[alma-config]Re: [mmaimcal]Memo 428
mel wright 456
wright at astron.berkeley.edu
Wed Jul 3 16:18:45 EDT 2002
1) Since time is rather short, here is the table of the mosaicing tests so
far.
It will take me some time to analyse all the data,
but I see that the mosaicing results so far seem to favor the Gaussian config
2 over
the NS extended config for dec 60. From dec = +45 to -60 config 2 and 5
give about
the same image fidelity. The NS extended config has a rounder beam at dec
+30 to +60,
the Gaussian config has a rounder beam from dec +15 to -60.
2) As I see it the biggest problem for ALMA is the missing short spacings, and
I'd rather
spend any ``savings'' on a few 6-7 m antennas.
cheers,
Melvyn
Stephane Guilloteau wrote:
> Be carefull
>
> - we cannot (yet) simply assume the ACA will be build
> - however, we (astronomers) cannot continue dreaming to build whatever
> we wish for ALMA.
>
> We have a budget constraint, and within the current uncertainties, saving 1
> M$ or so on 25 pads
> would be more than welcome. I would rather re-affect that 1M$ to a better
> calibration system. In that
> area, we have some unfunded items which would be useful, such as an
> automated FTS and its associated
> software. This would be useful for most projects, while the 25 pads for an
> elongated N/S compact configuration
> are at best only useful for 5 % of the projects.
>
> Using the inner "spiral" pads and some re-weighting scheme is not optimal
> when considering fixed configurations, but if we add up the overhead time
> and associated losses due to reconfiguring to such special configuration,
> this becomes less obvious.
>
> Given the imaging results shown by Mel Wright, I would strongly argue
> AGAINST the added complexity
> of the "elongated compact" configuration.
>
> And remember: the configuration design IS URGENT.
>
> The current feeling of most members in the ALMA Management Advisory
> Committee is that we will need some descoping of the project, and these
> people certainly have a lot of expertise on large projects. Having to
> descope a receiver band would be disastrous. So we have to be careful in all
> items which have a small influence of the overall performance of ALMA, but
> result in some quantifiable cost savings..
>
> Stephane
>
> ----- Original Message -----
> From: "Al Wootten" <awootten at NRAO.EDU>
> To: <alma-config at NRAO.EDU>; <guillote at iram.fr>
> Sent: Wednesday, June 26, 2002 4:49 PM
> Subject: [alma-config]Re: [mmaimcal]Memo 428
>
> > Configurees:
> >
> > I think that we should assume nothing about the ACA at the moment.
> > We have a bilateral project, and the ACC is anxious lest the funding
> > parties become confused over the bilateral nature of it. We need a
> > configuration design before we will know if the ACA will exist, an
> > unfortunate fact of life. Thus, the form of the ACA must be determined in
> > such a way as to blend best into the ALMA configuration.
> >
> > Al
> >
> > John Conway writes:
> > >
> > > > The problem of the number of compact configurations is significantly
> > > > simpler than it used to be: we no longer need to worry so hard about
> > > > getting lots of short projected spacings at all declinations with the
> > > > addition of the ACA (which, by the way, is costing a bit more than
> those
> > > > 25 extra pads would have cost).
> > > >
> > >
> > > This is a major issue though. Are we really assuming 100% certainty
> > > that ACA will be built given its not in the bilateral baseline plan? I
> > > think that we have to ensure that the array of 12m dishes has
> reasonable
> > > very short baseline coverage. Mark is making the argument I guess
> > > that with ACA we don't need to have many configurations for the 12m
> > > antennas so that for ALL declinations we can observe such that in
> > > projection the antennas are just going into shadowing (so we are
> sensitive
> > > to 0-3m baselines), but surely in any case projection helps you mainly
> in
> > > the filling in the short baselines the v direction; in test uv
> > > coverages I have done as expected the shortest centre-to-centre
> baseline
> > > along the u-axis stays around the antenna collision seperation
> distance
> > > of 15m. In conclusion using projection to fill in short spacings is
> > > only a partial solution at best and really to do a good job we
> > > need the ACA (..which is why this is top of our wish list)
> >
> > _______________________________________________
> > Alma-config mailing list
> > Alma-config at listmgr.cv.nrao.edu
> > http://listmgr.cv.nrao.edu/mailman/listinfo/alma-config
> >
>
> _______________________________________________
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> Alma-config at listmgr.cv.nrao.edu
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-------------- next part --------------
--- ALMA Mosaicing (Cas A model) ---
config = config1
dec = -15
scale = 0.04
harange = -1,1,.013 hours
select = -shadow(12)
freq = 230
nchan = 1
imsize = 129
region = arcsec,box(20,-20,-20,20)
--- TIMING ---
START: Wed Jul 3 10:57:34 PDT 2002
Generate uv-data. Tsys=40K, bandwidth=8 GHz
UVGEN: Wed Jul 3 10:57:46 PDT 2002
Scale model size. from pixel 0.4 to 0.04 arcsec
Make model images for each pointing center
Make model uv-data using VLA image of Cas A as a model (the model has the VLA primary beam)
UVMODEL: Wed Jul 3 11:00:29 PDT 2002 add the model to the noisy sampled uv-data
INVERT: Wed Jul 3 11:00:48 PDT 2002
Make single dish image and beam Wed Jul 3 11:00:48 PDT 2002
Single dish FWHM = 24 arcsec at 230 GHz
Joint deconvolution of interferometer and single dish data
MOSMEM: Wed Jul 3 11:03:39 PDT 2002
convolve the model by the beam and subtract from the deconvolved image
regrid the convolved model to the deconvolved image template
FINISH: Wed Jul 3 11:03:45 PDT 2002
--- RESULTS ---
1) Tests: Allowing shadowed data. Increase niters and decrease rmsfac -> better deconvolution.
region = arcsec,box(15,-15,-15,15)
Config DEC HA[hrs] Beam[arcsec] scale Model_Flux,Peak Image_Flux,Peak Residual:Rms,Max,Min[Jy]
config1 -30 -1,1,.013 1.70 1.69 0.03 731.580 14.249 756.762 14.230 0.134 0.335 -0.273
config1 -30 -1,1,.013 1.70 1.69 0.03 731.580 14.249 671.239 13.853 0.153 0.688 -0.506
niters=30 rmsfac=40000
config1 -30 -1,1,.013 1.70 1.69 0.03 731.580 14.249 710.101 14.035 0.076 0.334 -0.247
niters=30 rmsfac=20000
config1 -30 -1,1,.013 1.70 1.69 0.03 731.580 14.249 732.112 14.137 0.038 0.156 -0.118
niters=50 rmsfac=10000
config1 30 -1,1,.013 2.82 1.70 0.03 731.534 21.011 743.387 20.877 0.053 0.226 -0.174
niters=50 rmsfac=10000
increase thermal noise; decrease BW by factor 10000 from 8 GHz to 0.8 MHz. rmsfac=100
config1 30 -1,1,.013 2.82 1.70 0.03 731.534 21.011 743.375 20.876 0.053 0.226 -0.174
mosmem niters=60 rmsfac=10000
Config DEC HA[hrs] Beam[arcsec] scale Model_Flux,Peak Image_Flux,Peak Residual:Rms,Max,Min[Jy]
config1 60 -1,1,.013 11.15 1.92 0.03 725.056 55.881 705.903 54.279 0.871 1.385 -6.162
config2 60 -1,1,.013 8.18 1.42 0.03 728.763 36.903 721.969 36.180 0.323 0.818 -2.503
config5 60 -1,1,.013 6.62 1.80 0.03 730.006 40.256 726.673 39.246 0.261 0.796 -1.033
config1 45 -1,1,.013 4.39 1.73 0.03 731.215 29.579 732.936 29.015 0.109 0.421 -0.283
config2 45 -1,1,.013 3.30 1.30 0.03 731.511 18.838 735.968 18.784 0.041 0.198 -0.101
config5 45 -1,1,.013 2.32 1.70 0.03 731.563 18.137 737.243 17.940 0.032 0.143 -0.183
config1 30 -1,1,.013 2.82 1.70 0.03 731.534 21.011 743.387 20.877 0.053 0.226 -0.174
config2 30 -1,1,.013 2.11 1.28 0.03 731.602 13.290 748.073 13.340 0.023 0.084 -0.066
config5 30 -1,1,.013 1.70 1.44 0.03 731.583 12.573 748.930 12.504 0.027 0.094 -0.073
config1 0 -1,1,.013 1.83 1.70 0.03 731.577 15.148 742.309 14.960 0.037 0.148 -0.099
config2 0 -1,1,.013 1.38 1.28 0.03 731.615 9.554 730.887 9.507 0.029 0.136 -0.084
config5 0 -1,1,.013 1.73 0.94 0.03 731.586 8.998 728.474 8.968 0.031 0.153 -0.112
config1 -30 -1,1,.013 1.70 1.69 0.03 731.580 14.249 732.112 14.137 0.038 0.156 -0.118
config2 -30 -1,1,.013 1.28 1.27 0.03 731.616 8.937 717.376 8.857 0.041 0.194 -0.141
config5 -30 -1,1,.013 1.74 0.87 0.03 731.586 8.465 718.574 8.383 0.041 0.194 -0.147
config1 -45 -1,1,.013 1.81 1.70 0.03 731.577 15.021 740.702 14.824 0.037 0.149 -0.101
config2 -45 -1,1,.013 1.36 1.28 0.03 731.615 9.444 728.697 9.412 0.030 0.136 -0.092
config5 -45 -1,1,.013 1.73 0.93 0.03 731.586 8.917 729.577 8.887 0.032 0.155 -0.112
config1 -60 -1,1,.013 2.09 1.70 0.03 731.571 16.763 750.780 16.643 0.047 0.162 -0.134
config2 -60 -1,1,.013 1.58 1.28 0.03 731.612 10.635 748.798 10.644 0.023 0.082 -0.054
config5 -60 -1,1,.013 1.71 1.08 0.03 731.586 10.011 742.419 10.048 0.025 0.108 -0.078
undersampled uv-data. 10x Nyquist sample interval
Config DEC HA[hrs] Beam[arcsec] scale Model_Flux,Peak Image_Flux,Peak Residual:Rms,Max,Min[Jy]
config1 30 -1,1,.13 2.81 1.72 0.03 731.533 21.146 742.640 20.983 0.052 0.235 -0.168
config2 30 -1,1,.13 2.11 1.30 0.03 731.601 13.469 747.382 13.422 0.022 0.090 -0.053
config5 30 -1,1,.13 1.71 1.44 0.03 731.582 12.632 748.320 12.578 0.027 0.107 -0.074
config1 -30 -1,1,.13 1.71 1.69 0.03 731.579 14.317 732.402 14.217 0.038 0.166 -0.111
config2 -30 -1,1,.13 1.29 1.27 0.03 731.616 8.998 719.207 8.909 0.040 0.186 -0.139
config5 -30 -1,1,.13 1.75 0.87 0.03 731.585 8.504 720.171 8.431 0.041 0.191 -0.141
undersampled uv-data. mosmem niters=250 rmsfac=1000
Config DEC HA[hrs] Beam[arcsec] scale Model_Flux,Peak Image_Flux,Peak Residual:Rms,Max,Min[Jy]
config1 30 -1,1,.13 2.81 1.72 0.03 731.533 21.146 732.496 20.908 0.041 0.199 -0.229
config2 30 -1,1,.13 2.11 1.30 0.03 731.601 13.469 733.538 13.360 0.013 0.085 -0.087
config5 30 -1,1,.13 1.71 1.44 0.03 731.582 12.632 734.376 12.524 0.015 0.086 -0.117
config1 -30 -1,1,.13 1.71 1.69 0.03 731.579 14.317 738.871 14.237 0.023 0.107 -0.114
config2 -30 -1,1,.13 1.29 1.27 0.03 731.616 8.998 743.678 8.985 0.010 0.039 -0.070
config5 -30 -1,1,.13 1.75 0.87 0.03 731.585 8.504 742.770 8.489 0.010 0.057 -0.074
mosmem niters=250 rmsfac=1000
Config DEC HA[hrs] Beam[arcsec] scale Model_Flux,Peak Image_Flux,Peak Residual:Rms,Max,Min[Jy]
config1 30 -1,1,.013 2.82 1.70 0.03 731.534 21.011 732.834 20.802 0.042 0.192 -0.224
config2 30 -1,1,.013 2.11 1.28 0.03 731.602 13.290 733.839 13.280 0.014 0.081 -0.085
config5 30 -1,1,.013 1.70 1.44 0.03 731.583 12.573 734.500 12.449 0.015 0.070 -0.115
config1 -30 -1,1,.013 1.70 1.69 0.03 731.580 14.249 738.976 14.157 0.023 0.086 -0.114
config2 -30 -1,1,.013 1.28 1.27 0.03 731.616 8.937 743.615 8.936 0.010 0.036 -0.068
config5 -30 -1,1,.013 1.74 0.87 0.03 731.586 8.465 742.638 8.445 0.010 0.057 -0.075
increase pointing sampling to hex19 and region=arcsec,box(20,-20,-20,20)
Config DEC HA[hrs] Beam[arcsec] scale Model_Flux,Peak Image_Flux,Peak Residual:Rms,Max,Min[Jy]
config1 30 -1,1,.013 2.81 1.71 0.04 731.602 13.302 733.563 13.236 0.012 0.064 -0.066
config2 30 -1,1,.013 2.11 1.29 0.04 731.630 8.305 739.296 8.290 0.006 0.023 -0.036
config5 30 -1,1,.013 1.70 1.44 0.04 731.619 7.798 742.174 7.799 0.009 0.032 -0.068
config1 -30 -1,1,.013 1.70 1.69 0.04 731.617 8.892 737.607 8.843 0.017 0.050 -0.064
config2 -30 -1,1,.013 1.28 1.27 0.04 731.638 5.463 750.609 5.483 0.012 0.033 -0.032
config5 -30 -1,1,.013 1.75 0.87 0.04 731.621 5.199 746.940 5.208 0.012 0.029 -0.037
2) Production run. reject all shadowed data. select=-shadow(12). source size ~ 32''. mosaic hex19
Config DEC HA[hrs] Beam[arcsec] scale Model_Flux,Peak Image_Flux,Peak Residual:Rms,Max,Min[Jy]
config1 60 -1,1,.013 17.81 1.86 0.04 719.180 44.845 650.777 40.750 0.964 1.634 -5.567
config2 60 -1,1,.013 6.38 0.97 0.04 731.133 14.460 752.351 14.290 0.130 0.426 -0.231
config5 60 -1,1,.013 9.22 1.50 0.04 729.838 27.473 736.907 26.716 0.335 2.763 -0.603
config1 45 -1,1,.013 5.69 1.58 0.04 731.300 21.042 764.473 20.294 0.577 1.381 -1.044
config2 45 -1,1,.013 2.62 1.01 0.04 731.637 7.869 750.441 7.781 0.024 0.070 -0.047
config5 45 -1,1,.013 2.20 1.56 0.04 731.618 10.163 753.110 10.135 0.024 0.072 -0.089
config1 30 -1,1,.013 2.53 1.60 0.04 731.611 11.594 758.991 11.654 0.036 0.115 -0.175
config2 30 -1,1,.013 1.89 1.10 0.04 731.642 6.599 759.106 6.598 0.018 0.057 -0.046
config5 30 -1,1,.013 1.61 1.38 0.04 731.624 7.178 751.334 7.172 0.016 0.047 -0.055
config1 15 -1,1,.013 2.17 1.68 0.04 731.613 10.735 745.882 10.672 0.018 0.057 -0.075
config2 15 -1,1,.013 1.61 1.25 0.04 731.637 6.503 759.015 6.540 0.014 0.043 -0.054
config5 15 -1,1,.013 1.70 1.11 0.04 731.622 6.261 750.938 6.230 0.011 0.035 -0.038
config1 0 -1,1,.013 1.83 1.70 0.04 731.615 9.480 740.503 9.409 0.014 0.055 -0.053
config2 0 -1,1,.013 1.38 1.28 0.04 731.638 5.854 756.046 5.865 0.011 0.036 -0.027
config5 0 -1,1,.013 1.73 0.94 0.04 731.621 5.508 753.526 5.568 0.012 0.037 -0.036
config1 -15 -1,1,.013 1.70 1.70 0.04 731.617 8.934 739.640 8.893 0.017 0.051 -0.067
config2 -15 -1,1,.013 1.28 1.28 0.04 731.638 5.499 753.943 5.520 0.013 0.037 -0.033
config5 -15 -1,1,.013 1.75 0.88 0.04 731.621 5.251 750.087 5.231 0.013 0.030 -0.034
config1 -30 -1,1,.013 1.70 1.69 0.04 731.617 8.892 737.607 8.843 0.017 0.050 -0.064
config2 -30 -1,1,.013 1.28 1.27 0.04 731.638 5.463 750.609 5.483 0.012 0.033 -0.032
config5 -30 -1,1,.013 1.75 0.87 0.04 731.621 5.199 746.940 5.208 0.012 0.029 -0.037
config1 -45 -1,1,.013 1.81 1.70 0.04 731.616 9.397 739.712 9.314 0.014 0.054 -0.051
config2 -45 -1,1,.013 1.36 1.28 0.04 731.638 5.784 755.492 5.807 0.011 0.036 -0.026
config5 -45 -1,1,.013 1.73 0.93 0.04 731.621 5.456 750.656 5.503 0.011 0.032 -0.032
config1 -60 -1,1,.013 2.10 1.69 0.04 731.613 10.517 745.380 10.450 0.017 0.056 -0.071
config2 -60 -1,1,.013 1.57 1.26 0.04 731.637 6.418 758.285 6.460 0.013 0.041 -0.049
config5 -60 -1,1,.013 1.70 1.09 0.04 731.622 6.164 750.832 6.158 0.012 0.036 -0.037
3) Production run. reject all shadowed data. select=-shadow(12). source size ~ 24''. mosaic hex7
Config DEC HA[hrs] Beam[arcsec] scale Model_Flux,Peak Image_Flux,Peak Residual:Rms,Max,Min[Jy]
config1 60 -1,1,.013 18.70 1.85 0.03 682.588 65.262 650.154 58.472 2.427 5.586 -13.143
config2 60 -1,1,.013 6.72 0.96 0.03 729.994 23.299 742.212 23.094 0.188 0.623 -0.877
config5 60 -1,1,.013 9.56 1.46 0.03 727.370 40.785 721.586 39.697 0.450 1.054 -3.060
config1 45 -1,1,.013 5.68 1.57 0.03 730.649 32.978 748.685 31.777 0.516 2.328 -0.854
config2 45 -1,1,.013 2.63 1.00 0.03 731.595 12.584 743.585 12.607 0.026 0.128 -0.079
config5 45 -1,1,.013 2.21 1.55 0.03 731.580 16.199 740.118 16.030 0.030 0.137 -0.158
config1 30 -1,1,.013 2.56 1.59 0.03 731.561 18.526 738.228 18.349 0.043 0.200 -0.174
config2 30 -1,1,.013 1.90 1.09 0.03 731.618 10.645 742.375 10.654 0.015 0.071 -0.055
config5 30 -1,1,.013 1.60 1.39 0.03 731.593 11.631 740.116 11.501 0.017 0.073 -0.092
config1 15 -1,1,.013 2.17 1.67 0.03 731.571 16.995 736.266 16.807 0.029 0.124 -0.170
config2 15 -1,1,.013 1.61 1.25 0.03 731.614 10.569 739.395 10.574 0.011 0.054 -0.059
config5 15 -1,1,.013 1.69 1.11 0.03 731.588 10.141 740.318 10.128 0.013 0.067 -0.093
config1 0 -1,1,.013 1.83 1.70 0.03 731.577 15.148 739.518 14.930 0.026 0.104 -0.144
config2 0 -1,1,.013 1.38 1.28 0.03 731.615 9.554 742.587 9.534 0.011 0.042 -0.055
config5 0 -1,1,.013 1.73 0.94 0.03 731.586 8.998 741.706 9.003 0.011 0.057 -0.071
config1 -15 -1,1,.013 1.70 1.70 0.03 731.579 14.314 739.775 14.215 0.024 0.089 -0.138
config2 -15 -1,1,.013 1.28 1.28 0.03 731.616 8.993 742.178 8.970 0.009 0.035 -0.051
config5 -15 -1,1,.013 1.74 0.87 0.03 731.586 8.465 743.286 8.476 0.010 0.055 -0.083
config1 -30 -1,1,.013 1.70 1.69 0.03 731.580 14.249 738.976 14.157 0.023 0.086 -0.114
config2 -30 -1,1,.013 1.28 1.27 0.03 731.616 8.937 743.615 8.936 0.010 0.036 -0.068
config5 -30 -1,1,.013 1.74 0.87 0.03 731.586 8.465 742.638 8.445 0.010 0.057 -0.075
config1 -45 -1,1,.013 1.81 1.70 0.03 731.577 15.021 739.629 14.802 0.025 0.100 -0.144
config2 -45 -1,1,.013 1.36 1.28 0.03 731.615 9.444 742.670 9.447 0.011 0.038 -0.052
config5 -45 -1,1,.013 1.73 0.93 0.03 731.586 8.917 743.291 8.916 0.011 0.057 -0.086
config1 -60 -1,1,.013 2.10 1.68 0.03 731.573 16.661 736.486 16.486 0.028 0.124 -0.167
config2 -60 -1,1,.013 1.58 1.26 0.03 731.614 10.489 739.452 10.461 0.010 0.049 -0.060
config5 -60 -1,1,.013 1.70 1.09 0.03 731.587 10.038 741.859 10.017 0.013 0.059 -0.116
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