COVER INFORMATION Station: VLBA_OV (Code Ov ) Experiment: 3mm observing with autopeak Exp. Code: BJ045D Schedule Version: 1.00 Processed by SCHED version: 6.05 June 2006 PI: Bill Junor Address: ISR-1, Space & Atmospheric Sciences MS D466, LANL, P.O. Box 1663 Los Alamos, New Mexico, 87545 U.S.A. Phone: 505 667 0788 EMAIL: bjunor@lanl.gov Fax: 505 665 7395 Phone during observation: 505 699 7692 Observing mode: 3mm 512-8-2 Notes: Will use reference pointing. COVER LETTER: BJ045 SUMMARY: This project needs about 40 hours times 28 baselines to meet the sensitivity requirements. This time can be accumulated in many separated sessions but MK should appear in all sessions. Each session should be a full track with all antennas to set the calibration and ensure full uv coverage. Tropospheric weather is the problem for these 3mm observations. 3C274 is mostly a night-time object now. 2 tapes per station. -------------------------------------------------------------------- Here is the official dynamic scheduling sheet: ================================================================ Preferred Dynamic Contraints. Alter [defaults] as desired. ================================================================ Equipment constraints: Stations. Below each station code, the "o" indicates an [optional] station that is to be used if it is available. Change "o" to "r" if the station is required or change "o" to "n" if the station is not to be used. SC HN NL FD LA PT KP OV BR MK n o o o o o o o n r Minimum number of stations [7]: May we swap PT for a single VLA antenna? [no] Consult http://www.aoc.nrao.edu/~gtaylor/y1gotcha.html to decide. If you adopt the default, then both PT and VLA1 must be in the stations list in the keyin file. Bands and polarizations. Below each band code, insert "R" if the righthand polarization is to be used, "L" if the lefthand polarization is to be used, "d" if dual polarizations are to be used, or "o" if the band is in your setups but scheduling should not be constrained by its availability. 90cm 50cm 20cm 13cm 6cm 4cm 2cm 1cm 7mm 3mm d Weather constraints: [appropriate for bands marked "L", "R", or "d" above and for at least the minimum number of stations] Best tropospheric conditions for 3mm. Date constraints: Preferred date(s), usually a series start [none]: Excluded dates plus reason [none]: Preferred interval between segments in days [none]: Special conditions (e.g., a series with different spacings in time) [See the comments at the top.]: Must include MK Schedule for VLBA_OV (Code Ov ) Page 2 3mm observing with autopeak 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. For disks, the footages are really the GBytes TPStart: Tape motion start time. Frequencies are LO sum (band edge). SYNC: Time correlator is expected to sync up. 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) SYNC ---------------------------------------------------------------------------------------- --- Sat 26 Aug 2006 Day 238 --- Next scan frequencies: 43115.99 43115.99 43215.99 43215.99 Next BBC frequencies: 715.99 715.99 815.99 815.99 Next scan bandwidths: 16.00 16.00 16.00 16.00 17 23 12 3C273 07 49 22 17.1 100.8 -4.7 -51.5 0 1 1 0 Stopped 17 28 11 --- 07 54 22 18.0 101.6 -4.6 -51.3 299 S 1 0 Next scan frequencies: 86212.49 86212.49 86228.49 86228.49 86244.49 86244.49 86260.49 86260.49 Next BBC frequencies: 712.49 712.49 728.49 728.49 744.49 744.49 760.49 760.49 Next scan bandwidths: 16.00 16.00 16.00 16.00 16.00 16.00 16.00 16.00 17 28 41 3C273 07 54 52 18.1 101.7 -4.6 -51.3 25 1 1 0 17 28 41 17 34 40 --- 08 00 52 19.3 102.7 -4.5 -51.0 359 F 1 4787 17 28 49 17 36 40 3C274 08 02 52 25.6 93.8 -4.5 -54.4 101 1 1 4787 17 36 40 17 47 38 --- 08 13 52 27.8 95.6 -4.3 -54.2 658 F 1 13563 17 36 48 17 48 08 3C274 08 14 22 27.9 95.6 -4.3 -54.2 25 1 2 13563 17 48 08 17 59 06 --- 08 25 22 30.1 97.4 -4.1 -53.9 658 R 1 12861 17 48 16 18 01 06 3C274 08 27 22 30.5 97.8 -4.1 -53.9 113 1 2 12861 18 01 06 18 12 04 --- 08 38 22 32.6 99.6 -3.9 -53.5 658 R 1 4085 18 01 14 Next scan frequencies: 43115.99 43115.99 43215.99 43215.99 Next BBC frequencies: 715.99 715.99 815.99 815.99 Next scan bandwidths: 16.00 16.00 16.00 16.00 18 12 34 3C273 08 38 52 26.6 109.3 -3.8 -48.8 12 1 2 4085 Stopped 18 17 33 --- 08 43 52 27.5 110.2 -3.8 -48.4 299 S 1 4085 Schedule for VLBA_OV (Code Ov ) Page 3 3mm observing with autopeak 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. For disks, the footages are really the GBytes TPStart: Tape motion start time. Frequencies are LO sum (band edge). SYNC: Time correlator is expected to sync up. 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) SYNC ---------------------------------------------------------------------------------------- --- Sat 26 Aug 2006 Day 238 --- Next scan frequencies: 86212.49 86212.49 86228.49 86228.49 86244.49 86244.49 86260.49 86260.49 Next BBC frequencies: 712.49 712.49 728.49 728.49 744.49 744.49 760.49 760.49 Next scan bandwidths: 16.00 16.00 16.00 16.00 16.00 16.00 16.00 16.00 18 18 03 3C273 08 44 22 27.6 110.3 -3.8 -48.3 25 1 3 4085 18 18 03 18 24 02 --- 08 50 22 28.7 111.5 -3.7 -47.9 359 F 1 702 18 18 11 18 26 02 3C274 08 52 22 35.4 102.1 -3.6 -52.8 100 1 3 702 18 26 02 18 37 00 --- 09 03 22 37.5 104.2 -3.5 -52.2 658 F 1 9478 18 26 10 18 37 30 3C274 09 03 52 37.6 104.2 -3.5 -52.2 25 1 4 9478 18 37 30 18 48 28 --- 09 14 52 39.7 106.4 -3.3 -51.4 658 R 1 16946 18 37 38 18 50 28 3C274 09 16 52 40.1 106.8 -3.2 -51.3 113 1 4 16946 18 50 28 19 01 26 --- 09 27 52 42.2 109.0 -3.1 -50.4 658 R 1 8170 18 50 36 Next scan frequencies: 43115.99 43115.99 43215.99 43215.99 Next BBC frequencies: 715.99 715.99 815.99 815.99 Next scan bandwidths: 16.00 16.00 16.00 16.00 19 01 56 3C273 09 28 22 35.5 119.2 -3.0 -44.0 11 1 4 8170 Stopped 19 06 55 --- 09 33 22 36.4 120.4 -2.9 -43.4 299 S 1 8170 Next scan frequencies: 86212.49 86212.49 86228.49 86228.49 86244.49 86244.49 86260.49 86260.49 Next BBC frequencies: 712.49 712.49 728.49 728.49 744.49 744.49 760.49 760.49 Next scan bandwidths: 16.00 16.00 16.00 16.00 16.00 16.00 16.00 16.00 19 07 25 3C273 09 33 52 36.5 120.5 -2.9 -43.4 25 1 4 8170 19 07 25 19 13 24 --- 09 39 52 37.5 121.8 -2.8 -42.6 359 R 1 3383 19 07 33 19 15 24 3C274 09 41 52 44.8 112.1 -2.8 -49.1 99 1 5 3383 19 15 24 19 26 22 --- 09 52 52 46.8 114.6 -2.6 -47.8 658 F 1 5392 19 15 32 Schedule for VLBA_OV (Code Ov ) Page 4 3mm observing with autopeak 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. For disks, the footages are really the GBytes TPStart: Tape motion start time. Frequencies are LO sum (band edge). SYNC: Time correlator is expected to sync up. 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) SYNC ---------------------------------------------------------------------------------------- --- Sat 26 Aug 2006 Day 238 --- 19 26 52 3C274 09 53 22 46.9 114.7 -2.6 -47.8 25 1 5 5392 19 26 52 19 37 50 --- 10 04 22 48.9 117.5 -2.4 -46.3 658 F 1 14168 19 27 00 19 39 50 3C274 10 06 22 49.2 118.0 -2.4 -46.0 113 1 6 14168 19 39 50 19 50 48 --- 10 17 22 51.1 120.9 -2.2 -44.4 658 R 1 12256 19 39 58 Next scan frequencies: 43115.99 43115.99 43215.99 43215.99 Next BBC frequencies: 715.99 715.99 815.99 815.99 Next scan bandwidths: 16.00 16.00 16.00 16.00 19 51 18 3C273 10 17 52 43.6 131.5 -2.2 -36.7 9 1 6 12256 Stopped 19 56 17 --- 10 22 52 44.3 132.9 -2.1 -35.7 299 S 1 12256 Next scan frequencies: 86212.49 86212.49 86228.49 86228.49 86244.49 86244.49 86260.49 86260.49 Next BBC frequencies: 712.49 712.49 728.49 728.49 744.49 744.49 760.49 760.49 Next scan bandwidths: 16.00 16.00 16.00 16.00 16.00 16.00 16.00 16.00 19 56 47 3C273 10 23 22 44.4 133.0 -2.1 -35.6 25 1 6 12256 19 56 47 20 02 46 --- 10 29 22 45.3 134.7 -2.0 -34.5 359 R 1 7469 19 56 55 20 04 45 3C274 10 31 22 53.5 125.0 -2.0 -41.9 97 1 7 7469 20 04 45 20 15 44 --- 10 42 22 55.2 128.5 -1.8 -39.6 658 F 1 1307 20 04 53 20 16 14 3C274 10 42 52 55.3 128.7 -1.8 -39.5 25 1 7 1307 20 16 14 20 27 12 --- 10 53 52 57.0 132.5 -1.6 -37.0 658 F 1 10083 20 16 22 20 29 11 3C274 10 55 52 57.2 133.2 -1.6 -36.5 114 1 8 10083 20 29 11 20 40 10 --- 11 06 52 58.8 137.3 -1.4 -33.5 658 R 1 16341 20 29 19 Next scan frequencies: 43115.99 43115.99 43215.99 43215.99 Next BBC frequencies: 715.99 715.99 815.99 815.99 Next scan bandwidths: 16.00 16.00 16.00 16.00 20 40 40 3C273 11 07 22 50.0 146.9 -1.4 -25.8 6 1 8 16341 Stopped 20 45 39 --- 11 12 22 50.6 148.7 -1.3 -24.4 299 S 1 16341 Schedule for VLBA_OV (Code Ov ) Page 5 3mm observing with autopeak 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. For disks, the footages are really the GBytes TPStart: Tape motion start time. Frequencies are LO sum (band edge). SYNC: Time correlator is expected to sync up. 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) SYNC ---------------------------------------------------------------------------------------- --- Sat 26 Aug 2006 Day 238 --- Next scan frequencies: 86212.49 86212.49 86228.49 86228.49 86244.49 86244.49 86260.49 86260.49 Next BBC frequencies: 712.49 712.49 728.49 728.49 744.49 744.49 760.49 760.49 Next scan bandwidths: 16.00 16.00 16.00 16.00 16.00 16.00 16.00 16.00 20 46 09 3C273 11 12 52 50.6 148.9 -1.3 -24.3 25 1 8 16341 20 46 09 20 52 08 --- 11 18 52 51.2 151.1 -1.2 -22.7 359 R 1 11554 20 46 17 20 54 07 3C274 11 20 52 60.6 143.1 -1.2 -29.3 95 1 8 11554 20 54 07 21 05 06 --- 11 31 52 61.8 148.1 -1.0 -25.5 658 R 1 2778 20 54 15 21 05 35 3C274 11 32 22 61.9 148.3 -1.0 -25.4 25 1 9 2778 21 05 35 21 16 34 --- 11 43 22 62.9 153.6 -0.8 -21.2 658 F 1 5998 21 05 43 21 18 33 3C274 11 45 22 63.1 154.6 -0.8 -20.4 113 1 9 5998 21 18 33 21 29 32 --- 11 56 22 63.9 160.4 -0.6 -15.9 658 F 1 14774 21 18 41 Next scan frequencies: 43115.99 43115.99 43215.99 43215.99 Next BBC frequencies: 715.99 715.99 815.99 815.99 Next scan bandwidths: 16.00 16.00 16.00 16.00 21 30 01 3C273 11 56 52 54.0 166.1 -0.5 -11.1 4 1 9 14774 Stopped 21 35 01 --- 12 01 52 54.2 168.2 -0.5 -9.4 299 S 1 14774 Next scan frequencies: 86212.49 86212.49 86228.49 86228.49 86244.49 86244.49 86260.49 86260.49 Next BBC frequencies: 712.49 712.49 728.49 728.49 744.49 744.49 760.49 760.49 Next scan bandwidths: 16.00 16.00 16.00 16.00 16.00 16.00 16.00 16.00 21 35 31 3C273 12 02 22 54.2 168.4 -0.5 -9.2 25 1 10 14774 21 35 31 21 41 30 --- 12 08 22 54.5 170.9 -0.4 -7.2 359 R 1 15639 21 35 39 21 43 29 3C274 12 10 22 64.7 168.1 -0.3 -9.7 93 1 10 15639 21 43 29 21 54 27 --- 12 21 22 65.0 174.3 -0.2 -4.6 658 R 1 6863 21 43 37 Schedule for VLBA_OV (Code Ov ) Page 6 3mm observing with autopeak 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. For disks, the footages are really the GBytes TPStart: Tape motion start time. Frequencies are LO sum (band edge). SYNC: Time correlator is expected to sync up. 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) SYNC ---------------------------------------------------------------------------------------- --- Sat 26 Aug 2006 Day 238 --- 21 54 57 3C274 12 21 52 65.0 174.6 -0.2 -4.4 25 1 11 6863 21 54 57 22 05 56 --- 12 32 52 65.1 181.0 0.0 0.8 658 F 1 1913 21 55 05 22 07 55 3C274 12 34 52 65.1 182.2 0.1 1.8 113 1 11 1913 22 07 55 22 18 53 --- 12 45 52 64.9 188.5 0.2 6.9 658 F 1 10689 22 08 03 Next scan frequencies: 43115.99 43115.99 43215.99 43215.99 Next BBC frequencies: 715.99 715.99 815.99 815.99 Next scan bandwidths: 16.00 16.00 16.00 16.00 22 19 23 3C273 12 46 22 54.6 187.3 0.3 5.8 3 1 11 10689 Stopped 22 24 22 --- 12 51 22 54.4 189.4 0.4 7.5 299 S 1 10689 Next scan frequencies: 86212.49 86212.49 86228.49 86228.49 86244.49 86244.49 86260.49 86260.49 Next BBC frequencies: 712.49 712.49 728.49 728.49 744.49 744.49 760.49 760.49 Next scan bandwidths: 16.00 16.00 16.00 16.00 16.00 16.00 16.00 16.00 22 24 52 3C273 12 51 52 54.4 189.7 0.4 7.7 25 1 11 10689 22 24 52 22 30 51 --- 12 57 52 54.2 192.2 0.5 9.7 359 F 1 15476 22 25 00 22 32 51 3C274 12 59 52 64.3 196.4 0.5 13.3 93 1 12 15476 22 32 51 22 43 49 --- 13 10 52 63.6 202.2 0.7 18.0 658 R 1 10948 22 32 59 22 44 19 3C274 13 11 22 63.5 202.5 0.7 18.2 25 1 12 10948 22 44 19 22 55 17 --- 13 22 22 62.6 208.1 0.9 22.6 658 R 1 2172 22 44 27 22 57 17 3C274 13 24 22 62.4 209.0 0.9 23.3 113 1 13 2172 22 57 17 23 08 15 --- 13 35 22 61.3 214.2 1.1 27.3 658 F 1 6604 22 57 25 Next scan frequencies: 43115.99 43115.99 43215.99 43215.99 Next BBC frequencies: 715.99 715.99 815.99 815.99 Next scan bandwidths: 16.00 16.00 16.00 16.00 23 08 45 3C273 13 35 52 51.6 207.4 1.1 21.5 5 1 13 6604 Stopped 23 13 44 --- 13 40 52 51.1 209.2 1.2 22.9 299 S 1 6604 Schedule for VLBA_OV (Code Ov ) Page 7 3mm observing with autopeak 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. For disks, the footages are really the GBytes TPStart: Tape motion start time. Frequencies are LO sum (band edge). SYNC: Time correlator is expected to sync up. 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) SYNC ---------------------------------------------------------------------------------------- --- Sat 26 Aug 2006 Day 238 --- Next scan frequencies: 86212.49 86212.49 86228.49 86228.49 86244.49 86244.49 86260.49 86260.49 Next BBC frequencies: 712.49 712.49 728.49 728.49 744.49 744.49 760.49 760.49 Next scan bandwidths: 16.00 16.00 16.00 16.00 16.00 16.00 16.00 16.00 23 14 14 3C273 13 41 22 51.1 209.4 1.2 23.0 25 1 13 6604 23 14 14 23 20 13 --- 13 47 22 50.5 211.6 1.3 24.7 359 F 1 11391 23 14 22 23 22 13 3C274 13 49 22 59.6 220.2 1.3 31.8 95 1 14 11391 23 22 13 23 33 11 --- 14 00 22 58.1 224.6 1.5 34.9 658 R 1 15034 23 22 21 23 33 41 3C274 14 00 52 58.0 224.8 1.5 35.0 25 1 14 15034 23 33 41 23 44 39 --- 14 11 52 56.4 228.8 1.7 37.8 658 R 1 6258 23 33 49 SETUP FILE INFORMATION: NOTE: If DOPPLER, FREQ, or BW were used, see the individual scans for the final BBC settings. Setup file: /home/filehost/cwalker/sched/setups/pt7mm.set Matches group v7mm_c8 in /home/filehost/cwalker/sched/catalogs/freq.dat Setup group: 15 Station: VLBA_OV Total bit rate: 256 Format: NONE Bits per sample: 2 Sample rate: 32.000 Number of channels: 4 Setup not used for recording data. 1st LO= 42400.00 42400.00 42400.00 42400.00 Net SB= U U U U Pol. = RCP LCP RCP LCP BBC = 1 2 3 4 BBC SB= U U U U IF = A C A C VLBA FE= 7mm omit 7mm omit VLBA Synth= 15.4 7.6 11.6 The following frequency sets based on this setup were used. Frequency Set: 7 Setup file default. Used pcal sets: 1 LO sum= 43115.99 43115.99 43215.99 43215.99 BBC fr= 715.99 715.99 815.99 815.99 Bandwd= 16.000 16.000 16.000 16.000 The following pulse cal sets were used with this setup: Pulse cal detection set: 1 PCAL = OFF PCALXB1= S1 S2 S3 S4 OFF OFF OFF OFF PCALXB2= M1 M2 M3 M4 OFF OFF OFF OFF PCALFR1= 0 0 0 0 0 0 0 0 PCALFR2= 0 0 0 0 0 0 0 0 Setup file: v3mm-512-8-2.set Matches group v3mm_ff in /home/filehost/cwalker/sched/catalogs/freq.dat Setup group: 7 Station: VLBA_OV Total bit rate: 512 Format: VLBA1:4 Bits per sample: 2 Sample rate: 32.000 Number of channels: 8 Passes/head pos: 1 Speedup factor: 1.00 Tape used at high density at 160.000 ips. Time per pass is 22.00 minutes. Two tape drives will be used. Required by this setup. 1st LO= 85500.00 85500.00 85500.00 85500.00 85500.00 85500.00 85500.00 85500.00 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 3mm omit 3mm VLBA Synth= 12.9 15.4 12.1 The following frequency sets based on this setup were used. Frequency Set: 14 Setup file default. Used pcal sets: 2 LO sum= 86212.49 86212.49 86228.49 86228.49 86244.49 86244.49 86260.49 86260.49 BBC fr= 712.49 712.49 728.49 728.49 744.49 744.49 760.49 760.49 Bandwd= 16.000 16.000 16.000 16.000 16.000 16.000 16.000 16.000 The following pulse cal sets were used with this setup: Pulse cal detection set: 2 PCAL = OFF PCALXB1= S1 S2 S3 S4 S5 S6 S7 S8 PCALXB2= M1 M2 M3 M4 M5 M6 M7 M8 PCALFR1= 0 0 0 0 0 0 0 0 PCALFR2= 0 0 0 0 0 0 0 0 Track assignments are: track1= 2, 18, 3, 19, 66, 82, 67, 83 barrel=roll_auto SOURCE LIST -- 3mm observing with autopeak 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). Scan hours are for recording scans only. Baseline hours are only counted for scans above horizon at both ends. Source Source position (RA/Dec) Error (B1950) (J2000) (Date) (mas) J1229+0203 12 26 33.245836 * 12 29 06.699732 12 29 26.217370 0.30 1226+023 02 19 43.30565 * 02 03 08.59815 02 01 02.05249 0.20 * 3C273 /home/filehost/cwalker/sched/catalogs/sources.vlba 3C273B VLBA Calib Survey - GSFC sols. - created L.Petrov 2005f_astro J1229+02 0.798 scan hours, 20.245 baseline hours above horizon. J1230+1223 12 28 17.569279 * 12 30 49.423381 12 31 08.814772 0.31 1228+126 12 40 01.74901 * 12 23 28.04383 12 21 23.37736 0.20 * 3C274 /home/filehost/cwalker/sched/catalogs/sources.vlba J1230+12 VLBA Calib Survey - GSFC sols. - created L.Petrov 2005f_astro 4.205 scan hours, 110.065 baseline hours above horizon. 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) 3C273 32.8 3C274 31.8 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