IRAS16293 Band9 - Calibration for CASA 3.3: Difference between revisions
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Spectral windows are also marked with numbers from 0 24, with 0 containing WVR information. Spws 17, 19, 21, and 23 contain the sience data (TDM mode). The CO (6-5) line emission is contained in spw 21. Spw 18, 20, 22, and 24 contain channel averages of the data in spectral windows 17, 19, 21, 23, respectively. These spws will not be used for the offline data reduction. All the remaining spw that appear in the section of sources, and that do not appear in the Spectral Windows are related to WVR measurements for each antenna, so you will not need them for the calibration. Spws 9, 11, 13, and 15 are associated with tsys measurements, and we will apply these information to the science spws later. | Spectral windows are also marked with numbers from 0 24, with 0 containing WVR information. Spws 17, 19, 21, and 23 contain the sience data (TDM mode). The CO (6-5) line emission is contained in spw 21. Spw 18, 20, 22, and 24 contain channel averages of the data in spectral windows 17, 19, 21, 23, respectively. These spws will not be used for the offline data reduction. All the remaining spw that appear in the section of sources, and that do not appear in the Spectral Windows are related to WVR measurements for each antenna, so you will not need them for the calibration. Spws 9, 11, 13, and 15 are associated with tsys measurements, and we will apply these information to the science spws later. | ||
==Visualization and exploration of Tsys and WVR tables== | |||
Next we need to check the plotting for tsys and wvr tables to make sure whether they have issues that might affect their application to the data. Whenever we see an odd behavior in the tables we need to flag the corresponding sience data to prevent wrong results in the calibration steps. The next command will plot the tsys in the next way: it will produce many plots, each one of them will show an antenna, with the four spw that tsys covers, for all the targets, and with different colors for different times, so you can trace the behavior for tsys with time, among others. | |||
Note that in spw 19 and 21, the overlap with the tsys spw (11 and 13) is not set correctly. This is due to an error in the frequencies for the tsys when the observations were done. You do not have to worry about this, since any issue coming from the error have already been handled. Note, however that the portions of the spectra that do not have tsys information cannot be used. This does not represent a problem, since that part corresponds to the edge of the baseband. Also note that the CO (6-5) line is not affected by this. | |||
<source lang="python"> | <source lang="python"> | ||
Revision as of 20:59, 21 May 2012
- This script assumes that you have downloaded IRAS16293_Band9_UnCalibratedMSAndTablesForReduction.tgz from IRAS16293Band9#Download the data
- Details of the ALMA observations are provided at IRAS16293Band9
- This portion of the guide covers calibration of the raw visibility data. To skip to the imaging portion of the guide, see: IRAS16293_Band9_-_Imaging.
Overview
This part of the casa guide will guide you through the basic inspection of the data, paying special attention to detect data that needs to be flagged. The guide goes later to the process of full calibration to split the data at the end.
The general procedure in this guide follows the other ALMA CASA guides: NGC3256Band3 and AntennaeBand7.
Unpack the Data
Once you have downloaded the IRAS16293_Band9_UnCalibratedMSandTablesForReduction.tgz, unpack the file in a terminal outside CASA using
tar -xvzf IRAS16293_Band9_UnCalibratedMSandTablesForReduction.tgz
cd IRAS16293_Band9_UnCalibratedMSandTablesForReduction
You have a number of files with extensions ".ms", which are CASA measurement set (MS) files. You will also see files containing system temperature (Tsys), water vapor radiometer (WVR), and antenna position information.
To start CASA type
casapy
Be sure that you are using the right version indicated for this guide.
Initial Inspection
The first step we will do through all the calibration process is to define an array with the uid's that corresponds to the datasets names. This will allow to make the calibration of the four datasets one after another, using an for-loop inside python. We will then calibrate the data individually and concatenate them at the end, before proceeding with the imaging part.
Note that if you exit CASA and want to continue with the calibration using these arrays, you will have to re-issue the command again to make it available for the current CASA execution.
To start, and give an example of this process, we will create txt format files for the output of the listobs task, which will give us useful information about the observations.
# In CASA
rawdata=['uid___A002_X3d4118_X39b.ms','uid___A002_X3d55cb_X575.ms',
'uid___A002_X3d55cb_Xb50.ms','uid___A002_X3d55cb_X90c.ms']
# We create the text files for listobs for each dataset
for data in rawdata:
listobs(vis=data,listfile=data+'.listobs')
Note that after cutting and pasting a for-loop you often have to press return several times to make the command executes. The output will be sent to the CASA logger. Next there is an example of a useful part of the output that the first listobs of the previews command produces.
Fields: 11 ID Code Name RA Decl Epoch SrcId nVis 0 none 1924-292 19:24:51.05600 -29.14.30.1280 J2000 0 169125 1 none nrao530 ph 17:33:02.72400 -13.04.49.4860 J2000 1 289170 2 none Juno 16:25:31.63031 -05.49.08.9209 J2000 2 82890 3 none 1625-254 16:25:46.98000 -25.27.38.3300 J2000 3 276480 4 none IRAS16293-2422-a 16:32:22.99200 -24.28.36.0000 J2000 4 132450 5 none IRAS16293-2422-a 16:32:22.47925 -24.28.36.0000 J2000 4 99915 6 none IRAS16293-2422-a 16:32:22.73563 -24.28.36.0000 J2000 4 99960 7 none IRAS16293-2422-a 16:32:22.73563 -24.28.32.5000 J2000 4 99915 8 none IRAS16293-2422-a 16:32:22.47925 -24.28.29.0000 J2000 4 99945 9 none IRAS16293-2422-a 16:32:22.73563 -24.28.29.0000 J2000 4 99945 10 none IRAS16293-2422-a 16:32:22.99200 -24.28.29.0000 J2000 4 99915 (nVis = Total number of time/baseline visibilities per field) Spectral Windows: (25 unique spectral windows and 2 unique polarization setups) SpwID #Chans Frame Ch1(MHz) ChanWid(kHz) TotBW(kHz) Corrs 0 4 TOPO 184550 1500000 7500000 I 1 128 TOPO 231257.813 15625 2000000 XX YY 2 1 TOPO 232234.375 1796875 1796875 XX YY 3 128 TOPO 229257.813 15625 2000000 XX YY 4 1 TOPO 230234.375 1796875 1796875 XX YY 5 128 TOPO 217242.188 15625 2000000 XX YY 6 1 TOPO 216234.375 1796875 1796875 XX YY 7 128 TOPO 215242.188 15625 2000000 XX YY 8 1 TOPO 214234.375 1796875 1796875 XX YY 9 128 TOPO 703257.813 15625 2000000 XX YY 10 1 TOPO 704234.375 1796875 1796875 XX YY 11 128 TOPO 692492.188 15625 2000000 XX YY 12 1 TOPO 691484.375 1796875 1796875 XX YY 13 128 TOPO 690492.188 15625 2000000 XX YY 14 1 TOPO 689484.375 1796875 1796875 XX YY 15 128 TOPO 688492.188 15625 2000000 XX YY 16 1 TOPO 687484.375 1796875 1796875 XX YY 17 3840 TOPO 703312.744 488.28125 1875000 XX YY 18 1 TOPO 704249.756 1875000 1875000 XX YY 19 3840 TOPO 692237.256 488.28125 1875000 XX YY 20 1 TOPO 691299.756 1875000 1875000 XX YY 21 3840 TOPO 690437.256 488.28125 1875000 XX YY 22 1 TOPO 689499.756 1875000 1875000 XX YY 23 3840 TOPO 688437.256 488.28125 1875000 XX YY 24 1 TOPO 687499.756 1875000 1875000 XX YY Sources: 176 ID Name SpwId RestFreq(MHz) SysVel(km/s) 0 1924-292 0 - - 0 1924-292 25 - - 0 1924-292 26 - - 0 1924-292 27 - - 0 1924-292 28 - - 0 1924-292 29 - - 0 1924-292 30 - - 0 1924-292 31 - - 0 1924-292 32 - - 0 1924-292 33 - - 0 1924-292 34 - - 0 1924-292 35 - - 0 1924-292 36 - - 0 1924-292 37 - - 0 1924-292 38 - - 0 1924-292 39 - - 0 1924-292 1 - - 0 1924-292 2 - - 0 1924-292 3 - - 0 1924-292 4 - - 0 1924-292 5 - - 0 1924-292 6 - - 0 1924-292 7 - - 0 1924-292 8 - - 0 1924-292 9 - - 0 1924-292 10 - - 0 1924-292 11 - - 0 1924-292 12 - - 0 1924-292 13 - - 0 1924-292 14 - - 0 1924-292 15 - - 0 1924-292 16 - - 0 1924-292 17 - - 0 1924-292 18 - - 0 1924-292 19 - - 0 1924-292 20 - - 0 1924-292 21 - - 0 1924-292 22 - - 0 1924-292 23 - - 0 1924-292 24 - - 1 nrao530 ph 0 - - 1 nrao530 ph 25 - - 1 nrao530 ph 26 - - 1 nrao530 ph 27 - - 1 nrao530 ph 28 - - 1 nrao530 ph 29 - - 1 nrao530 ph 30 - - 1 nrao530 ph 31 - - 1 nrao530 ph 32 - - 1 nrao530 ph 33 - - 1 nrao530 ph 34 - - 1 nrao530 ph 35 - - 1 nrao530 ph 36 - - 1 nrao530 ph 37 - - 1 nrao530 ph 38 - - 1 nrao530 ph 39 - - 1 nrao530 ph 1 - - 1 nrao530 ph 2 - - 1 nrao530 ph 3 - - 1 nrao530 ph 4 - - 1 nrao530 ph 5 - - 1 nrao530 ph 6 - - 1 nrao530 ph 7 - - 1 nrao530 ph 8 - - 2 Juno 0 - - 2 Juno 25 - - 2 Juno 26 - - 2 Juno 27 - - 2 Juno 28 - - 2 Juno 29 - - 2 Juno 30 - - 2 Juno 31 - - 2 Juno 32 - - 2 Juno 33 - - 2 Juno 34 - - 2 Juno 35 - - 2 Juno 36 - - 2 Juno 37 - - 2 Juno 38 - - 2 Juno 39 - - 1 Juno 9 - - 1 Juno 10 - - 1 Juno 11 - - 1 Juno 12 - - 1 Juno 13 - - 1 Juno 14 - - 1 Juno 15 - - 1 Juno 16 - - 1 Juno 17 - - 1 Juno 18 - - 1 Juno 19 - - 1 Juno 20 - - 1 Juno 21 - - 1 Juno 22 - - 1 Juno 23 - - 1 Juno 24 - - 3 1625-254 0 - - 3 1625-254 25 - - 3 1625-254 26 - - 3 1625-254 27 - - 3 1625-254 28 - - 3 1625-254 29 - - 3 1625-254 30 - - 3 1625-254 31 - - 3 1625-254 32 - - 3 1625-254 33 - - 3 1625-254 34 - - 3 1625-254 35 - - 3 1625-254 36 - - 3 1625-254 37 - - 3 1625-254 38 - - 3 1625-254 39 - - 2 1625-254 1 - - 2 1625-254 2 - - 2 1625-254 3 - - 2 1625-254 4 - - 2 1625-254 5 - - 2 1625-254 6 - - 2 1625-254 7 - - 2 1625-254 8 - - 2 1625-254 17 - - 2 1625-254 18 - - 2 1625-254 19 - - 2 1625-254 20 - - 2 1625-254 21 - - 2 1625-254 22 - - 2 1625-254 23 - - 2 1625-254 24 - - 2 nrao530 ph 9 - - 2 nrao530 ph 10 - - 2 nrao530 ph 11 - - 2 nrao530 ph 12 - - 2 nrao530 ph 13 - - 2 nrao530 ph 14 - - 2 nrao530 ph 15 - - 2 nrao530 ph 16 - - 3 nrao530 ph 17 - - 3 nrao530 ph 18 - - 3 nrao530 ph 19 - - 3 nrao530 ph 20 - - 3 nrao530 ph 21 - - 3 nrao530 ph 22 - - 3 nrao530 ph 23 - - 3 nrao530 ph 24 - - 4 IRAS16293-2422-a 0 - - 4 IRAS16293-2422-a 25 - - 4 IRAS16293-2422-a 26 - - 4 IRAS16293-2422-a 27 - - 4 IRAS16293-2422-a 28 - - 4 IRAS16293-2422-a 29 - - 4 IRAS16293-2422-a 30 - - 4 IRAS16293-2422-a 31 - - 4 IRAS16293-2422-a 32 - - 4 IRAS16293-2422-a 33 - - 4 IRAS16293-2422-a 34 - - 4 IRAS16293-2422-a 35 - - 4 IRAS16293-2422-a 36 - - 4 IRAS16293-2422-a 37 - - 4 IRAS16293-2422-a 38 - - 4 IRAS16293-2422-a 39 - - 3 IRAS16293-2422-a 9 - - 3 IRAS16293-2422-a 10 - - 3 IRAS16293-2422-a 11 - - 3 IRAS16293-2422-a 12 - - 3 IRAS16293-2422-a 13 - - 3 IRAS16293-2422-a 14 - - 3 IRAS16293-2422-a 15 - - 3 IRAS16293-2422-a 16 - - 4 IRAS16293-2422-a 17 - - 4 IRAS16293-2422-a 18 - - 4 IRAS16293-2422-a 19 - - 4 IRAS16293-2422-a 20 - - 4 IRAS16293-2422-a 21 - - 4 IRAS16293-2422-a 22 - - 4 IRAS16293-2422-a 23 - - 4 IRAS16293-2422-a 24 - - Antennas: 15: ID Name Station Diam. Long. Lat. 0 DA41 A003 12.0 m -067.45.16.5 -22.53.27.0 1 DA43 A075 12.0 m -067.45.17.9 -22.53.21.4 2 DA47 A026 12.0 m -067.45.18.8 -22.53.28.3 3 DV02 A077 12.0 m -067.45.10.1 -22.53.25.9 4 DV03 A137 12.0 m -067.45.15.2 -22.53.22.7 5 DV05 A082 12.0 m -067.45.08.3 -22.53.29.2 6 DV07 A076 12.0 m -067.45.20.5 -22.53.33.8 7 DV09 A046 12.0 m -067.45.17.0 -22.53.29.3 8 DV10 A071 12.0 m -067.45.19.9 -22.53.23.5 9 DV12 A011 12.0 m -067.45.14.4 -22.53.28.4 10 DV13 A072 12.0 m -067.45.12.6 -22.53.24.0 11 DV14 A025 12.0 m -067.45.18.7 -22.53.27.4 12 DV15 A074 12.0 m -067.45.12.1 -22.53.32.0 13 DV17 A138 12.0 m -067.45.17.1 -22.53.34.4 14 DV18 A053 12.0 m -067.45.17.3 -22.53.31.2
You can see the ID that is assigned for each source, starting with ID 0. 1924-292 is the calibrator for bandpass, Juno for amplitud (flux), 1625-254 and nrao530 ph are for phase calibration, and the remaining 7 fields of IRAS16293-2422-a are the seven pointings for our mosaic of the target source.
Spectral windows are also marked with numbers from 0 24, with 0 containing WVR information. Spws 17, 19, 21, and 23 contain the sience data (TDM mode). The CO (6-5) line emission is contained in spw 21. Spw 18, 20, 22, and 24 contain channel averages of the data in spectral windows 17, 19, 21, 23, respectively. These spws will not be used for the offline data reduction. All the remaining spw that appear in the section of sources, and that do not appear in the Spectral Windows are related to WVR measurements for each antenna, so you will not need them for the calibration. Spws 9, 11, 13, and 15 are associated with tsys measurements, and we will apply these information to the science spws later.
Visualization and exploration of Tsys and WVR tables
Next we need to check the plotting for tsys and wvr tables to make sure whether they have issues that might affect their application to the data. Whenever we see an odd behavior in the tables we need to flag the corresponding sience data to prevent wrong results in the calibration steps. The next command will plot the tsys in the next way: it will produce many plots, each one of them will show an antenna, with the four spw that tsys covers, for all the targets, and with different colors for different times, so you can trace the behavior for tsys with time, among others. Note that in spw 19 and 21, the overlap with the tsys spw (11 and 13) is not set correctly. This is due to an error in the frequencies for the tsys when the observations were done. You do not have to worry about this, since any issue coming from the error have already been handled. Note, however that the portions of the spectra that do not have tsys information cannot be used. This does not represent a problem, since that part corresponds to the edge of the baseband. Also note that the CO (6-5) line is not affected by this.
# In CASA
# Plot TDM Tsys tables, and show locations of FDM spws
os.system('rm -rf Tsysplots')
for vis in rawdata:
aU.plotbandpass('3.3_apriori_tables/'+vis+'.tsys',ms=vis,
overlay='time', xaxis='freq',
yaxis='amp',subplot=22,interactive=False,
showatm=True,
chanrange='5~122',showfdm=True,
figfile='Tsysplots/'+vis+'tsys.png')
