- 1 Baselines 01220222032204220522062207220822102211221222132214221522162217221822192220222122222322242225222622272228 0/17:08:35 103 80-113 -76 141 -17-167 102 13 120 -160 -95 75 55 47 -87 110 -81-113-177-121 27 -87 -22 0/17:08:45 106 80-112 -75 140 -16-168 102 15 122 -159 -94 78 55 50 -87 111 -81-114 176-122 26 -88 -23 0/17:08:55 108 80-110 -76 141 -15-168 106 17 122 -157 -92 79 55 51 -85 111 -79-115 175-123 26 -92 -26 0/17:09:05 105 77-110 -76 140 -17-169 105 16 121 -158 -94 78 53 49 -87 109 -81-113 176-123 28 -90 -23 0/17:09:15 105 78-109 -78 139 -18-168 105 17 123 -159 -98 80 53 48 -88 108 -82-113 177-123 29 -92 -24 0/17:09:25 108 77-108 -77 140 -18-166 107 20 124 -159 -97 81 56 47 -86 109 -81-113 176-123 28 -95 -27 0/17:09:35 112 80-106 -74 141 -16-165 107 23 126 -156 -94 84 57 48 -84 107 -78-114 180-126 24 -96 -31 0/17:09:45 108 81-102 -75 140 -15-165 105 22 125 -156 -93 83 57 46 -85 107 -78-114-179-125 25 -96 -28 Source=0134+329 : 0003, Stokes=RR , IF= 2, Chans= 1- 1 Flux = 0.0000 Jy, Calcode = C , Freq = 4.585100000 GHz Phase, 1000 = 1000.00000 degrees, averging type = Vector Baselines 01220222032204220522062207220822102211221222132214221522162217221822192220222122222322242225222622272228 0/17:22:05 84 88-111 -5-173 107 171 71 41 51 -98 -66-102-153 -91 54 -86 -12 0/17:22:15 85 88-109 -80 148 -2-172 89 42 110 172-102 76 43 55 -96 145 -70-104-154 -93 51 -88 -12 0/17:22:25 84 91-108 -84 146 -7-176 86 41 105 172-102 73 40 53-100 142 -76-103-152 -93 52 -85 -10 0/17:22:35 82 91-110 -85 148 -5-176 85 42 102 175-100 76 41 50-100 143 -80-106-153 -96 50 -84 -10 0/17:22:45 81 90-113 -83 150 -4-176 84 43 103 176 -99 79 42 53-100 144 -81-108-155 -96 50 -82 -13 0/17:22:55 81 90-114 -84 152 -2-177 83 43 98 175-106 75 41 53-101 144 -72-111-155 -95 48 -79 -20 0/17:23:05 79 86-119 -88 151 -3-179 79 39 96 173-109 71 36 50-102 143 -72-110-153 -94 48 -73 -19 0/17:23:15 82 85-116 -88 154 1-177 84 43 99 175-105 73 36 54 -98 145 -77-116-157 -96 46 -74 -26 0/17:23:25 87 90-113 -86 159 4-173 88 45 99 179-101 76 38 60 -94 150 -75-118-161 -99 42 -76 -25 0/17:23:35 90 90-108 -82 161 9-170 89 48 101 -179 -98 78 41 64 -91 152 -73-120-164-101 41 -76 -29 0/17:23:45 86 82-114 -87 154 6-175 84 42 97 175-103 71 37 60 -93 146 -76-114-161 -99 45 -71 -26 0/17:23:55 92 81-115 -86 152 5-174 85 40 98 175-102 71 39 62 -92 148 -77-116-162-102 43 -72 -27 0/17:24:05 99 82-114 -85 152 5-173 87 42 99 177 -98 71 39 66 -90 150 -76-118-164-102 41 -74 -26 0/17:24:15 96 80-114 -81 155 7-172 88 44 103 -179 -98 72 41 69 -89 154 -73-121-167-107 37 -75 -27 0/17:24:25 95 78-119 -79 153 4-175 84 39 97 180 -99 69 40 67 -91 153 -76-119-165-105 37 -69 -25 0/17:24:35 96 79-120 -79 153 5-177 85 41 96 -180 -98 68 42 68 -91 152 -75-118-165-104 35 -68 -20 0/17:24:45 98 75-117 -80 152 5 179 86 38 100 178 -97 68 43 68 -90 149 -74-118-163-105 34 -68 -15 0/17:24:55 99 74-117 -81 151 7 178 88 37 100 176-101 67 45 67 -88 150 -74-117-162-104 33 -69 -12 AIPS 1: Resumes
dparm 0
Start the calibration
Set the flux values of the known calibrators
task 'setjy'
default
getn 4
source '0518+165',' '
bif 0
eif 0
optype 'calc'
aparm(2) 3
go
vlb054> SETJY1: Task SETJY (release of 31DEC10) begins vlb054> SETJY1: **WARNING: OPCODE=CALC AND FREQID = -1 vlb054> SETJY1: FREQID WILL BE RESET TO 1, CHECK YOUR RESULTS CAREFULLY vlb054> SETJY1: A source model for this calibrator is available vlb054> SETJY1: Consult the help file for CALRD for assistance vlb054> SETJY1: / Flux calculated using known spectrum vlb054> SETJY1: BIF = 1 EIF = 2 /Range of IFs vlb054> SETJY1: '0518+165 ' IF = 1 FLUX = 3.7742 (Jy calcd) vlb054> SETJY1: '0518+165 ' IF = 2 FLUX = 3.9464 (Jy calcd) vlb054> SETJY1: / Using (1995.2) VLA or Reynolds (1934-638) coefficients vlb054> SETJY1: Appears to have ended successfully vlb054> SETJY1: vlb054 31DEC10 TST: Cpu= 0.0 Real= 0
bif 1
eif 1
optype ' '
zerosp 3.7742, 0.380, -0.153, 0.0
go
bif 2
eif 2
zerosp 3.9464, 0.397, -0.161, 0.0
go
bif 0
eif 0
zerosp 0
optype 'calc'
source = '0134+329',' '
go
vlb054> SETJY1: Task SETJY (release of 31DEC08) begins vlb054> SETJY1: **WARNING: OPCODE=CALC AND FREQID = -1 vlb054> SETJY1: FREQID WILL BE RESET TO 1, CHECK YOUR RESULTS CAREFULLY vlb054> SETJY1: A source model for this calibrator may be available vlb054> SETJY1: Use the verb CALDIR to see if there is one vlb054> SETJY1: A source model for this calibrator may be available vlb054> SETJY1: Use the verb CALDIR to see if there is one vlb054> SETJY1: / Flux calculated using known spectrum vlb054> SETJY1: BIF = 1 EIF = 2 /Range of IFs vlb054> SETJY1: '0134+329 ' IF = 1 FLUX = 5.4891 (Jy calcd) vlb054> SETJY1: '0134+329 ' IF = 2 FLUX = 5.8249 (Jy calcd) vlb054> SETJY1: / Using (1995.2) VLA or Reynolds (1934-638) coefficients vlb054> SETJY1: Appears to have ended successfully vlb054> SETJY1: vlb054 31DEC08 TST: Cpu= 0.0 Real= 0
Get images (and thus clean components) for the calibrators
task 'calrd'
object '3c138'
band 'c'
go
object '3c48'
band 'c'
go
pcat
AIPS 1: Catalog on disk 1 AIPS 1: Cat Usid Mapname Class Seq Pt Last access Stat AIPS 1: 1 101 19940725 .C BAND. 1 UV 13-NOV-2008 15:24:44 AIPS 1: 2 101 19940725 .X BAND. 1 UV 13-NOV-2008 15:23:05 AIPS 1: 3 101 19940725 .X BAND. 2 UV 13-NOV-2008 16:01:14 AIPS 1: 4 101 19940725 .C BAND. 2 UV 13-NOV-2008 16:06:34 AIPS 1: 5 101 19940725 .U BAND. 1 UV 13-NOV-2008 15:23:05 AIPS 1: 6 101 3C138_C .MODEL . 1 MA 13-NOV-2008 16:09:02 AIPS 1: 7 101 3C48_C .MODEL . 1 MA 13-NOV-2008 16:09:22
Convert them to the coordinate system used for the observations
task 'eposw'
getn 6
eposw
getn 7
eposw
Do the actual calibration. Start with 3C138
task 'calib'
default
getn 4
calsour '0518+165',' '
uvrange 0
antenna 0
refant 22
minamper 10
minphser 10
weightit 1
get2n 6
ncomp 0
solmode 'A&P'
aparm(6) 2
solint 2
solsub 2
cparm(3) 10
cparm(4) 10
go
clrmsg
Calibrate 3C48
calsour '0134+329',' '
get2n 7
go
clrmsg
Calibrate the phase calibrator
clr2n
calsour '0420+417', ' '
solint 0
uvrange 20 0
go
clrmsg
Check the results
task 'snplt'
antenna 0
stokes ' '
inext 'sn'
inver 1
sources ' '
timer 0
optype 'amp'
opcode 'alsi'
do3col 1
dotv 1
nplots 9
tvinit
go
optype 'phas'
go
inver 2
optype 'amp'
go
optype 'phas'
go
inver 3
optype 'amp'
go
optype 'phas'
go
Apply the calibration to the phase calibrator
task 'getjy'
sources '0420+417', ' '
calsour '0518+165','0134+329',' '
calcode ' '
bif 0
eif 0
antenna 0
timer 0
snver 0
go
vlb054> GETJY1: Task GETJY (release of 31DEC08) begins vlb054> GETJY1: Source:Qual CALCODE IF Flux (Jy) vlb054> GETJY1: 0420+417 : 3 B 1 1.46472 +/- 0.00304 vlb054> GETJY1: 2 1.46512 +/- 0.00341 vlb054> GETJY1: Appears to have ended successfully vlb054> GETJY1: vlb054 31DEC08 TST: Cpu= 0.0 Real= 0
Redo the phase calibrator calibration
Now that the flux density of the phase calibrator has been found, redo its calibration (just to make sure there are no remnants of some subtle assumptions about its flux density left in AIPS).
inext 'sn'
inver 3
extdest
inver 0
tget calib
go
clrmsg
Apply the calibration to all sources of interest.
task 'clcal'
sources '0518+165','0134+329','0420+417', '3C129', ' '
calsour '0518+165','0134+329','0420+417', ' '
opcode 'cali'
gainver 1
gainuse 2
refant 22
interp '2pt'
doblank 1
go
Have a look at the calibration
Plots
task 'uvplt'
docalib 1
gainuse 2
source '0420+417', ' '
stokes 'half'
aparm 0
bparm 0 1
doweight 1
uvrange 0
tvinit
go
Start the polarization calibration
Check the parallactic angle change
task 'listr'
sources '0518+165','0134+329','0420+417', ' '
inext 'cl'
inver 2
optype 'gain'
dparm 9,0
go
Make a backup of calibration values, in case we mess up
task 'tasav'
clro
go
Now do the polarization calibration using the phase calibrator
task 'pcal'
calsour '0420+417', ' '
timer 0
antenna 0
uvrange 20,0
bif 0
eif 0
docalib 1
gainuse 2
clr2n
pmodel 0
solint 3
soltype 'appr'
prtlev 1
refant 22
bparm 0
cparm 0
go
clrmsg
vlb054> PCAL 1: Calibration source 1 vlb054> PCAL 1: Q+iU=( -0.01035, 0.03766) +/- ( 0.000106, 0.000106) Jy vlb054> PCAL 1: Pol. inten. = 0.03905 +/- 0.000150 Jy, angle = 52.68 +/- vlb054> 0.078 deg vlb054> PCAL 1: 0420+417 I,Q,U,V = 1.4647 -0.01035 0.03766 0.00000 J vlb054> y vlb054> PCAL 1: Calibration source 1 vlb054> PCAL 1: Q+iU=( -0.03423, 0.00815) +/- ( 0.000114, 0.000114) Jy vlb054> PCAL 1: Pol. inten. = 0.03519 +/- 0.000161 Jy, angle = 83.31 +/- vlb054> 0.093 deg vlb054> PCAL 1: 0420+417 I,Q,U,V = 1.4651 -0.03423 0.00815 0.00000 J vlb054> y
Using the calibration, check the difference between polarizations on a polarized calibrator
task 'rldif'
source '0518+165', ' '
timer 0
antenna 0
uvrange 0,45
docalib 1
gainuse 2
dopol true
go
Ampscalar average of matrix = -30.19( 0.081) sigma = 1.160 Ampscalar average of matrix = 33.93( 0.097) sigma = 1.389
outputs
AIPS 1: RLDIF: Task to return Right - Left phase difference AIPS 1: Adverbs Values Comments AIPS 1: ---------------------------------------------------------------- AIPS 1: CLCORPRM -30.1863 33.9257 R-L phase difference returned AIPS 1: *rest 0
Another save, just in case
task 'tasav'
clro
go
What is the angle supposed to be for this calibrator?
Polarization data for C band from http://www.vla.nrao.edu/astro/calib/polar/1999/
Correct number is -21.71
Correct the measured values
for i=1 to 2;clcorp(i) = -21.71 - clcorp(i);end
Apply them
task 'clcor'
source ' '
antenna 0
timer 0
bif 0
eif 0
gainver 2
gainuse 0
opcode 'polr'
stokes 'l'
go
Check that the angles match what we expect
task 'rldif'
source '0518+165', ' '
timer 0
antenna 0
uvrange 0,45
docalib 1
gainuse 3
dopol true
go
Look at what AIPS gave back
outputs
AIPS 1: RLDIF: Task to return Right - Left phase difference AIPS 1: Adverbs Values Comments AIPS 1: ---------------------------------------------------------------- AIPS 1: CLCORPRM -21.71 -21.71 R-L phase difference returned AIPS 1: *rest 0
###############
Now start with the smaller array data. Load it in
FILLM
task 'fillm'
default
nfiles 2
prtlev 0
datain 'PWD:AT166_
doconcat true
clron
doweight 10
ncount 1
cparm(4)=28
cparm(8)=10./60
go
Check where it went
pcat
AIPS 1: Catalog on disk 1 AIPS 1: Cat Usid Mapname Class Seq Pt Last access Stat AIPS 1: 1 101 19940725 .C BAND. 1 UV 13-NOV-2008 17:24:12 AIPS 1: 2 101 19940725 .X BAND. 1 UV 13-NOV-2008 17:24:13 AIPS 1: 3 101 19940725 .X BAND. 2 UV 13-NOV-2008 17:24:13 AIPS 1: 4 101 19940725 .C BAND. 2 UV 13-NOV-2008 17:24:13 AIPS 1: 5 101 19940725 .U BAND. 1 UV 13-NOV-2008 17:24:13 AIPS 1: 6 101 3C138_C .MODEL . 1 MA 13-NOV-2008 16:16:53 AIPS 1: 7 101 3C48_C .MODEL . 1 MA 13-NOV-2008 16:19:09 AIPS 1: 8 101 19940725 .TASAV . 1 UV 13-NOV-2008 17:24:13 AIPS 1: 9 101 19940725 .TASAV . 2 UV 13-NOV-2008 17:24:13 AIPS 1: 10 101 19941103 .C BAND. 1 UV 13-NOV-2008 17:24:36 AIPS 1: 11 101 19941103 .X BAND. 1 UV 13-NOV-2008 17:24:36 AIPS 1: 12 101 19941103 .X BAND. 2 UV 13-NOV-2008 17:24:36 AIPS 1: 13 101 19941103 .C BAND. 2 UV 13-NOV-2008 17:24:36
Makre sure we have the right one
getn 13
imhe
Get the scan information
task 'listr'
default
getn 13
optype 'scan'
doweight 1
go
vlb054 LISTR(31DEC08) 101 13-NOV-2008 17:25:15 Page 1
File = 19941103 .C BAND. 2 Vol = 1 Userid = 101
Freq = 4.885100000 GHz Ncor = 4 No. vis = 52167
Scan summary listing
Scan Source Qual Calcode Sub Timerange FrqID START VIS END VIS
1 0134+329 : 0003 C 1 0/04:05:15 - 0/04:07:25 1 1 36
2 0420+417 : 0003 B 1 0/07:33:35 - 0/07:35:15 1 37 3169
3 0518+165 : 0003 C 1 0/07:42:35 - 0/07:45:45 1 3170 9457
4 3C129 : 0003 1 0/08:18:05 - 0/08:23:25 1 9458 20308
5 0420+417 : 0003 B 1 0/08:27:35 - 0/08:29:15 1 20309 22845
6 0420+417 : 0003 B 1 0/08:49:25 - 0/08:51:05 1 22846 25972
7 3C129 : 0003 1 0/09:07:05 - 0/09:12:25 1 25973 35132
8 0420+417 : 0003 B 1 0/09:17:05 - 0/09:18:45 1 35133 38213
9 3C129 : 0003 1 0/09:40:25 - 0/09:45:05 1 38214 47664
10 0420+417 : 0003 B 1 0/09:49:35 - 0/09:51:55 1 47665 52167
Source summary
Velocity type = ' ' Definition = ' '
ID Source Qual Calcode RA(1950.0) Dec(1950.0) IFlux QFlux UFlux VFlux No. vis
1 0134+329 : 0003 C 01:34:49.8320 32:54:20.520 0.000 0.000 0.000 0.000 36
IF( 2) 0.000 0.000 0.000 0.000
2 0420+417 : 0003 B 04:20:27.9370 41:43:08.045 0.000 0.000 0.000 0.000 16381
IF( 2) 0.000 0.000 0.000 0.000
3 0518+165 : 0003 C 05:18:16.5320 16:35:26.900 0.000 0.000 0.000 0.000 6288
IF( 2) 0.000 0.000 0.000 0.000
4 3C129 : 0003 04:45:31.6950 44:55:19.950 0.000 0.000 0.000 0.000 29462
IF( 2) 0.000 0.000 0.000 0.000
ID Source Freq(GHz) Velocity(Km/s) Rest freq (GHz)
1 All Sources 4.8851 0.0000 0.0000
IF( 2) 4.5851 0.0000 0.0000
Frequency Table summary
FQID IF# Freq(GHz) BW(kHz) Ch.Sep(kHz) Sideband
1 1 4.88510000 50000.0039 50000.0039 1
2 4.58510000 50000.0039 50000.0039 1
AIPS 1: Resumes
Get antenna positions
go prtan
Location Of VLA Antennas
N18 (26)
N16 ( 1)
N14 ( 9)
N12 (11)
N10 (15)
N8 (27)
N6 (25)
N4 (14)
N2 (13)
( 3) W2 E2 ( 4)
(12) W4 E4 (22)
(21) W6 E6 (16)
( 8) W8 E8 (17)
( 2) W10 E10 (24)
(10) W12 E12 ( 5)
(18) W14 E14 (23)
(28) W16 E16 ( 7)
(20) W18 E18 ( 6)
VLA:_OUT (19)
VPT:_OUT (29)
AIPS 1: Resumes
Flag some bad data. Just run the commands and think about this later.
task 'uvflg'
default
dohist 1
getn 13
antenna 0
basel 0
timer 0 0 0 0 0 4 8 0
stokes ' '
opcode 'flag'
reason 'bad scan'
outfgver 1
go
timer 0 8 18 0 0 8 30 0
go
antenna 0
timer 0 9 10 0 0 9 15 0
go
reason 'bad ant
antenna 4,0
timer 0
Check out some properties of the raw data
Plots
task 'uvplt'
source '0518+165',' '
calcode ' '
stokes 'half'
timer 0
uvrange 0
bif 0
eif 0
docalib 0
gainuse 1
bparm 0 1
do3col 1
dotv 1
tvinit
go
source '0420+417', ' '
tvinit
go
source '3C129', ' '
tvinit
go
bparm 6 7
source '0518+165',' '
tvinit
go
source '0420+417', ' '
tvinit
go
source '3C129', ' '
tvinit
go
bparm 0
Raw numbers
task 'listr'
optype 'list'
antenna 4,0
basel 0
sources ' '
calcode '*'
bif 0
eif 0
docalib 0
stokes ' '
dparm 0
go
Begin the calibration
Apply the flux densities for the known calibrators
task 'setjy'
default
getn 13
source '0518+165',' '
bif 0
eif 0
optype 'calc'
aparm(2) 2
go
vlb054> SETJY1: BIF = 1 EIF = 2 /Range of IFs vlb054> SETJY1: '0518+165 ' IF = 1 FLUX = 3.7742 (Jy calcd) vlb054> SETJY1: '0518+165 ' IF = 2 FLUX = 3.9464 (Jy calcd) vlb054> SETJY1: / Using (1995.2) VLA or Reynolds (1934-638) coefficients
bif 1
eif 1
optype ' '
zerosp 3.7742, 0.380, -0.153, 0.0
go
bif 2
eif 2
zerosp 3.9464, 0.397, -0.161, 0.0
go
bif 0
eif 0
zerosp 0
optype 'calc'
Run the calibration for 3C138
task 'calib'
default
getn 13
calsour '0518+165',' '
uvrange 0
antenna 0
refant 4
minamper 10
minphser 10
weightit 1
get2n 6
ncomp 0
solmode 'A&P'
aparm(6) 2
solint 2
solsub 2
cparm(3) 10
cparm(4) 10
go
clrmsg
Calibrate the phase calibrator
clr2n
calsour '0420+417', ' '
solint 0
uvrange 0
go
clrmsg
Check the results
task 'snplt'
antenna 0
stokes ' '
inext 'sn'
inver 1
sources ' '
timer 0
optype 'amp'
opcode 'alsi'
do3col 1
dotv 1
nplots 9
tvinit
go
optype 'phas'
go
inver 2
optype 'amp'
go
optype 'phas'
go
Use the amplitude calibrator to get the phase calibrator flux density
task 'getjy'
sources '0420+417', ' '
calsour '0518+165',' '
calcode ' '
bif 0
eif 0
antenna 0
timer 0
snver 0
go
vlb054> GETJY1: Task GETJY (release of 31DEC08) begins\\ vlb054> GETJY1: Source:Qual CALCODE IF Flux (Jy) vlb054> GETJY1: 0420+417 : 3 B 1 1.33893 +/- 0.00641 vlb054> GETJY1: 2 1.34714 +/- 0.00525 vlb054> GETJY1: Appears to have ended successfully vlb054> GETJY1: vlb054 31DEC08 TST: Cpu= 0.0 Real= 0
Redo the phase calibrator calibration
Now that we know the flux density of the phase calibrator, run through its calibration again, just to be sure AIPS doesn't have some information left around from calibrating before with an unknown flux density.
inext 'sn'
inver 2
extdest
inver 0
tget calib
go
clrmsg
Apply the calibration to all sources
task 'clcal'
sources '0518+165','0420+417', '3C129', ' '
calsour '0518+165','0420+417', ' '
opcode 'cali'
gainver 1
gainuse 2
refant 4
interp '2pt'
doblank 1
go
Check the results
Plots
task 'uvplt'
docalib 1
gainuse 2
source '0420+417', ' '
stokes 'half'
aparm 0
bparm 0 1
doweight 1
uvrange 0
tvinit
go
Now start the polarization calibration
Check the paralactic angles
task 'listr'
sources '0518+165','0420+417', ' '
inext 'cl'
inver 2
optype 'gain'
dparm 9,0
go
Make a backup of calibration information
task 'tasav'
clro
go
Run the polarization calibration on the phase calibrator
task 'pcal'
calsour '0420+417', ' '
timer 0
antenna 0
uvrange 0
bif 0
eif 0
docalib 1
gainuse 2
clr2n
pmodel 0
solint 3
soltype 'appr'
prtlev 1
refant 4
bparm 0
cparm 0
go
clrmsg
vlb054> PCAL 1: Calibration source 1 vlb054> PCAL 1: Q+iU=( 0.00444, -0.04706) +/- ( 0.000273, 0.000273) Jy vlb054> PCAL 1: Pol. inten. = 0.04727 +/- 0.000386 Jy, angle = -42.30 +/- vlb054> 0.165 deg vlb054> PCAL 1: 0420+417 I,Q,U,V = 1.3389 0.00444 -0.04706 0.00000 J vlb054> y vlb054> PCAL 1: Calibration source 1 vlb054> PCAL 1: Q+iU=( 0.02002, 0.03901) +/- ( 0.000277, 0.000277) Jy vlb054> PCAL 1: Pol. inten. = 0.04385 +/- 0.000392 Jy, angle = 31.42 +/- vlb054> 0.181 deg vlb054> PCAL 1: 0420+417 I,Q,U,V = 1.3471 0.02002 0.03901 0.00000 J vlb054> y
Check the phase difference between polarizations on a polarization calibrator
task 'rldif'
source '0518+165', ' '
timer 0
antenna 0
uvrange 0,45
docalib 1
gainuse 2
dopol true
go
outputs
AIPS 1: RLDIF: Task to return Right - Left phase difference AIPS 1: Adverbs Values Comments AIPS 1: ---------------------------------------------------------------- AIPS 1: CLCORPRM 132.6554 -74.984 R-L phase difference returned AIPS 1: *rest 0
Make backups again
task 'tasav'
clro
go
Find out what the polarization angle on the sky is supposed to be
Polarization data for C band from http://www.vla.nrao.edu/astro/calib/polar/1999/
Correct number is -21.71
Correct the measured values
for i=1 to 2;clcorp(i) = -21.71 - clcorp(i);end
Apply the corrections
task 'clcor'
source ' '
antenna 0
timer 0
bif 0
eif 0
gainver 2
gainuse 0
opcode 'polr'
stokes 'l'
go
Check that the angles are now correct
task 'rldif'
source '0518+165', ' '
timer 0
antenna 0
uvrange 0,45
docalib 1
gainuse 3
dopol true
go
outputs
AIPS 1: RLDIF: Task to return Right - Left phase difference AIPS 1: Adverbs Values Comments AIPS 1: ---------------------------------------------------------------- AIPS 1: CLCORPRM -21.71 -21.71 R-L phase difference returned AIPS 1: *rest 0
##########################
Work on just the target data now
Run SPLIT on the two datasets
task 'split'
getn 4
source '3C129', ' '
timer 0
bif 0
eif 0
docalib 1
gainuse 3
dopol true
stokes ' '
douvcomp false
aparm 0
go
getn 13
go
clrmsg
Check for where the new datafiles are stored
pcat
AIPS 1: Catalog on disk 1 AIPS 1: Cat Usid Mapname Class Seq Pt Last access Stat AIPS 1: 1 101 19940725 .C BAND. 1 UV 13-NOV-2008 17:24:12 AIPS 1: 2 101 19940725 .X BAND. 1 UV 13-NOV-2008 17:24:13 AIPS 1: 3 101 19940725 .X BAND. 2 UV 13-NOV-2008 17:24:13 AIPS 1: 4 101 19940725 .C BAND. 2 UV 13-NOV-2008 18:24:07 AIPS 1: 5 101 19940725 .U BAND. 1 UV 13-NOV-2008 17:24:13 AIPS 1: 6 101 3C138_C .MODEL . 1 MA 13-NOV-2008 17:51:33 AIPS 1: 7 101 3C48_C .MODEL . 1 MA 13-NOV-2008 16:19:09 AIPS 1: 8 101 19940725 .TASAV . 1 UV 13-NOV-2008 17:24:13 AIPS 1: 9 101 19940725 .TASAV . 2 UV 13-NOV-2008 17:24:13 AIPS 1: 10 101 19941103 .C BAND. 1 UV 13-NOV-2008 17:24:36 AIPS 1: 11 101 19941103 .X BAND. 1 UV 13-NOV-2008 17:24:36 AIPS 1: 12 101 19941103 .X BAND. 2 UV 13-NOV-2008 17:24:36 AIPS 1: 13 101 19941103 .C BAND. 2 UV 13-NOV-2008 18:24:18 AIPS 1: 14 101 19941103 .TASAV . 1 UV 13-NOV-2008 17:54:20 AIPS 1: 15 101 19941103 .TASAV . 2 UV 13-NOV-2008 17:56:30 AIPS 1: 16 101 3C129 .SPLIT . 1 UV 13-NOV-2008 18:24:07 AIPS 1: 17 101 3C129 .SPLIT . 2 UV 13-NOV-2008 18:24:18
Combine the two different observations into one big one
task 'dbcon'
getn 16
get2n 17
go
pcat
AIPS 1: 18 101 3C129 .DBCON . 1 UV 13-NOV-2008 18:28:31
Imaging
IMAGR is the standard imaging tool for AIPS
This will start up an imaging/cleaning session. Draw boxes and clean the source structure. Do this for all 4 Stokes parameters. (Unfortunately, IMAGR requires separate runs for the different Stokes parameters.)
task 'imagr'
getn 18
stokes 'i'
dopol 0
cellsize 0.25,0.25
imsize 2048,2048
clr2n
do3dimag 1
docalib 0
uvrange 0
niter 20000
overlap 1
go
clrmsg
stokes 'q'
go
clrmsg
stokes 'u'
go
clrmsg
stokes 'v'
go
clrmsg
Check where the files went
pcat
AIPS 1: 29 101 3C129 .IBM001. 3 MA 13-NOV-2008 19:46:00 AIPS 1: 30 101 3C129 .ICL001. 5 MA 13-NOV-2008 19:46:00 AIPS 1: 31 101 3C129 .QBM001. 1 MA 13-NOV-2008 19:47:30 AIPS 1: 32 101 3C129 .QCL001. 1 MA 13-NOV-2008 19:47:30 AIPS 1: 33 101 3C129 .UBM001. 1 MA 13-NOV-2008 19:49:06 AIPS 1: 34 101 3C129 .UCL001. 1 MA 13-NOV-2008 19:49:06 AIPS 1: 35 101 3C129 .VBM001. 1 MA 13-NOV-2008 19:49:39 AIPS 1: 36 101 3C129 .VCL001. 1 MA 13-NOV-2008 19:49:39
Polarization images
Combine Q and U to get linear polarization
task 'comb'
opcode 'polc'
getn 32
get2n 34
aparm 0
bparm(1) 28E-6
bparm(2) 28E-6
go
Get the linear polarization angle
opcode 'pola'
go
Check where file went
pcat
AIPS 1: 28 101 3C129 .PPOLC . 1 MA 13-NOV-2008 19:59:45 AIPS 1: 37 101 3C129 .PANG . 1 MA 13-NOV-2008 20:00:28
Look at the images
Linear Polarization
getn 28
tvinit
tvlod
tvfiddle
tvstat
AIPS 1: Mean= 1.3417E-05 rms= 2.8180E-05 JY/BEAM over 178694. pixels
Polarization Angle
getn 37
tvinit
tvlod
tvfiddle
I
getn 30
tvinit
tvlod
tvfiddle
tvstat
Clip the data so we only see information where there is good S/N
task 'comb'
getn 37
get2n 28
opcode 'clip'
aparm(1) 100E-6
aparm(10) 100E-6
bparm 0
outclass 'PANGC'
go
task 'comb'
getn 28
get2n 28
opcode 'clip'
aparm(1) 100E-6
aparm(10) 100E-6
bparm 0
outclass 'POLCC'
go
Check where these files went
pcat
AIPS 1: 38 101 3C129 .PANGC . 1 MA 13-NOV-2008 20:31:21 AIPS 1: 39 101 3C129 .POLCC . 1 MA 13-NOV-2008 20:31:21
Look at the polarization angle
getn 38
tvinit
tvlod
tvfiddle
Plotting your data
Plot I contours and P greyscale
task 'kntr'
getn 30
get2n 28
docont 1
dogrey 2
dovect 0
pixrange 0 1E-3
clev 28E-6
levs=-16,-8,8,16,32,64,128,256,512,1024
dowedge true
cbplot 1
dotv 1
blc 950 950
trc 1500 1500
go
Plot I contours and colors for polarization angle
task 'pcntr'
getn 30
get2n 32
get3n 34
docont 1
dogrey 2
dovect 1
pixrange 0 1E-3
clev 28E-6
levs=-16,-8,8,16,32,64,128,256,512,1024
factor 5
pol3col 1
pcut 80E-6
icut 0
dowedge 0
cbplot 1
dotv 1
blc 950 950
trc 1500 1500
go
Final Images
