listobs gives an overall summary of the data: antenna positions w.r.t. the center of the array, baselines, sources observed, frequency setup, and chronology of the observation. An example follows:
% listobs vis=cx012.SS433.2006sep07.1.miriad
Opening File: cx012.SS433.2006sep07.1.miriad
SUMMARY OF OBSERVATIONS
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Input file: cx012.SS433.2006sep07.1.miriad
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Antenna and Baseline Information
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Antenna Locations (in nsec) Antenna Locations (in m)
X Y Z E N U
Antenna 1: -29.9213 -98.3795 41.9036 -29.493 15.429 0.472
Antenna 2: -45.4240 117.2736 60.7055 35.158 22.729 0.188
Antenna 4: -66.6784 21.1092 89.9173 6.328 33.557 0.423
Antenna 5: -87.5850 -149.6982 121.2388 -44.878 44.825 1.123
Antenna 6: -123.4471 -95.6647 168.5641 -28.680 62.626 1.162
Antenna 7: 64.6595 77.8763 -87.9020 23.347 -32.710 -0.538
Antenna 8: 43.7087 42.8510 -59.7407 12.846 -22.188 -0.422
Antenna 9: 35.7017 -64.6192 -48.4809 -19.372 -18.048 -0.287
Antenna 10: 92.9788 -34.3857 -125.6435 -10.309 -46.855 -0.636
Antenna 12: 89.1192 -145.3247 -119.1938 -43.567 -44.615 -0.386
Antenna 13: 17.1266 40.2879 -24.0221 12.078 -8.840 -0.277
Antenna 14: -8.3007 65.6849 9.9469 19.692 3.880 -0.174
Antenna 15: 3.0289 142.9872 -5.0120 42.866 -1.746 -0.188
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Baselines in Wavelengths
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for Decl = 0 deg. Source at Transit
U V W UVdistance
Bsln 1- 2: -19941.18 -1738.59 1433.51 20016.82
Bsln 1- 4: -11048.97 -4439.77 3398.88 11907.61
Bsln 1- 5: 4745.37 -7336.03 5332.09 8737.04
...
Bsln 13-15: -9496.48 -1757.84 1303.60 9657.80
Bsln 14-15: -7148.05 1383.23 -1047.63 7280.65
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Observed Sources Coordinates and Corr Freqs
Source RA Decl Vlsr Corfs in MHz
MARS 12 00 24.86 0 47 14.93 0.00E+00 0.0
3C273 12 29 06.70 2 03 08.60 0.00E+00 0.0
1830+063 18 30 05.94 6 19 16.00 0.00E+00 0.0
SS433 19 11 49.56 4 58 57.60 0.00E+00 0.0
noise 19 11 49.56 4 58 57.60 0.00E+00 0.0
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Frequency Set-up
Source: SS433 UT: 235551 LST: 151057
Line Code: unknown Rest Freq: 92.4688 GHz IF Freq: 0.000 MHz
Velo Code: VELO-LSR Anten Vel: 0.00 km/s First LO: 95.0000 GHz
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Source UT LST Dur Elev Sys Temps (K)
hhmmss hhmmss min deg 1 2 4 5 6 7 8 9 10 12 13 14 15
MARS 232853.5 144355.2 10.0 49. 340 384 295 295 339 490 543 531 339 446 256 352 627
3C273 233938.0 145441.5 10.0 54. 332 376 290 289 331 473 541 520 323 434 247 339 611
1830+063 235255.5 150801.2 2.0 39. 374 432 346 342 394 539 556 591 370 484 292 393 694
SS433 235551.0 151057.1 6.7 30. 437 491 406 394 450 615 689 674 458 581 361 470 776
noise 000242.0 151749.3 0.0 31. 427 482 390 383 443 641 695 696 446 590 381 489 808
1830+063 000350.0 151857.5 2.0 42. 392 430 353 351 404 542 557 596 386 495 297 398 716
SS433 000644.5 152152.4 6.7 32. 432 486 413 395 454 621 655 653 439 558 351 459 800
noise 001335.5 152844.6 0.0 34. 396 448 358 353 408 601 647 649 410 559 351 458 774
1830+063 001439.5 152948.7 2.0 44. 339 385 298 295 340 500 562 539 335 453 260 356 637
...
1830+063 072914.5 224535.1 2.0 26. 427 488 400 387 444 635 690 676 442 582 359 463 792
SS433 073207.0 224828.1 6.7 36. 380 437 349 345 389 581 624 620 397 524 310 415 713
1830+063 073938.5 225600.8 2.0 23. 460 517 428 414 465 662 728 728 476 608 382 494 832
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Here, inspect if the antenna positions are indeed the ones obtained from those from the latest baseline solutions. See also Section 6.5.2. Also pay attention to the system temperatures, near rising and setting you might see some increased values, and some antennas are better than others, but there should be no outliers.