COVER INFORMATION Station: VLBA_NL (Code Nl ) Experiment: Confirming the first detection of a merging dual SMBH system at high-z Exp. Code: gs044a Schedule Version: 2.00 Processed by SCHED version: 11.50 Development version 11.5. Started Apr. 2 PI: Cristiana Spingola Address: University of Bologna - INAF-IRA via Gobetti 101 40129 Bologna Italy Phone: +39 3938231373 EMAIL: spingola@ira.inaf.it Fax: Phone during observation: Observing mode: Notes: v2: T6 IF C->B, BBC 9-12 -> 5-8 Ar confirms BBC tunings for their RDBE COVER LETTER: Schedule for VLBA_NL (Code Nl ) Page 2 Confirming the first detection of a merging dual SMBH system at high-z UP: D => Below limits; H => Below horizon mask; W => still slewing at end; blank => Up. Early: Seconds between end of slew and start. Dwell: On source seconds. Disk: GBytes recorded to this point. TPStart: Recording start time. Frequencies are LO sum (band edge). SYNC: Time correlator is expected to sync up. ---------------------------------------------------------------------------------------- Start UT Source Start / Stop Early Disk TPStart Stop UT LST EL AZ HA UP ParA Dwell GBytes SYNC ---------------------------------------------------------------------------------------- --- Sat 26 Oct 2019 Day 299 --- Next scan frequencies: 4860.25 4860.25 4892.25 4892.25 4924.25 4924.25 4956.25 4956.25 Next BBC frequencies: 760.25 760.25 792.25 792.25 824.25 824.25 856.25 856.25 Next scan bandwidths: 32.00 32.00 32.00 32.00 32.00 32.00 32.00 32.00 17 37 40 MG2016 13 50 36 2.2 76.5 -6.5 D -47.7 0 0 17 37 40 17 41 10 --- 13 54 07 2.9 77.1 -6.4 -47.9 0 27 17 37 41 17 42 40 MG2016 13 55 37 3.1 77.3 -6.4 -48.0 84 27 17 42 40 17 46 10 --- 13 59 07 3.8 77.9 -6.4 -48.1 210 54 17 42 41 17 46 50 J2018+0831 13 59 47 2.1 80.4 -6.3 D -48.0 29 54 17 46 50 17 47 50 --- 14 00 48 2.3 80.5 -6.3 H -48.1 0 62 17 46 51 17 47 50 MG2016 14 00 48 4.1 78.2 -6.3 -48.2 -12 62 17 48 02 17 51 20 --- 14 04 18 4.7 78.8 -6.3 -48.3 198 87 17 47 51 17 51 20 J2018+0831 14 04 18 3.0 81.1 -6.2 H -48.2 -12 87 17 51 32 17 52 50 --- 14 05 48 3.3 81.4 -6.2 H -48.2 0 97 17 51 21 17 52 50 MG2016 14 05 48 5.0 79.0 -6.2 -48.3 -12 97 17 53 02 17 56 20 --- 14 09 19 5.6 79.6 -6.2 -48.5 198 123 17 52 51 17 57 00 J2018+0831 14 09 59 4.0 82.1 -6.2 H -48.3 28 123 17 57 00 17 58 00 --- 14 10 59 4.2 82.2 -6.1 H -48.4 0 131 17 57 01 17 58 00 MG2016 14 10 59 5.9 79.9 -6.2 -48.5 -12 131 17 58 12 18 01 30 --- 14 14 30 6.6 80.4 -6.1 -48.6 198 156 17 58 01 18 01 30 J2018+0831 14 14 30 4.9 82.8 -6.1 -48.4 -12 156 18 01 42 18 03 00 --- 14 16 00 5.1 83.1 -6.1 -48.5 78 166 18 01 31 18 03 00 MG2016 14 16 00 6.9 80.7 -6.1 -48.7 -12 166 18 03 12 18 06 30 --- 14 19 31 7.5 81.2 -6.0 -48.8 198 192 18 03 01 18 07 10 J2018+0831 14 20 11 5.9 83.7 -6.0 -48.6 29 192 18 07 10 18 08 10 --- 14 21 11 6.1 83.9 -6.0 -48.6 60 199 18 07 11 18 08 10 MG2016 14 21 11 7.8 81.5 -6.0 -48.8 -12 199 18 08 22 18 11 40 --- 14 24 42 8.5 82.1 -5.9 -48.9 198 225 18 08 11 18 11 40 J2018+0831 14 24 42 6.7 84.5 -5.9 -48.7 -11 225 18 11 51 18 13 10 --- 14 26 12 7.0 84.7 -5.9 -48.7 79 235 18 11 41 18 13 10 MG2016 14 26 12 8.7 82.3 -5.9 -49.0 -12 235 18 13 22 18 16 40 --- 14 29 42 9.4 82.9 -5.8 -49.1 198 261 18 13 11 Schedule for VLBA_NL (Code Nl ) Page 3 Confirming the first detection of a merging dual SMBH system at high-z UP: D => Below limits; H => Below horizon mask; W => still slewing at end; blank => Up. Early: Seconds between end of slew and start. Dwell: On source seconds. Disk: GBytes recorded to this point. TPStart: Recording start time. Frequencies are LO sum (band edge). SYNC: Time correlator is expected to sync up. ---------------------------------------------------------------------------------------- Start UT Source Start / Stop Early Disk TPStart Stop UT LST EL AZ HA UP ParA Dwell GBytes SYNC ---------------------------------------------------------------------------------------- --- Sat 26 Oct 2019 Day 299 --- 18 17 20 J2018+0831 14 30 22 7.8 85.4 -5.8 -48.8 29 261 18 17 20 18 18 20 --- 14 31 23 8.0 85.6 -5.8 -48.8 60 268 18 17 21 18 18 20 MG2016 14 31 23 9.7 83.2 -5.8 -49.1 -12 268 18 18 32 18 21 50 --- 14 34 53 10.4 83.7 -5.8 -49.2 198 294 18 18 21 18 21 50 J2018+0831 14 34 53 8.6 86.2 -5.7 -48.8 -11 294 18 22 01 18 23 20 --- 14 36 23 8.9 86.4 -5.7 -48.8 79 304 18 21 51 18 23 20 MG2016 14 36 23 10.6 84.0 -5.7 -49.2 -12 304 18 23 32 18 26 50 --- 14 39 54 11.3 84.6 -5.7 -49.3 198 330 18 23 21 18 27 30 J2018+0831 14 40 34 9.7 87.1 -5.6 -48.9 29 330 18 27 30 18 28 30 --- 14 41 34 9.9 87.3 -5.6 -48.9 60 337 18 27 31 18 28 30 MG2016 14 41 34 11.6 84.8 -5.6 -49.3 -12 337 18 28 42 18 32 00 --- 14 45 05 12.2 85.4 -5.6 -49.3 198 363 18 28 31 18 32 00 J2018+0831 14 45 05 10.5 87.8 -5.6 -48.9 -11 363 18 32 11 18 33 30 --- 14 46 35 10.8 88.1 -5.5 -48.9 79 373 18 32 01 18 33 30 MG2016 14 46 35 12.5 85.7 -5.6 -49.4 -12 373 18 33 42 18 37 00 --- 14 50 06 13.2 86.2 -5.5 -49.4 198 398 18 33 31 18 37 40 J2018+0831 14 50 46 11.6 88.8 -5.5 -48.9 29 398 18 37 40 18 38 40 --- 14 51 46 11.8 88.9 -5.5 -49.0 60 406 18 37 41 18 38 40 MG2016 14 51 46 13.5 86.5 -5.5 -49.4 -12 406 18 38 52 18 42 10 --- 14 55 17 14.1 87.1 -5.4 -49.5 198 432 18 38 41 18 42 10 J2018+0831 14 55 17 12.4 89.5 -5.4 -49.0 -11 432 18 42 21 18 43 40 --- 14 56 47 12.7 89.8 -5.4 -49.0 79 442 18 42 11 18 43 40 MG2016 14 56 47 14.4 87.3 -5.4 -49.5 -12 442 18 43 52 18 47 10 --- 15 00 17 15.1 87.9 -5.3 -49.5 198 467 18 43 41 18 47 50 J2018+0831 15 00 58 13.5 90.5 -5.3 -49.0 29 467 18 47 50 18 48 50 --- 15 01 58 13.7 90.6 -5.3 -49.0 60 475 18 47 51 18 48 50 MG2016 15 01 58 15.4 88.2 -5.3 -49.5 -12 475 18 49 02 18 52 20 --- 15 05 28 16.0 88.8 -5.2 -49.5 198 501 18 48 51 18 52 20 J2018+0831 15 05 28 14.3 91.2 -5.2 -48.9 -11 501 18 52 31 18 53 50 --- 15 06 58 14.6 91.5 -5.2 -48.9 79 511 18 52 21 Schedule for VLBA_NL (Code Nl ) Page 4 Confirming the first detection of a merging dual SMBH system at high-z UP: D => Below limits; H => Below horizon mask; W => still slewing at end; blank => Up. Early: Seconds between end of slew and start. Dwell: On source seconds. Disk: GBytes recorded to this point. TPStart: Recording start time. Frequencies are LO sum (band edge). SYNC: Time correlator is expected to sync up. ---------------------------------------------------------------------------------------- Start UT Source Start / Stop Early Disk TPStart Stop UT LST EL AZ HA UP ParA Dwell GBytes SYNC ---------------------------------------------------------------------------------------- --- Sat 26 Oct 2019 Day 299 --- 18 53 50 MG2016 15 06 58 16.3 89.0 -5.2 -49.6 -12 511 18 54 02 18 57 20 --- 15 10 29 17.0 89.6 -5.2 -49.6 198 536 18 53 51 18 58 00 J2018+0831 15 11 09 15.4 92.2 -5.1 -48.9 29 536 18 58 00 18 59 00 --- 15 12 09 15.6 92.4 -5.1 -48.9 60 544 18 58 01 18 59 00 MG2016 15 12 09 17.3 89.9 -5.1 -49.6 -12 544 18 59 12 19 02 30 --- 15 15 40 17.9 90.4 -5.1 -49.6 198 570 18 59 01 19 02 30 J2018+0831 15 15 40 16.2 92.9 -5.1 -48.9 -11 570 19 02 41 19 04 00 --- 15 17 10 16.5 93.2 -5.0 -48.9 79 580 19 02 31 19 04 00 MG2016 15 17 10 18.2 90.7 -5.1 -49.6 -12 580 19 04 12 19 07 30 --- 15 20 41 18.9 91.3 -5.0 -49.5 198 605 19 04 01 19 08 10 J2018+0831 15 21 21 17.3 93.9 -5.0 -48.8 29 605 19 08 10 19 09 10 --- 15 22 21 17.5 94.1 -4.9 -48.8 60 613 19 08 11 19 09 10 MG2016 15 22 21 19.2 91.6 -5.0 -49.5 -12 613 19 09 22 19 12 40 --- 15 25 52 19.8 92.2 -4.9 -49.5 198 638 19 09 11 19 12 40 J2018+0831 15 25 52 18.1 94.7 -4.9 -48.7 -11 638 19 12 51 19 14 10 --- 15 27 22 18.4 94.9 -4.9 -48.7 79 649 19 12 41 19 14 10 MG2016 15 27 22 20.1 92.4 -4.9 -49.5 -12 649 19 14 22 19 17 40 --- 15 30 52 20.8 93.0 -4.8 -49.5 198 674 19 14 11 19 18 20 J2018+0831 15 31 33 19.2 95.7 -4.8 -48.6 29 674 19 18 20 19 19 20 --- 15 32 33 19.4 95.8 -4.8 -48.6 60 682 19 18 21 19 19 20 MG2016 15 32 33 21.1 93.3 -4.8 -49.5 -12 682 19 19 32 19 22 50 --- 15 36 03 21.7 93.9 -4.7 -49.4 198 707 19 19 21 19 22 50 J2018+0831 15 36 03 20.0 96.4 -4.7 -48.5 -11 707 19 23 01 19 24 20 --- 15 37 34 20.3 96.7 -4.7 -48.5 79 718 19 22 51 19 24 20 MG2016 15 37 34 22.0 94.2 -4.7 -49.4 -12 718 19 24 32 19 27 50 --- 15 41 04 22.7 94.8 -4.7 -49.3 198 743 19 24 21 19 28 30 J2018+0831 15 41 44 21.1 97.4 -4.6 -48.4 29 743 19 28 30 19 29 30 --- 15 42 44 21.3 97.6 -4.6 -48.4 60 751 19 28 31 19 36 10 MG2016 15 49 25 24.2 96.2 -4.5 -49.2 388 751 19 36 10 19 39 40 --- 15 52 56 24.9 96.8 -4.5 -49.1 210 778 19 36 11 Schedule for VLBA_NL (Code Nl ) Page 5 Confirming the first detection of a merging dual SMBH system at high-z UP: D => Below limits; H => Below horizon mask; W => still slewing at end; blank => Up. Early: Seconds between end of slew and start. Dwell: On source seconds. Disk: GBytes recorded to this point. TPStart: Recording start time. Frequencies are LO sum (band edge). SYNC: Time correlator is expected to sync up. ---------------------------------------------------------------------------------------- Start UT Source Start / Stop Early Disk TPStart Stop UT LST EL AZ HA UP ParA Dwell GBytes SYNC ---------------------------------------------------------------------------------------- --- Sat 26 Oct 2019 Day 299 --- 19 39 40 J2018+0831 15 52 56 23.1 99.4 -4.4 -48.1 -11 778 19 39 51 19 41 10 --- 15 54 26 23.4 99.7 -4.4 -48.0 79 788 19 39 41 19 41 10 MG2016 15 54 26 25.2 97.1 -4.4 -49.1 -12 788 19 41 22 19 44 40 --- 15 57 57 25.8 97.7 -4.4 -49.0 198 813 19 41 11 19 45 20 J2018+0831 15 58 37 24.2 100.5 -4.3 -47.9 28 813 19 45 20 19 46 20 --- 15 59 37 24.4 100.6 -4.3 -47.8 60 821 19 45 21 19 46 20 MG2016 15 59 37 26.1 98.0 -4.3 -48.9 -12 821 19 46 32 19 49 50 --- 16 03 08 26.8 98.7 -4.3 -48.8 198 847 19 46 21 19 49 50 J2018+0831 16 03 08 25.0 101.3 -4.3 -47.7 -12 847 19 50 02 19 51 20 --- 16 04 38 25.3 101.6 -4.2 -47.6 78 857 19 49 51 19 51 20 MG2016 16 04 38 27.0 98.9 -4.3 -48.8 -12 857 19 51 32 19 54 50 --- 16 08 09 27.7 99.6 -4.2 -48.6 198 882 19 51 21 19 55 30 J2018+0831 16 08 49 26.1 102.3 -4.2 -47.5 28 882 19 55 30 19 56 30 --- 16 09 49 26.2 102.5 -4.2 -47.4 60 890 19 55 31 19 56 30 MG2016 16 09 49 28.0 99.9 -4.2 -48.6 -12 890 19 56 42 20 00 00 --- 16 13 19 28.6 100.5 -4.1 -48.4 198 916 19 56 31 20 00 00 J2018+0831 16 13 19 26.9 103.2 -4.1 -47.3 -12 916 20 00 12 20 01 30 --- 16 14 50 27.1 103.5 -4.1 -47.2 78 926 20 00 01 20 01 30 MG2016 16 14 50 28.9 100.8 -4.1 -48.4 -12 926 20 01 42 20 05 00 --- 16 18 20 29.6 101.5 -4.0 -48.2 198 951 20 01 31 20 05 40 J2018+0831 16 19 00 27.9 104.3 -4.0 -47.0 28 951 20 05 40 20 06 40 --- 16 20 00 28.1 104.4 -4.0 -46.9 60 959 20 05 41 20 06 40 MG2016 16 20 00 29.9 101.8 -4.0 -48.2 -12 959 20 06 52 20 10 10 --- 16 23 31 30.5 102.4 -3.9 -48.0 198 984 20 06 41 20 10 10 J2018+0831 16 23 31 28.7 105.1 -3.9 -46.7 -12 984 20 10 22 20 11 40 --- 16 25 01 29.0 105.4 -3.9 -46.6 78 994 20 10 11 20 11 40 MG2016 16 25 01 30.8 102.7 -3.9 -47.9 -12 994 20 11 52 20 15 10 --- 16 28 32 31.4 103.4 -3.9 -47.8 198 1020 20 11 41 20 15 50 J2018+0831 16 29 12 29.7 106.2 -3.8 -46.4 28 1020 20 15 50 20 16 50 --- 16 30 12 29.9 106.4 -3.8 -46.3 60 1028 20 15 51 Schedule for VLBA_NL (Code Nl ) Page 6 Confirming the first detection of a merging dual SMBH system at high-z UP: D => Below limits; H => Below horizon mask; W => still slewing at end; blank => Up. Early: Seconds between end of slew and start. Dwell: On source seconds. Disk: GBytes recorded to this point. TPStart: Recording start time. Frequencies are LO sum (band edge). SYNC: Time correlator is expected to sync up. ---------------------------------------------------------------------------------------- Start UT Source Start / Stop Early Disk TPStart Stop UT LST EL AZ HA UP ParA Dwell GBytes SYNC ---------------------------------------------------------------------------------------- --- Sat 26 Oct 2019 Day 299 --- 20 16 50 MG2016 16 30 12 31.7 103.7 -3.8 -47.7 -12 1028 20 17 02 20 20 20 --- 16 33 43 32.3 104.4 -3.8 -47.5 198 1053 20 16 51 20 20 20 J2018+0831 16 33 43 30.5 107.1 -3.8 -46.1 -12 1053 20 20 32 20 21 50 --- 16 35 13 30.8 107.4 -3.7 -46.0 78 1063 20 20 21 20 21 50 MG2016 16 35 13 32.6 104.7 -3.8 -47.4 -12 1063 20 22 02 20 25 20 --- 16 38 44 33.2 105.4 -3.7 -47.2 198 1089 20 21 51 20 26 00 J2018+0831 16 39 24 31.5 108.3 -3.7 -45.8 28 1089 20 26 00 20 27 00 --- 16 40 24 31.7 108.5 -3.6 -45.7 60 1096 20 26 01 20 27 00 MG2016 16 40 24 33.5 105.7 -3.7 -47.1 -12 1096 20 27 12 20 30 30 --- 16 43 54 34.2 106.4 -3.6 -46.9 198 1122 20 27 01 20 30 30 J2018+0831 16 43 54 32.3 109.2 -3.6 -45.4 -12 1122 20 30 42 20 32 00 --- 16 45 25 32.6 109.5 -3.6 -45.3 78 1132 20 30 31 20 32 00 MG2016 16 45 25 34.4 106.7 -3.6 -46.8 -12 1132 20 32 12 20 35 30 --- 16 48 55 35.1 107.5 -3.5 -46.6 198 1157 20 32 01 20 36 10 J2018+0831 16 49 35 33.3 110.4 -3.5 -45.0 28 1157 20 36 10 20 37 10 --- 16 50 35 33.5 110.6 -3.5 -44.9 60 1165 20 36 11 20 37 10 MG2016 16 50 35 35.4 107.8 -3.5 -46.4 -12 1165 20 37 22 20 40 40 --- 16 54 06 36.0 108.5 -3.4 -46.2 198 1191 20 37 11 20 41 20 J2018+0831 16 54 46 34.2 111.4 -3.4 -44.6 28 1191 20 41 20 20 42 20 --- 16 55 46 34.4 111.7 -3.4 -44.5 60 1198 20 41 21 20 42 20 MG2016 16 55 46 36.3 108.9 -3.4 -46.1 -12 1198 20 42 32 20 45 50 --- 16 59 17 36.9 109.6 -3.3 -45.8 198 1224 20 42 21 20 45 50 J2018+0831 16 59 17 35.0 112.4 -3.3 -44.2 -12 1224 20 46 02 20 47 20 --- 17 00 47 35.3 112.7 -3.3 -44.1 78 1234 20 45 51 20 47 20 MG2016 17 00 47 37.2 109.9 -3.3 -45.7 -12 1234 20 47 32 20 50 50 --- 17 04 18 37.8 110.7 -3.3 -45.4 198 1259 20 47 21 20 51 30 J2018+0831 17 04 58 36.0 113.7 -3.2 -43.7 28 1259 20 51 30 20 52 30 --- 17 05 58 36.2 113.9 -3.2 -43.6 60 1267 20 51 31 20 52 30 MG2016 17 05 58 38.1 111.1 -3.2 -45.3 -12 1267 20 52 42 20 56 00 --- 17 09 29 38.7 111.8 -3.2 -44.9 198 1293 20 52 31 Schedule for VLBA_NL (Code Nl ) Page 7 Confirming the first detection of a merging dual SMBH system at high-z UP: D => Below limits; H => Below horizon mask; W => still slewing at end; blank => Up. Early: Seconds between end of slew and start. Dwell: On source seconds. Disk: GBytes recorded to this point. TPStart: Recording start time. Frequencies are LO sum (band edge). SYNC: Time correlator is expected to sync up. ---------------------------------------------------------------------------------------- Start UT Source Start / Stop Early Disk TPStart Stop UT LST EL AZ HA UP ParA Dwell GBytes SYNC ---------------------------------------------------------------------------------------- --- Sat 26 Oct 2019 Day 299 --- 20 56 30 J2018+0831 17 09 59 36.9 114.8 -3.2 -43.2 18 1293 20 56 30 21 00 00 --- 17 13 29 37.4 115.6 -3.1 -42.9 210 1320 20 56 31 SETUP FILE INFORMATION: NOTE: If DOPPLER, FREQ, or BW were used, see the individual scans for the final BBC settings. ======== Setup file: sess319.C1024glob Matching groups in /home/guest/rmc/SCHED/sched11.5/catalogs/freq_RDBE.dat: vc_d Setup group: 4 Station: VLBA_NL Total bit rate: 1024 Format: VDIF Bits per sample: 2 Sample rate: 64.000 Number of channels: 8 DBE type: RDBE_DDC Speedup factor: 1.00 Disk used to record data. 1st LO= 4100.00 4100.00 4100.00 4100.00 4100.00 4100.00 4100.00 4100.00 Net SB= U U U U U U U U IF SB = U U U U U U U U Pol. = RCP LCP RCP LCP RCP LCP RCP LCP BBC = 1 2 3 4 5 6 7 8 BBC SB= U U U U U U U U IF = A C A C A C A C VLBA FE= 6cm omit 6cm omit VLBA Synth= 13.6 4.1 13.6 The following frequency sets based on these setups were used. See the crd files for VLBA legacy system setups and pcal detection details. Frequency Set: 15 Setup file default. Used with PCAL = off LO sum= 4860.25 4860.25 4892.25 4892.25 4924.25 4924.25 4956.25 4956.25 BBC fr= 760.25 760.25 792.25 792.25 824.25 824.25 856.25 856.25 Bandwd= 32.00 32.00 32.00 32.00 32.00 32.00 32.00 32.00 VLBA legacy crd files using 4 channels based on RDBE channels: 3 4 5 6 CRD fr= 800.25 800.25 832.25 832.25 CRD bw= 16.00 16.00 16.00 16.00 Matching frequency sets: 15 16 18 19 20 21 22 23 24 Track assignments are: track1= 1, 2, 3, 4, 5, 6, 7, 8 barrel=roll_off POSITIONS OF SOURCES USED IN RECORDING SCANS Source Source position (RA/Dec) Error (B1950) (J2000) (Date) (mas) * MG2016 20 16 55.378166 * 20 19 18.092000 20 20 13.565900 0.00 11 17 44.97966 * 11 27 13.00000 11 31 08.04992 0.00 From catalog imbedded in main SCHED input file. * 3C345 16 41 17.606162 * 16 42 58.809900 16 43 36.764649 0.00 39 54 10.81394 * 39 48 36.99300 39 46 42.73413 0.00 From catalog imbedded in main SCHED input file. * J2018+0831 20 15 45.733430 * 20 18 11.311946 20 19 07.886706 0.00 08 22 30.62230 * 08 31 54.54739 08 35 47.14317 0.00 From catalog imbedded in main SCHED input file. SOURCE SCAN SUMMARY FOR SOURCES LISTED ABOVE Scan hours are for recording scans only. Baseline hours are only counted for scans above horizon at both ends. Source Setup file Frequency sets Observing hours (duplicates not shown) Scan Baseline MG2016 sess319.C1024glob 1 2 3 4 5 6 7 8 9 10 11 15 + 6.650 489.300 3C345 sess319.C1024glob 1 2 3 4 5 6 7 8 9 10 11 0.225 6.793 J2018+0831 sess319.C1024glob 1 2 3 4 5 6 7 8 9 10 11 15 + 2.525 164.241 EFFECT OF SOLAR CORONA The solar corona can cause unstable phases for sources too close to the Sun. SCHED provides warnings at individual scans for distances less than 10 degrees. The distance from the Sun to each source in this schedule is: Source Sun distance (deg) MG2016 96.6 3C345 64.2 J2018+0831 95.8 Barry Clark estimates from predictions by Ketan Desai of IPM scattering sizes that the Sun will cause amplitude reductions on the longest VLBA baselines at a solar distance of 60deg F^(-0.6) where F is in GHz. For common VLBI bands, this is: 327 MHz 117. deg 610 MHz 81. deg 1.6 GHz 45. deg 2.3 GHz 36. deg 5.0 GHz 23. deg 8.4 GHz 17. deg 15.0 GHz 12. deg 22.0 GHz 9. deg 43.0 GHz 6. deg