CA083 #2839 tar-save will be created 2000 Apr 18-19 Processing factor = ?? DOY 109-110 97% have fourfit Quality Codes of 5-9. Algonquin: No phase cal, so fringed with manual phases. Gilcreek: OK. HartRAO: OK. Hobart: High clock rate: 10 ps/s. Matera: Strong S-band RFI in ~8% of scans, particularly in channel S3. Tsukuba: OK. QC=5-9 AI 94% A - Gilcreek AT 97% G - Algonquin GA 98% H - Hobart HT 97% I - Matera JH 96% J - HartRAO T - Tsukuba ******************************************************************************* CA083 (2000 April 18-19) ======================== Correlator notes: Algonquin: No phase cal, so fringe with manual phases. Hobart: Clock rate 10 ps/s. Matera: Strong RFI in S channel 3 in some prepass scans. There are of order 70 scans in the production pass for which fringes are missing for all or part of the scan in a single channel. They appear to be due to a correlator fault of some sort and not to a station problem (e.g., RFI). Most are assigned 'G' error codes, but a few were identified only by looking for anomalous values of (channel fringe amp)/ (coherent fringe amp over channels). All will be reprocessed in the cleanup pass, along with other error code scans (B, D, and E), missed scans, short scans, all non-detections, and scans with zero pcal amp at stations other than Algonquin. Hobart/Tsukuba: Scattered over the first 5 hours of the observations there are ~10 scans for which the fringe amp in the lower 3 X channels is 20-40% lower than the mean amp, and conversely the amp in the upper 4 X channels is 20-40% higher. All are on either 1741-038 or 1908-201. See email correspondence between Dave Shaffer and Brian Corey below. Probably a source structure effect. Fourfitting dates: DOY 143-144 production pass DOY 154 repro pass DOY 167 3 scans with mismatched FRTs + 2 S-band E codes **************************************************************************** Station Mail: **************************************************************************** From: GSI VLBI group Date: Wed, 19 Apr 2000 02:04:30 +0900 To: ivs-ops@ivscc.gsfc.nasa.gov Subject: CA083 ready at Tsukuba32m Tsukuba32m is ready for CORE-A083. First source is 1357+769 at 18:00:00(UT). Sky is cloudy. Temp:9.67C, Hum:90%, Pres:1013.5hPa Formatter - GPS = +300 nsec at 18-Apr 16:56(UT). Tsys: X-band =48.6 K, S-band=67.9 K (EL=90) SEFD: X-band =290.816 Jy, S-band=362.905 Jy (Virgo-A, AZ=252.2, EL=43.1) All systems are normal. Sincerely, ====================================================== GSI VLBI group Geographical Survey Institute, Ministry of Construction Japan e-mail:gsi32m@gaos.gsi-mc.go.jp web:http://vldb.gsi-mc.go.jp/sokuchi/vlbi/english/ ====================================================== Date: Tue, 18 Apr 2000 19:27:33 +0200 (SAST) From: HartRAO VLBI Operator To: ivs-ops Subject: CA083 HartRAO is ready to start CA083. First source 0637-752 at 17:59:40 Clock offset 18.13 microseconds MASER late Weather clear, humidity at heads 35 % All systems normal Regards Ludwig Combrinck Date: Tue, 18 Apr 2000 17:35:35 +0000 (UTC) From: oper@blizzard.gcgo.nasa.gov (Gilmore Creek) To: ivs-ops@ivscc.gsfc.nasa.gov Subject: ca083, Gilmore Creek, Ready-message Session ca083 ready message for Gilmore Creek. ---------------------------------------------- Comments: Fairbanks is ready for ca083 start @ 1800ut. First source: 1357+769 at 180000 UT GPS-FMOUT: 7.2 microseconds Wx: Temperature (C): -4.1 Pressure (mBar): 957.9 Humidity (%): 30.3 Sky Conditions: Clear skies Cable difference is: longer cable makes the reading smaller by 697 microseconds and is nominal Pointing values: SEFD X/S Source Az/El Offset1 Offset2 637/703 cas-a 77/64 .015 .022 538/694 cygnus-a 175/65 .014 .027 Tsys (x1/s/x2): 58/58/51 Recorder Humidity (%): 20 Date: Tue, 18 Apr 2000 17:43:18 +0000 (GMT) From: Anthony Searle To: ivs-ops Subject: ARO ready for CA083 ARO is ready for CA083, waiting on source 1357+769 SEFDs 3c147 Az = 62.4 el = 51.8 X = 206.9 S = 209.7 3c123 Az = 102.7 el = 54.3 x = 199.7 S = 203.5 Wx: Overcast skies, light breeze, 4 C, 990.7 mB Humid = 51.9 % Recorder temp = 23 C Humid = 20% Formatter - GPS = -1.7345 us Phase cal is not working Cheers, Anthony Searle Geodetic Survey of Canada Ottawa, Ontario, Canada Internet: searle@geod.emr.ca From: "VLBI - ASI/CGS Matera" To: "ops bb" Subject: matera ready for corea 083 Date: Tue, 18 Apr 2000 19:58:24 +0200 Matera is ready for corea 083exp. We have partially cloudy sky. Source: Cas-a; Position(a/e): 11/71; Sefd(x/s):1161/1131; Tsys(x/s): 51/78; regards G.Nicoletti Matera Vlbi Team Date: Tue, 18 Apr 2000 17:59:40 +0000 (UTC) From: oper@blizzard.gcgo.nasa.gov (Gilmore Creek) To: ivs-ops@ivscc.gsfc.nasa.gov Subject: ca083, Gilmore Creek, Autostart-message Session ca083 ready message for Gilmore Creek. ---------------------------------------------- Started recording with source: 1357+769 at 109.17:59:40 UT From: "VLBI - ASI/CGS Matera" To: "ops bb" Subject: matera started corea83 Date: Tue, 18 Apr 2000 20:00:15 +0200 Matera started on time corea 83 experiment Gps-Mark IV=16.8 usec The recorder humidity is 38% regards G.Nicoletti Matera Vlbi Team From: GSI VLBI group Date: Wed, 19 Apr 2000 03:03:36 +0900 To: ivs-ops@ivscc.gsfc.nasa.gov Subject: CA083 start at Tsukuba32m Tsukuba32m started CORE-A083 on time. First source is 1357+769. Sky is cloudy. Temp:7.90C, Hum:96%, Pres:1013.2hPa Formatter - GPS = 310 nsec at 18-Apr 18:01(UT). All systems are normal. Sincerely, ====================================================== GSI VLBI group Geographical Survey Institute, Ministry of Construction Japan e-mail:gsi32m@gaos.gsi-mc.go.jp web:http://vldb.gsi-mc.go.jp/sokuchi/vlbi/english/ ====================================================== Date: Wed, 19 Apr 2000 04:14:13 +1000 (EST) From: David Legge Subject: Hobart has started experiment CA083 Hobart has started experiment CA083 ------------------------------------------------------------- The first scheduled source was 0637-752 @ 175940/109 UT/DOY Formatter (H-maser) leads GPS 37.9 microsec @ 1805/109 UT/DOY Cable Cal 779.0 microsec, shorter cable gives longer delay Tape recorder humidity 27 % relative at experiment start Weather and Sky: cool, 15 % cloud, 9 km/h wind at expt start Comments/Problems: none to report Regards, David Legge Date: Wed, 19 Apr 2000 18:02:41 +0000 (UTC) From: oper@blizzard.gcgo.nasa.gov (Gilmore Creek) To: ivs-ops@ivscc.gsfc.nasa.gov Subject: ca083, Gilmore Creek, Stop-message Session ca083 stop message for Gilmore Creek. --------------------------------------------- Comments: Fairbanks ends ca083 @ 1750ut. Missed 10 scans, from 2040 thru 2118ut due to tracking computer display failure. Tape: mailed to Haystack File: put in apr00 Problem scans: Source Scan start Explanation of problem 0003-066 2040 failure first source 2234+282 2116 failure last source Tape Inventory: 5 thin 0 thick Observation finished at: 1750 UT From: "VLBI - ASI/CGS Matera" To: "ops bb" Subject: Core-A 83 end Date: Wed, 19 Apr 2000 20:13:28 +0200 Matera station completed Core-A 83 without problems Start up measured delta time was Gps - MK IV = 16,80usec Completion delta time was Gps - MK IV = 17,08 usec Log file stored at CDDISA Tape label is OVLB0193,A01D The recorder humidity was 38% at start up; it was 35% at completion time Matera Vlbi Team From: GSI VLBI group Date: Thu, 20 Apr 2000 03:24:33 +0900 To: ivs-ops@ivscc.gsfc.nasa.gov Subject: CA083 finished at Tsukuba32m Tsukuba32m finished CORE-A083. All scans recorded. Sky is rainy. Temp:10.34C, Hum:91%, Pres:1012.3hPa Formatter - GPS = 310 nsec at 110-18:23 Tsys : X=63.9 K S=73.0 K (at El=90) SEFD : X=344.595 S=366.043 (at cygnus-a Az 69.2 El 58.7 ) We put the file "ca083ts.log" on vlbigeo@cddisa.gsfc.nasa.gov/apr00. ====================================================== GSI VLBI group Geographical Survey Institute, Ministry of Construction Japan e-mail:gsi32m@gaos.gsi-mc.go.jp web:http://vldb.gsi-mc.go.jp/sokuchi/vlbi/english/ ====================================================== From: Steve Farley Subject: ARO has ended ca083 To: ivs-ops@ivscc.gsfc.nasa.gov (ops) Date: Wed, 19 Apr 2000 18:26:37 GMT Algonquin has ended ca083, all sources observed. Formatter - gps = -1.755 us Sefd on 3c123 Az = 118.6 El = 63.5 X = 176.1 S = 204.7 Current weather is overcast with light winds, temp is 7.3 c, press is 988.7, humidity is 86.5 Tape drive is at 23 c and 23 % Tapes will be shipped Thursday April 20. Phase cal was not working for this experiment, cable length do not appeear to be correct(related problem) Log files will be down loaded to cddisa later today. Regards from the crew at ARO. -- Stephen Farley Geodetic Survey of Canada Ottawa, Ontario, Canada Internet: farley@geod.emr.ca Date: Thu, 20 Apr 2000 06:48:48 +1000 (EST) From: Lincoln Hanslow Subject: Hobart has completed CA083 Hobart has completed experiment ca083. -------------------------------------------------------------------- The PCFS log file has been put in directory apr00 on host cddisa. ------------------------------------------------ Tape Label UT start UT stop IRAM0148,FB9A 1800/109 0848/110 HS002820,8719 0857/110 1752/110 ------------------------------------------------ Formatter (H-maser) leads GPS 37.0 microsec @ 1815/110 UT/DOY. Cable Cal 724.2 microsec longer delay. Tape recorder humidity less than 20% relative at experiment end. Weather and Sky:partly overcast, fine, calm, and cool Comments/Problems:Parity errors a little high from about 1000/110UT onwards. Interference in VC14 as usual. Regards, Lincoln Hanslow. Date: Wed, 19 Apr 2000 18:17:24 -0400 From: Stephen Farley To: ops Subject: Tapes for ca083 Tapes for ca083 should leave Ottawa on Thursday April 20, via FedEX going to Haystack Obs. Two tapes s0000027, fca6 and ngs00315, 8ae2 Logfiles have been placed on cddisa/apr00 Have a good night. Stephen =========================================================== Stephen Farley Email farley@geod.nrcan.gc.ca Geodetic Survey Phone (613) 992-2236 Natural Resources Canada Date: Thu, 20 Apr 2000 08:55:45 +0200 (SAST) From: HartRAO VLBI Operator To: ivs-ops Subject: Complete ca083 HartRAO has completed ca083 with out any problems. Weather clear. Clock offset =18.48microsecs (MASER LATE) All systems were normal. Regards VLBI Team From bec Thu Jun 15 15:40:30 EDT 2000 From: Brian Corey Subject: weird sources To: dbs@gemini.gsfc.nasa.gov (Dave Shaffer) Date: Thu, 15 Jun 2000 15:40:30 EDT Hi Dave, What do you know about 1741-038 and 1908-201? In both CA082 (March 2000) and CA083 (April 2000), there is a strong frequency dependence to the Hobart/Tsukuba X-band fringe amplitudes on those two sources that is opposite to normal, i.e., the amplitudes roll off as you go down in frequency, not up. The table below gives the details on the 2 sources and on 2121+053 for comparison. Is it conceivable that the weaker amplitudes below ~8.6 GHz are a source structure effect?? I am reluctant to attribute it to source structure, particularly since the effect shows up on *two* sources on the same baseline around the same time. But I'm having a hard time coming up with an alternative explanation. So before I expend more effort searching for instrumental explanations, I wanted to run the evidence by you. Incidentally... - No other baselines to Tsukuba on the 2 sources show the rolloff, but then none of those observations is simultaneous with Hobart/Tsukuba. - The single other baseline/scan to Hobart on the 2 sources shows no rolloff. - Phase cal amplitudes at both stations are nearly identical on all sources. ==> It's not a Tsys effect. - I see nothing unusual in the fringe plots other than the rolloff. Given that IF1 feeds channels 1-4 and IF3 feeds 5-8, I would be suspicious of a problem in IF1, but even within each group (1-4 and 5-8), the rolloff is evident and is contrary to the normal pattern. --Brian # Hobart/Tsukuba X-band channel fringe amps for 3 sources in CA083 # # amp = 1.e5 * coherent fringe amplitude over all 8 channels # ampn = 1.e5 * fringe amplitude in X-band channel n # #DDD HH MM SNR amp amp1 amp2 amp3 amp4 amp5 amp6 amp7 amp8 source 109 18 49 61.7 151 87 100 123 155 177 188 186 196 1741-038 109 19 38 63.0 154 100 106 111 146 170 189 193 222 1741-038 109 20 22 60.4 148 93 104 116 133 180 187 183 192 1741-038 109 21 08 58.7 143 95 99 110 147 171 181 174 173 1741-038 109 22 17 54.6 132 97 99 93 122 158 168 177 144 1741-038 109 18 44 35.8 130 110 108 121 136 143 150 128 152 1908-201 109 19 34 33.5 118 100 98 110 116 124 137 121 151 1908-201 109 20 19 36.3 127 108 105 109 123 148 136 154 134 1908-201 109 21 21 34.2 119 116 117 111 104 142 134 125 111 1908-201 109 23 58 30.6 105 93 93 89 114 109 123 115 108 1908-201 110 16 28 27.2 103 75 81 97 103 110 123 124 112 1908-201 109 18 23 126.8 480 527 518 497 509 492 466 444 393 2121+053 109 19 11 134.5 507 538 546 516 534 514 507 429 473 2121+053 109 19 53 136.5 512 540 533 530 537 518 490 472 481 2121+053 109 20 32 139.3 525 521 594 561 552 541 524 445 463 2121+053 109 21 14 148.8 564 590 603 592 576 578 544 518 513 2121+053 109 21 54 143.9 541 565 574 578 570 535 537 473 506 2121+053 109 22 31 144.9 548 581 579 578 565 559 521 498 511 2121+053 109 23 03 145.8 553 600 576 584 550 564 528 512 521 2121+053 109 23 47 142.4 537 557 575 565 557 525 534 484 502 2121+053 110 21 00 140.3 528 540 570 575 525 514 517 480 509 2121+053 110 57 00 131.4 506 531 538 525 519 508 487 455 484 2121+053 110 01 33 122.4 465 526 507 508 462 467 465 414 378 2121+053 110 02 08 120.9 456 483 492 468 469 476 459 422 385 2121+053 110 16 54 100.3 376 409 404 412 396 362 344 324 363 2121+053 110 17 38 95.1 360 421 393 388 367 364 344 319 291 2121+053 Date: Thu, 15 Jun 2000 18:27:49 -0400 (EDT) From: Dave Shaffer To: bec@haystack.mit.edu, dbs@gemini.gsfc.nasa.gov Subject: Re: weird sources Brian, I would not be surprised if you are seeing source structure effects. I will have to look at the actual fringe amp data, perhaps with some augmented model-fitting capability, to tell for sure. However, the models for both of these sources are extended, in position angle 178 for 1741-038 and PA 172 for 1908-201. (See the latest source.cat used for SKED.) These PAs result from single component fits (i.e. to an elliptical model), but I wouldn't be surprised at nearly-equal double models (in the same PA). Since I use only amplitudes and not phases for my model fitting, I can not tell up from down (or left from right) in my source models. I therefore constrain myself to assigning a PA in the range from 0 to 180 for all sources. The (u,v) track for the Hobart-Tsukuba baseline for all three of these sources (i.e. including 2121+053) (and any others at these decs, too, of course) covers only a very narrow range of position angles in the vicinity of 0 (or 180, which you can't differentiate without phases, as noted above!). Thus, the (u,v) coverage is where one might most expect to see structure effects. The other thing to note from the model catalog is the relative strength of the sources. The total flux density in 1741-038 is about 4 Jy, and 1908-201 has about 2.8 Jy, versus only about 1.5 Jy for 2121+053, yet the fringe amplitudes for 2121+053 are MUCH bigger than for 1741-038 or 1908-201. Thus, I suspect we are observing close to a structure minimum for the two "weird" sources. A quick hand plot of the amplitudes for 1741-038 versus frequency is not a bad eyeball fit for the case where the line of first minimum for an equal double source falls just interior (i.e. closer to the origin of the (u,v)-plane) to the observing paths (i.e. the multiple (u,v)-tracks which result from the BWS sequence). I'll check some old data, as well as the CORE-A82 and -83 data when they are available, to try to solidify this interpretation. Unless you get a different story from me then, it's probably not worth your while to try to track down any other causes! Dave