1. Selfcal for phase:
Task: selfcal vis = xmiriad050218_230_rx0.lsb select = source(ti*,3c111*,ga*,ce*,17*) interval = .5 refant = 6 offset = line = chan,1,1,3072
2. Start bee:
Task: bee vis = miriad050128_230_rx0.lsb device = /xs
Here are the interactive instruction for using the fitting, plotting and editting functions that are supported in bee:
Number of points= 130 Enter antenna to display : 1 Number of points= 130 AVAILABLE COMMANDS ARE: 1P Fit axis offset 2P 2-parameter fit [sets B3 = -cotan(LAT)*B1] 3P 3-parameter fit to phase differences 4P 4-parameter fit; no 2PI discontinuities ! 5P 5-parameter fit includes axis offset AM Plot amplitudes versus time ED Edit to new baseline etc. EX Exit BEE and write antpos file FI Seach for best fit baseline GR Plot vs. HA, sin(DEC), elevation, or focus IN Get the Gains for another antenna LI List antenna positions and current fit. PH Plot phase versus time TE Edit data to test fitting programs TF Tpower and Tair fit to phase TH Plot airtemp versus time TP Plot tpower versus phase and fit slope. WA Write ANTPOS file. WG Write gains into the output gains file.
3. Plotting Phase:
One can use one of the commands, such as PH for plotting phase vs. time. Here is an exmaple:
command=ph Plot phase versus time and fit. SELECT SOURCES Type source numbers separated by commas <cr> means finished; <a> means all sources 1 titan 2 3c111 3 ganymede 4 ceres 5 1743-038 SOURCES: a in plot window type CURSOR OPTIONS: A restore deleted points B set bottom to cursor position C Connect cursor positions D move phase point down by 2pi E end manipulations on plot F show instrumental phase fit G fit gains to tpower plot H Hanning smooth fitted curve I Identify the sources J Join the plotted points K superpose temperature plot L set left to cursor position M plot more sources N set new limits and replot O superpose tpower plot P replot on printer Q position fit R set right to cursor position S replot T set top to cursor position U move phase point up by 2pi V delete point(s) W write the source labels at top of plot X average and rms of plotted points 0 - 8 order of polynomial fit + unwrap phase
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4. Baseline Fitting:
bee also supports least square fitting to the phase difference for new antenna positions:
command=in % choose new antenna
Enter antenna to display :1 % choose anetnna 1
Number of points= 845
command=4p % 4parameter fits
4-PARAMETER FIT
Fit antenna positions and constant phase offset
SELECT SOURCES
Type source numbers separated by commas
<cr> means finished; <a> means all sources
1 titan 2 3c111 3 ganymede 4 ceres
5 1743-038
SOURCES: a % average all source
>>>> report of the results from the baseline fit to antenna 1 <<<<
4 parameter fit, sigma: 0.0502
initial baseline 14.80856 -213.06612 -72.84222 0.00000 0.00000
new baseline 14.81041 -213.06482 -72.84171 -2.24603 0.00000
delta baseline 0.00185 0.00130 0.00050 -2.24603 0.00000
uncertainties 0.000017 0.000006 0.000011 0.008770
covariance matrix
24.1681 0.1636 0.1474 0.9680
0.0169 14.0156 -0.3741 0.0788
-0.0087 0.0220 9.6160 0.2996
-0.0259 -0.0021 -0.0080 29.5466
command=fi
Step size for bx/by/bz ( 0.0020) :0.0001
# of steps in 1-D ( 40.) :15
Step size for antmiss ( 0.0020) :0.0001
# of steps (1=nofit) ( 1.) :1
BEE FIT DATA--starting with:
bx = 14.8086 by = -213.0661 bz =-72.8422 antmiss = 0.0000 chisq = 3.09
bx = 14.8079 by = -213.0668 bz =-72.8429 antmiss = 0.0000 chisq = 1.63
bx = 14.8079 by = -213.0668 bz =-72.8428 antmiss = 0.0000 chisq = 1.63
bx = 14.8079 by = -213.0668 bz =-72.8427 antmiss = 0.0000 chisq = 1.63
bx = 14.8079 by = -213.0668 bz =-72.8424 antmiss = 0.0000 chisq = 1.62
bx = 14.8079 by = -213.0668 bz =-72.8423 antmiss = 0.0000 chisq = 1.62
bx = 14.8079 by = -213.0668 bz =-72.8422 antmiss = 0.0000 chisq = 1.53
bx = 14.8079 by = -213.0668 bz =-72.8421 antmiss = 0.0000 chisq = 1.45
bx = 14.8079 by = -213.0668 bz =-72.8420 antmiss = 0.0000 chisq = 1.44
bx = 14.8079 by = -213.0668 bz =-72.8419 antmiss = 0.0000 chisq = 1.44
bx = 14.8079 by = -213.0668 bz =-72.8416 antmiss = 0.0000 chisq = 1.39
bx = 14.8079 by = -213.0667 bz =-72.8426 antmiss = 0.0000 chisq = 1.32
bx = 14.8079 by = -213.0667 bz =-72.8425 antmiss = 0.0000 chisq = 1.32
bx = 14.8079 by = -213.0667 bz =-72.8416 antmiss = 0.0000 chisq = 1.19
bx = 14.8079 by = -213.0666 bz =-72.8416 antmiss = 0.0000 chisq = 1.10
bx = 14.8079 by = -213.0666 bz =-72.8415 antmiss = 0.0000 chisq = 1.10
bx = 14.8079 by = -213.0664 bz =-72.8419 antmiss = 0.0000 chisq = 1.02
bx = 14.8079 by = -213.0663 bz =-72.8417 antmiss = 0.0000 chisq = 1.01
bx = 14.8079 by = -213.0662 bz =-72.8418 antmiss = 0.0000 chisq = 1.01
bx = 14.8079 by = -213.0662 bz =-72.8417 antmiss = 0.0000 chisq = 1.01
bx = 14.8079 by = -213.0662 bz =-72.8416 antmiss = 0.0000 chisq = 1.01
bx = 14.8079 by = -213.0662 bz =-72.8415 antmiss = 0.0000 chisq = 1.01
command=in
Enter antenna to display :2 % for antenna 2
Number of points= 846
command=4p
4-PARAMETER FIT
Fit antenna positions and constant phase offset
SELECT SOURCES
Type source numbers separated by commas
<cr> means finished; <a> means all sources
1 titan 2 3c111 3 ganymede 4 ceres
5 1743-038
SOURCES: a
4 parameter fit, sigma: 0.0131
initial baseline -19.01948 -63.32772 52.06702 0.00000 0.00000
new baseline -19.01964 -63.32768 52.06705 0.60843 0.00000
delta baseline -0.00015 0.00005 0.00004 0.60843 0.00000
uncertainties 0.000005 0.000002 0.000003 0.002456
covariance matrix
23.9466 0.2085 0.1593 0.9686
0.0940 13.4426 -0.4154 0.1348
0.0298 -0.0778 9.5842 0.3195
0.0621 0.0086 0.0205 29.0861
command=fi
Step size for bx/by/bz ( 0.0020) :0.0001
# of steps in 1-D ( 40.) :15
Step size for antmiss ( 0.0020) :0.0001
# of steps (1=nofit) ( 1.) :1
BEE FIT DATA--starting with:
bx = -19.0195 by = -63.3277 bz = 52.0670 antmiss = 0.0000 chisq = 0.10
bx = -19.0202 by = -63.3278 bz = 52.0663 antmiss = 0.0000 chisq = 0.10
bx = -19.0202 by = -63.3277 bz = 52.0663 antmiss = 0.0000 chisq = 0.10
bx = -19.0202 by = -63.3276 bz = 52.0663 antmiss = 0.0000 chisq = 0.10
One can go through the least square fitting for all the antennas
to obtain corrections for positions.
The gains derived from amplitude and phase fits are write to the gains file and the new antenna position can be written out to a text file. Here is an exmaple:
command=EX The gains derived from amplitude and phase fits using the ED command are written at this time. The gains are written into the output gains file. The default output is the input uvdata file. OK to write the gains ?y Number of solution intervals: 875
5. Write New Antenna Positions:
Enter filename for antenna positions: antpos.new
#Fitted antenna positions - Mon Mar 21 16:25:18 2005
14.8079 -213.0662 -72.8415
-19.0202 -63.3276 52.0663
-1.6940 -83.9048 4.2696
17.4370 -66.9718 -49.5145
-59.7692 -198.6647 100.2966
0.0000 0.0000 0.0000
0.0000 0.0000 0.0000
0.0000 0.0000 0.0000