COVER INFORMATION Station: VLBA_FD (Code Fd ) Experiment: IGR J1746-321 ToO Exp. Code: BM197B Schedule Version: 1.00 Processed by SCHED version: Release of 02 July 2002 PI: Amy Mioduszewski Address: NRAO P. O. Box O Socorro, NM 87801 USA Phone: 505-835-7263 EMAIL: amiodusz@nrao.edu Fax: 505-835-7027 Phone during observation: 505-838-0393 Observing mode: VLBA Notes: Target of Opportunity Schedule for VLBA_FD (Code Fd ) Page 2 IGR J1746-321 ToO UP: D => Below limits; H => Below horizon mask. blank => Up. Early: Seconds between end of slew and start. Dwell: On source seconds. Tapes: Drive, Index, Start footage / Direction, Head Group, End footage. TPStart: Tape motion start time. Frequencies are LO sum (band edge). Automatic tape allocation specified. Tape positions are just estimates. ---------------------------------------------------------------------------------------- Start UT Source Start / Stop Early Tapes TPStart Stop UT LST EL AZ HA UP ParA Dwell (see above) ---------------------------------------------------------------------------------------- --- Tue 8 Apr 2003 Day 98 --- Next scan frequencies: 15349.49 15349.49 15357.49 15357.49 15365.49 15365.49 15373.49 15373.49 Next BBC frequencies: 749.49 749.49 757.49 757.49 765.49 765.49 773.49 773.49 Next scan bandwidths: 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 11 02 00 J1733-1304 17 11 25 46.0 172.3 -0.4 -6.8 0 1 1 0 11 02 00 11 03 00 --- 17 12 25 46.0 172.7 -0.3 -6.4 60 F 1 800 11 03 00 I1746-321 17 12 25 26.6 172.0 -0.6 -8.2 -45 1 1 800 11 03 00 11 05 00 --- 17 14 25 26.7 172.4 -0.5 -7.7 75 F 1 2400 11 05 00 W109 17 14 25 29.7 171.3 -0.6 -8.5 -12 1 1 2400 11 05 00 11 06 00 --- 17 15 25 29.7 171.6 -0.6 -8.3 48 F 1 3200 11 06 00 I1746-321 17 15 25 26.7 172.7 -0.5 -7.5 -12 1 1 3200 11 06 00 11 08 00 --- 17 17 26 26.8 173.1 -0.5 -7.0 108 F 1 4800 11 08 00 W109 17 17 26 29.8 172.1 -0.5 -7.8 -12 1 1 4800 11 08 00 11 09 00 --- 17 18 26 29.8 172.3 -0.5 -7.6 48 F 1 5600 11 09 00 I1746-321 17 18 26 26.8 173.4 -0.5 -6.8 -12 1 1 5600 11 09 00 11 11 00 --- 17 20 26 26.8 173.8 -0.4 -6.3 108 F 1 7200 11 11 00 W109 17 20 26 29.9 172.8 -0.5 -7.1 -12 1 1 7200 11 11 00 11 12 00 --- 17 21 26 29.9 173.1 -0.5 -6.8 48 F 1 8000 11 12 00 I1746-321 17 21 26 26.9 174.1 -0.4 -6.0 -12 1 1 8000 11 12 00 11 14 00 --- 17 23 27 26.9 174.5 -0.4 -5.6 108 F 1 9600 11 14 00 W109 17 23 27 29.9 173.6 -0.4 -6.3 -12 1 1 9600 11 14 00 11 15 00 --- 17 24 27 30.0 173.8 -0.4 -6.1 48 F 1 10400 11 15 00 I1746-321 17 24 27 26.9 174.8 -0.4 -5.3 -12 1 1 10400 11 15 00 11 17 30 --- 17 26 57 27.0 175.4 -0.3 -4.7 138 F 1 12400 11 17 30 GC441 17 26 57 29.8 176.5 -0.2 -3.5 -12 1 1 12400 11 17 30 11 18 30 --- 17 27 58 29.8 176.7 -0.2 -3.3 48 F 1 13200 11 18 30 I1746-321 17 27 58 27.0 175.6 -0.3 -4.5 -12 1 1 13200 11 18 30 11 20 30 --- 17 29 58 27.0 176.1 -0.3 -4.0 108 F 1 14800 Schedule for VLBA_FD (Code Fd ) Page 3 IGR J1746-321 ToO UP: D => Below limits; H => Below horizon mask. blank => Up. Early: Seconds between end of slew and start. Dwell: On source seconds. Tapes: Drive, Index, Start footage / Direction, Head Group, End footage. TPStart: Tape motion start time. Frequencies are LO sum (band edge). Automatic tape allocation specified. Tape positions are just estimates. ---------------------------------------------------------------------------------------- Start UT Source Start / Stop Early Tapes TPStart Stop UT LST EL AZ HA UP ParA Dwell (see above) ---------------------------------------------------------------------------------------- --- Tue 8 Apr 2003 Day 98 --- 11 20 30 GC441 17 29 58 29.8 177.2 -0.2 -2.8 -12 1 1 14800 11 20 30 11 21 30 --- 17 30 58 29.8 177.5 -0.2 -2.5 48 F 1 15600 11 21 30 W56 17 30 58 30.9 176.1 -0.3 -3.8 -8 1 1 15600 11 21 30 11 22 30 --- 17 31 58 30.9 176.4 -0.2 -3.5 52 F 1 16400 11 24 30 J1733-1304 17 33 59 46.3 180.3 0.0 0.2 83 1 1 16400 11 24 30 11 25 30 --- 17 34 59 46.3 180.6 0.0 0.5 60 F 1 17200 11 25 30 I1746-321 17 34 59 27.1 177.3 -0.2 -2.8 -44 1 2 17200 11 25 30 11 27 30 --- 17 36 59 27.1 177.7 -0.2 -2.3 76 R 1 15600 11 27 30 W109 17 36 59 30.2 177.0 -0.2 -3.0 -12 1 2 15600 11 27 30 11 28 30 --- 17 37 59 30.2 177.2 -0.2 -2.7 48 R 1 14800 11 28 30 I1746-321 17 37 59 27.1 178.0 -0.1 -2.0 -12 1 2 14800 11 28 30 11 30 30 --- 17 39 59 27.1 178.5 -0.1 -1.6 108 R 1 13200 11 30 30 W109 17 39 59 30.2 177.7 -0.1 -2.2 -12 1 2 13200 11 30 30 11 31 30 --- 17 41 00 30.2 178.0 -0.1 -2.0 48 R 1 12400 11 31 30 I1746-321 17 41 00 27.1 178.7 -0.1 -1.3 -12 1 2 12400 11 31 30 11 33 30 --- 17 43 00 27.1 179.2 -0.1 -0.8 108 R 1 10800 11 33 30 W109 17 43 00 30.2 178.5 -0.1 -1.5 -12 1 2 10800 11 33 30 11 34 30 --- 17 44 00 30.2 178.7 -0.1 -1.2 48 R 1 10000 11 34 30 I1746-321 17 44 00 27.1 179.4 0.0 -0.6 -12 1 2 10000 11 34 30 11 36 30 --- 17 46 00 27.1 179.9 0.0 -0.1 108 R 1 8400 11 36 30 W109 17 46 00 30.2 179.3 0.0 -0.7 -12 1 2 8400 11 36 30 11 37 30 --- 17 47 01 30.2 179.5 0.0 -0.5 48 R 1 7600 11 37 30 I1746-321 17 47 01 27.1 180.1 0.0 0.1 -12 1 2 7600 11 37 30 11 40 00 --- 17 49 31 27.1 180.7 0.1 0.7 138 R 1 5600 11 40 00 GC441 17 49 31 29.8 182.1 0.1 2.1 -11 1 2 5600 11 40 00 11 41 00 --- 17 50 31 29.8 182.4 0.2 2.3 49 R 1 4800 11 41 00 I1746-321 17 50 31 27.1 181.0 0.1 1.0 -11 1 2 4800 11 41 00 11 43 00 --- 17 52 32 27.1 181.4 0.1 1.5 109 R 1 3200 Schedule for VLBA_FD (Code Fd ) Page 4 IGR J1746-321 ToO UP: D => Below limits; H => Below horizon mask. blank => Up. Early: Seconds between end of slew and start. Dwell: On source seconds. Tapes: Drive, Index, Start footage / Direction, Head Group, End footage. TPStart: Tape motion start time. Frequencies are LO sum (band edge). Automatic tape allocation specified. Tape positions are just estimates. ---------------------------------------------------------------------------------------- Start UT Source Start / Stop Early Tapes TPStart Stop UT LST EL AZ HA UP ParA Dwell (see above) ---------------------------------------------------------------------------------------- --- Tue 8 Apr 2003 Day 98 --- 11 43 00 GC441 17 52 32 29.8 182.9 0.2 2.8 -11 1 2 3200 11 43 00 11 44 00 --- 17 53 32 29.8 183.1 0.2 3.1 49 R 1 2400 11 44 00 W56 17 53 32 31.0 181.9 0.1 1.9 -8 1 2 2400 11 44 00 11 45 00 --- 17 54 32 31.0 182.2 0.1 2.1 52 R 1 1600 11 47 00 J1733-1304 17 56 32 45.9 188.2 0.4 7.2 84 1 2 1600 11 47 00 11 48 00 --- 17 57 32 45.9 188.5 0.4 7.5 60 R 1 800 11 48 00 I1746-321 17 57 32 27.1 182.6 0.2 2.7 -44 1 3 800 11 48 00 11 50 00 --- 17 59 33 27.1 183.1 0.2 3.2 76 F 1 800 11 50 00 W109 17 59 33 30.2 182.7 0.2 2.6 -12 1 3 800 11 50 00 11 51 00 --- 18 00 33 30.2 182.9 0.2 2.9 48 F 1 1600 11 51 00 I1746-321 18 00 33 27.0 183.3 0.2 3.4 -12 1 3 1600 11 51 00 11 53 00 --- 18 02 33 27.0 183.8 0.3 3.9 108 F 1 3200 11 53 00 W109 18 02 33 30.1 183.4 0.2 3.4 -12 1 3 3200 11 53 00 11 54 00 --- 18 03 33 30.1 183.7 0.2 3.6 48 F 1 4000 11 54 00 I1746-321 18 03 33 27.0 184.1 0.3 4.1 -12 1 3 4000 11 54 00 11 56 00 --- 18 05 34 27.0 184.5 0.3 4.6 108 F 1 5600 11 56 00 W109 18 05 34 30.1 184.2 0.3 4.1 -12 1 3 5600 11 56 00 11 57 00 --- 18 06 34 30.1 184.4 0.3 4.4 48 F 1 6400 11 57 00 I1746-321 18 06 34 26.9 184.8 0.3 4.9 -12 1 3 6400 11 57 00 11 59 00 --- 18 08 34 26.9 185.2 0.4 5.3 108 F 1 8000 11 59 00 W109 18 08 34 30.1 184.9 0.3 4.9 -12 1 3 8000 11 59 00 12 00 00 --- 18 09 34 30.0 185.2 0.3 5.1 48 F 1 8800 12 00 00 I1746-321 18 09 34 26.9 185.5 0.4 5.6 -12 1 3 8800 12 00 00 12 02 30 --- 18 12 05 26.8 186.1 0.4 6.2 138 F 1 10800 12 02 30 GC441 18 12 05 29.4 187.7 0.5 7.6 -11 1 3 10800 12 02 30 12 03 30 --- 18 13 05 29.4 188.0 0.5 7.9 49 F 1 11600 12 03 30 I1746-321 18 13 05 26.8 186.3 0.4 6.4 -11 1 3 11600 12 03 30 12 05 30 --- 18 15 05 26.8 186.8 0.5 6.9 109 F 1 13200 Schedule for VLBA_FD (Code Fd ) Page 5 IGR J1746-321 ToO UP: D => Below limits; H => Below horizon mask. blank => Up. Early: Seconds between end of slew and start. Dwell: On source seconds. Tapes: Drive, Index, Start footage / Direction, Head Group, End footage. TPStart: Tape motion start time. Frequencies are LO sum (band edge). Automatic tape allocation specified. Tape positions are just estimates. ---------------------------------------------------------------------------------------- Start UT Source Start / Stop Early Tapes TPStart Stop UT LST EL AZ HA UP ParA Dwell (see above) ---------------------------------------------------------------------------------------- --- Tue 8 Apr 2003 Day 98 --- 12 05 30 GC441 18 15 05 29.3 188.5 0.6 8.4 -11 1 3 13200 12 05 30 12 06 30 --- 18 16 05 29.3 188.7 0.6 8.6 49 F 1 14000 12 06 30 W56 18 16 05 30.6 187.7 0.5 7.5 -9 1 3 14000 12 06 30 12 07 30 --- 18 17 06 30.6 187.9 0.5 7.7 51 F 1 14800 12 09 30 J1733-1304 18 19 06 44.9 195.9 0.8 14.0 85 1 3 14800 12 09 30 12 10 30 --- 18 20 06 44.9 196.2 0.8 14.3 60 F 1 15600 12 10 30 I1746-321 18 20 06 26.6 188.0 0.6 8.1 -42 1 3 15600 12 10 30 12 12 30 --- 18 22 06 26.6 188.4 0.6 8.6 78 F 1 17200 12 12 30 W109 18 22 06 29.7 188.3 0.6 8.2 -12 1 4 17200 12 12 30 12 13 30 --- 18 23 07 29.7 188.6 0.6 8.5 48 R 1 16400 12 13 30 I1746-321 18 23 07 26.5 188.7 0.6 8.8 -12 1 4 16400 12 13 30 12 15 30 --- 18 25 07 26.5 189.1 0.6 9.3 108 R 1 14800 12 15 30 W109 18 25 07 29.6 189.1 0.6 8.9 -12 1 4 14800 12 15 30 12 16 30 --- 18 26 07 29.6 189.3 0.6 9.2 48 R 1 14000 12 16 30 I1746-321 18 26 07 26.4 189.4 0.7 9.5 -12 1 4 14000 12 16 30 12 18 30 --- 18 28 07 26.4 189.8 0.7 10.0 108 R 1 12400 12 18 30 W109 18 28 07 29.5 189.8 0.7 9.7 -12 1 4 12400 12 18 30 12 19 30 --- 18 29 08 29.5 190.1 0.7 9.9 48 R 1 11600 12 19 30 I1746-321 18 29 08 26.3 190.1 0.7 10.2 -12 1 4 11600 12 19 30 12 21 30 --- 18 31 08 26.2 190.5 0.7 10.7 108 R 1 10000 12 21 30 W109 18 31 08 29.4 190.6 0.7 10.4 -12 1 4 10000 12 21 30 12 22 30 --- 18 32 08 29.4 190.8 0.7 10.7 48 R 1 9200 12 22 30 I1746-321 18 32 08 26.2 190.8 0.8 10.9 -12 1 4 9200 12 22 30 12 25 00 --- 18 34 38 26.1 191.3 0.8 11.5 138 R 1 7200 12 25 00 GC441 18 34 38 28.5 193.3 0.9 13.1 -11 1 4 7200 12 25 00 12 26 00 --- 18 35 39 28.5 193.5 0.9 13.3 49 R 1 6400 12 26 00 I1746-321 18 35 39 26.1 191.6 0.8 11.8 -11 1 4 6400 12 26 00 12 28 00 --- 18 37 39 26.0 192.0 0.9 12.2 109 R 1 4800 Schedule for VLBA_FD (Code Fd ) Page 6 IGR J1746-321 ToO UP: D => Below limits; H => Below horizon mask. blank => Up. Early: Seconds between end of slew and start. Dwell: On source seconds. Tapes: Drive, Index, Start footage / Direction, Head Group, End footage. TPStart: Tape motion start time. Frequencies are LO sum (band edge). Automatic tape allocation specified. Tape positions are just estimates. ---------------------------------------------------------------------------------------- Start UT Source Start / Stop Early Tapes TPStart Stop UT LST EL AZ HA UP ParA Dwell (see above) ---------------------------------------------------------------------------------------- --- Tue 8 Apr 2003 Day 98 --- 12 28 00 GC441 18 37 39 28.4 194.0 0.9 13.8 -11 1 4 4800 12 28 00 12 29 00 --- 18 38 39 28.3 194.2 1.0 14.1 49 R 1 4000 12 29 00 W56 18 38 39 29.7 193.3 0.9 13.0 -9 1 4 4000 12 29 00 12 30 00 --- 18 39 39 29.7 193.6 0.9 13.3 51 R 1 3200 12 32 00 J1733-1304 18 41 40 43.3 203.2 1.1 20.3 87 1 4 3200 12 32 00 12 33 00 --- 18 42 40 43.2 203.5 1.2 20.6 60 R 1 2400 12 33 00 I1746-321 18 42 40 25.7 193.2 0.9 13.4 -41 1 4 2400 12 33 00 12 35 00 --- 18 44 40 25.6 193.6 1.0 13.9 79 R 1 800 12 35 00 W109 18 44 40 28.8 193.9 0.9 13.7 -12 1 4 800 12 35 00 12 36 00 --- 18 45 40 28.7 194.1 0.9 13.9 48 R 1 0 12 36 00 I1746-321 18 45 40 25.6 193.9 1.0 14.1 -12 1 5 0 12 36 00 12 38 00 --- 18 47 41 25.5 194.3 1.0 14.6 108 F 1 1600 12 38 00 W109 18 47 41 28.6 194.6 1.0 14.4 -12 1 5 1600 12 38 00 12 39 00 --- 18 48 41 28.6 194.8 1.0 14.6 48 F 1 2400 12 39 00 I1746-321 18 48 41 25.4 194.5 1.0 14.8 -12 1 5 2400 12 39 00 12 41 00 --- 18 50 41 25.3 195.0 1.1 15.3 108 F 1 4000 12 41 00 W109 18 50 41 28.5 195.3 1.0 15.1 -12 1 5 4000 12 41 00 12 42 00 --- 18 51 41 28.4 195.6 1.0 15.3 48 F 1 4800 12 42 00 I1746-321 18 51 41 25.3 195.2 1.1 15.5 -12 1 5 4800 12 42 00 12 44 00 --- 18 53 42 25.1 195.7 1.1 16.0 108 F 1 6400 12 44 00 W109 18 53 42 28.3 196.0 1.1 15.8 -12 1 5 6400 12 44 00 12 45 00 --- 18 54 42 28.2 196.3 1.1 16.0 48 F 1 7200 12 45 00 I1746-321 18 54 42 25.1 195.9 1.1 16.2 -12 1 5 7200 12 45 00 12 47 00 --- 18 56 42 25.0 196.4 1.2 16.6 108 F 1 8800 12 47 00 W109 18 56 42 28.1 196.8 1.1 16.5 -12 1 5 8800 12 47 00 12 48 00 --- 18 57 42 28.0 197.0 1.1 16.7 48 F 1 9600 12 48 00 I1746-321 18 57 42 24.9 196.6 1.2 16.9 -12 1 5 9600 12 48 00 12 50 00 --- 18 59 43 24.8 197.0 1.2 17.3 108 F 1 11200 Schedule for VLBA_FD (Code Fd ) Page 7 IGR J1746-321 ToO UP: D => Below limits; H => Below horizon mask. blank => Up. Early: Seconds between end of slew and start. Dwell: On source seconds. Tapes: Drive, Index, Start footage / Direction, Head Group, End footage. TPStart: Tape motion start time. Frequencies are LO sum (band edge). Automatic tape allocation specified. Tape positions are just estimates. ---------------------------------------------------------------------------------------- Start UT Source Start / Stop Early Tapes TPStart Stop UT LST EL AZ HA UP ParA Dwell (see above) ---------------------------------------------------------------------------------------- --- Tue 8 Apr 2003 Day 98 --- 12 50 00 W109 18 59 43 27.9 197.5 1.2 17.2 -12 1 5 11200 12 50 00 12 51 00 --- 19 00 43 27.8 197.7 1.2 17.4 48 F 1 12000 12 51 00 I1746-321 19 00 43 24.7 197.2 1.2 17.5 -12 1 5 12000 12 51 00 12 53 30 --- 19 03 13 24.6 197.8 1.3 18.1 138 F 1 14000 12 53 30 GC441 19 03 13 26.8 200.0 1.4 19.8 -10 1 5 14000 12 53 30 12 54 30 --- 19 04 13 26.7 200.2 1.4 20.0 50 F 1 14800 12 54 30 I1746-321 19 04 13 24.5 198.0 1.3 18.3 -10 1 5 14800 12 54 30 12 56 30 --- 19 06 14 24.4 198.5 1.3 18.8 110 F 1 16400 12 56 30 GC441 19 06 14 26.5 200.7 1.4 20.4 -10 1 5 16400 12 56 30 12 57 30 --- 19 07 14 26.5 200.9 1.4 20.7 50 F 1 17200 12 57 30 I1746-321 19 07 14 24.3 198.7 1.3 19.0 -10 1 6 17200 12 57 30 12 59 00 --- 19 08 44 24.2 199.0 1.4 19.4 80 R 1 16000 12 59 00 W56 19 08 44 27.8 200.6 1.4 20.1 -13 1 6 16000 12 59 00 13 00 00 --- 19 09 44 27.7 200.8 1.4 20.3 47 R 1 15200 SETUP FILE INFORMATION: NOTE: If DOPPLER, FREQ, or BW were used, see the individual scans for the final BBC settings. Setup file: /users/cwalker/sched/setups/v2cm-256-8-2.set Matches group v2cm_d3 in /users/cwalker/sched/catalogs/freq.dat Fourth 2cm filter Setup group: 1 Station: VLBA Total bit rate: 256 Format: VLBA1:2 Bits per sample: 2 Sample rate: 16.000 Number of channels: 8 Passes/head pos: 1 Speedup factor: 1.00 Tape speeds: Low density - 266.660 ips, High density - 160.00 ips Time per pass for 17600 ft, High density tapes is: 00:22:00 1st LO= 14600.00 14600.00 14600.00 14600.00 14600.00 14600.00 14600.00 14600.00 Net 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 = B D B D B D B D VLBA FE= omit 2cm omit 2cm VLBA Synth= 14.6 10.9 10.9 The following frequency sets based on this setup were used. Frequency Set: 1 Setup file default. Used pcal sets: 1 LO sum= 15349.49 15349.49 15357.49 15357.49 15365.49 15365.49 15373.49 15373.49 BBC fr= 749.49 749.49 757.49 757.49 765.49 765.49 773.49 773.49 Bandwd= 8.000 8.000 8.000 8.000 8.000 8.000 8.000 8.000 The following pulse cal sets were used with this setup: Pulse cal detection set: 1 PCAL = 1MHZ PCALXB1= S1 S3 S5 S7 S1 S3 S5 S7 PCALXB2= S2 S4 S6 S8 S2 S4 S6 S8 PCALFR1= 510 510 510 510 6510 6510 6510 6510 PCALFR2= 510 510 510 510 6510 6510 6510 6510 Track assignments are: track1= 2, 10, 18, 26, 3, 11, 19, 27 barrel=roll_auto SOURCE LIST -- IGR J1746-321 ToO Catalog positions marked with *. Precession of date coordinates is based on stop time of first scan. Names used in schedule marked with *. Short names used in VLA and SNAP files marked with +. Observation date used in B1950/J2000 coordinate conversion (PRECDATE): 1979.900 No adjustments are made for rates (DRA, DDEC). Source Source position (RA/Dec) (B1950) (J2000) (Date) * I1746-321 17 42 59.799246 * 17 46 15.607000 17 46 27.723285 -32 12 53.51182 *-32 14 00.70000 -32 14 06.16971 From catalog imbedded in main SCHED input file. * GC441 17 37 43.113166 * 17 40 54.524900 17 41 06.394475 -29 28 19.93553 *-29 29 50.29000 -29 29 58.12492 From catalog imbedded in main SCHED input file. * J1733-1304 17 30 13.535186 * 17 33 02.705784 17 33 13.246165 -13 02 45.83985 *-13 04 49.54833 -13 05 04.87816 From catalog imbedded in main SCHED input file. * W109 17 45 34.736305 * 17 48 45.684100 17 48 57.483620 -29 06 43.28585 *-29 07 39.37400 -29 07 45.19707 From catalog imbedded in main SCHED input file. * W56 17 42 42.769582 * 17 45 52.494900 17 46 04.233452 -28 19 17.62858 *-28 20 26.27000 -28 20 33.14011 From catalog imbedded in main SCHED input file. 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) I1746-321 110.9 GC441 112.3 J1733-1304 114.5 W109 110.6 W56 111.2 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