Transcription
CASA User Reference & CookbookRelease 4.7.2Version: March 10, 2017
Permission is granted to make and distribute verbatim copies of this manual provided the copyright noticeand this permission notice are preserved on all copies.Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permissionnotice identical to this one.Permission is granted to copy and distribute translations of this manual into another language, under theabove conditions for modified versions, except that this permission notice may be stated in a translationapproved by AUI. CASA homepage: http://casa.nrao.edu For help, comments, or corrections, please visit the NRAO helpdesk: http://help.nrao.eduor http://help.almascience.org for ALMA related questions. Data reduction guides are available at http://casaguides.nrao.edu For news, updates, critical bugs, subscribe to our CASA mailing lists: http://casa.nrao.edu/mail list.shtml Join the NRAO Users community on http://science.nrao.edu/forums
CASA Synthesis & Single Dish ReductionReference Manual & CookbookEditor: Jürgen Ott – CASA Project ScientistJeff Kern – CASA Project Managerhttp://casa.nrao.eduCASA Synthesis & Single Dish ReductionReference Manual & Cookbook,Version March 10, 2017,c 2017 National Radio Astronomy ObservatoryThe National Radio Astronomy Observatory is a facility of the National Science Foundationoperated under cooperative agreement by Associated Universities, Inc.
Contents1 Introduction1.0.1 Reference for Publications . . . . . . . . . . . . .1.1 About This Release . . . . . . . . . . . . . . . . . . . . .1.2 Obtaining CASA . . . . . . . . . . . . . . . . . . . . . .1.2.1 What’s New in Release 4.7.2 . . . . . . . . . . .1.2.1.1 CASA 4.7.2 bug fixes . . . . . . . . . .1.2.1.2 CASA 4.7.1 bug fixes . . . . . . . . . .1.2.1.3 Valid for CASA Release 4.7.0 and later:1.3 CASA Basics — Information for First-Time Users . . .1.3.1 Before Starting CASA . . . . . . . . . . . . . . .1.3.1.1 Environment Variables . . . . . . . . .1.3.1.2 Where is CASA? . . . . . . . . . . . . .1.3.2 Starting CASA . . . . . . . . . . . . . . . . . . .1.3.3 Ending CASA . . . . . . . . . . . . . . . . . . .1.3.4 What happens if something goes wrong? . . . . .1.3.5 Aborting CASA execution . . . . . . . . . . . . .1.3.6 What happens if CASA crashes? . . . . . . . . .1.3.7 Python Basics for CASA . . . . . . . . . . . . .1.3.7.1 Variables . . . . . . . . . . . . . . . . .1.3.7.2 Lists and Ranges . . . . . . . . . . . . .1.3.7.3 Indexes . . . . . . . . . . . . . . . . . .1.3.7.4 Indentation . . . . . . . . . . . . . . . .1.3.7.5 System shell access . . . . . . . . . . .1.3.7.6 Executing Python scripts . . . . . . . .1.3.8 Getting Help in CASA . . . . . . . . . . . . . . .1.3.8.1 TAB key . . . . . . . . . . . . . . . . . .1.3.8.2 help taskname . . . . . . . . . . . .1.3.8.3 help and PAGER . . . . . . . . . . . . .1.3.8.4 help par. parameter . . . . . . . . .1.3.8.5 Python help . . . . . . . . . . . . . . .1.4 Tasks and Tools in CASA . . . . . . . . . . . . . . . . .1.4.1 What Tasks are Available? . . . . . . . . . . . .1.4.2 Running Tasks and Tools . . . . . . . . . . . . .1.4.2.1 Aborting Synchronous Tasks . . . . . 041414144444545465152
1.4.31.4.41.4.51.51.6Getting Return Values . . . . . . . . . . . . . . . . . .Running Tasks Asynchronously . . . . . . . . . . . . .Setting Parameters and Invoking Tasks . . . . . . . .1.4.5.1 The scope of parameters in CASA . . . . . .1.4.5.2 The default Command . . . . . . . . . . . .1.4.5.3 The go Command . . . . . . . . . . . . . . .1.4.5.4 The inp Command . . . . . . . . . . . . . .1.4.5.5 The saveinputs Command . . . . . . . . . .1.4.5.6 The tget Command . . . . . . . . . . . . . .1.4.5.7 The tput Command . . . . . . . . . . . . . .1.4.5.8 The .last file . . . . . . . . . . . . . . . . .1.4.6 Tools in CASA . . . . . . . . . . . . . . . . . . . . . .Getting the most out of CASA . . . . . . . . . . . . . . . . .1.5.1 Your command line history . . . . . . . . . . . . . . .1.5.2 Logging your session . . . . . . . . . . . . . . . . . . .1.5.2.1 Startup options for the logger . . . . . . . .1.5.2.2 Setting priority levels in the logger . . . . .1.5.3 Where are my data in CASA? . . . . . . . . . . . . .1.5.3.1 How do I get rid of my data in CASA? . . .1.5.4 What’s in my data? . . . . . . . . . . . . . . . . . . .1.5.5 Data Selection in CASA . . . . . . . . . . . . . . . . .From Loading Data to Images . . . . . . . . . . . . . . . . . .1.6.1 Loading Data into CASA . . . . . . . . . . . . . . . .1.6.1.1 VLA: Filling data from VLA archive format1.6.1.2 Filling data from UVFITS format . . . . . .1.6.1.3 Loading FITS images . . . . . . . . . . . . .1.6.1.4 Concatenation of multiple MS . . . . . . . .1.6.2 Data Examination, Editing, and Flagging . . . . . . .1.6.2.1 Interactive X-Y Plotting and Flagging . . . .1.6.2.2 Flag the Data Non-interactively . . . . . . .1.6.2.3 Viewing and Flagging the MS . . . . . . . .1.6.3 Calibration . . . . . . . . . . . . . . . . . . . . . . . .1.6.3.1 Prior Calibration . . . . . . . . . . . . . . . .1.6.3.2 Bandpass Calibration . . . . . . . . . . . . .1.6.3.3 Gain Calibration . . . . . . . . . . . . . . . .1.6.3.4 Polarization Calibration . . . . . . . . . . . .1.6.3.5 Examining Calibration Solutions . . . . . . .1.6.3.6 Bootstrapping Flux Calibration . . . . . . .1.6.3.7 Correcting the Data . . . . . . . . . . . . . .1.6.3.8 Splitting the Data . . . . . . . . . . . . . . .1.6.3.9 UV Continuum subtraction . . . . . . . . . .1.6.3.10 Transforming the Data to a new frame . . .1.6.4 Synthesis Imaging . . . . . . . . . . . . . . . . . . . .1.6.4.1 Cleaning a single-field image or a mosaic . .1.6.4.2 Feathering in a Single-Dish image . . . . . 47475757576767677777878787879797979798080
1.6.51.6.61.6.7Self Calibration . . . . . . . . . . . . .Data and Image Analysis . . . . . . .1.6.6.1 What’s in an image? . . . . .1.6.6.2 Image statistics . . . . . . .1.6.6.3 Image values . . . . . . . . .1.6.6.4 Moments of an image cube .1.6.6.5 Image math . . . . . . . . .1.6.6.6 Regridding an Image . . . .1.6.6.7 Displaying Images . . . . . .Getting data and images out of CASA.2 Visibility Data Import, Export, and Selection2.1 CASA Measurement Sets . . . . . . . . . . . . . . . . . . . . . .2.1.1 Under the Hood: Structure of the Measurement Set . . .2.2 Data Import and Export . . . . . . . . . . . . . . . . . . . . . . .2.2.1 ALMA: Filling of Science Data Model (ASDM) data . . .2.2.1.1 Import of ASDM data with option lazy True . .2.2.2 Janksy VLA: Filling of Science Data Model (ASDM) data2.2.3 VLA: Filling data from archive format (importvla) . . .2.2.3.1 Parameter applytsys . . . . . . . . . . . . . .2.2.3.2 Parameter bandname . . . . . . . . . . . . . . .2.2.3.3 Parameter frequencytol . . . . . . . . . . . .2.2.3.4 Parameter project . . . . . . . . . . . . . . . .2.2.3.5 Parameters starttime and stoptime . . . . . .2.2.3.6 Parameter autocorr . . . . . . . . . . . . . . .2.2.3.7 Parameter antnamescheme . . . . . . . . . . . .2.2.3.8 Parameter evlabands . . . . . . . . . . . . . .2.2.4 Import ATCA and CARMA data . . . . . . . . . . . . . .2.2.5 Import MIRIAD visibilities (importmiriad) . . . . . . . .2.2.6 Import ATCA RPFITS data (importatca) . . . . . . . .2.2.7 UVFITS Import and Export . . . . . . . . . . . . . . . .2.2.7.1 Import using importuvfits . . . . . . . . . . .2.2.7.2 Import using importfitsidi . . . . . . . . . .2.2.7.3 Export using exportuvfits . . . . . . . . . . .2.2.8 Handling Measurement Set metadata and data . . . . . .2.2.9 Summarizing your MS (listobs) . . . . . . . . . . . . . .2.2.10 MMS summary (listpartition) . . . . . . . . . . . . . .2.2.11 Listing MS data (listvis) . . . . . . . . . . . . . . . . .2.2.12 Listing and manipulating MS metadata (vishead) . . . .2.2.13 MS statistics (visstat) . . . . . . . . . . . . . . . . . . .2.2.14 Concatenating multiple datasets (concat) . . . . . . . . .2.3 Data Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.3.1 General selection syntax . . . . . . . . . . . . . . . . . . .2.3.1.1 String Matching . . . . . . . . . . . . . . . . . .2.3.2 The field Parameter . . . . . . . . . . . . . . . . . . . 14114115
2.3.32.3.4The spw Parameter . . . . . . . . . . . . . . . . .2.3.3.1 Channel selection in the spw parameterThe selectdata Parameters . . . . . . . . . . .2.3.4.1 The antenna Parameter . . . . . . . . .2.3.4.2 The scan Parameter . . . . . . . . . . .2.3.4.3 The timerange Parameter . . . . . . .2.3.4.4 The uvrange Parameter . . . . . . . . .2.3.4.5 The correlation Parameter . . . . . .2.3.4.6 The intent Parameter . . . . . . . . .2.3.4.7 The observation Parameter . . . . . .2.3.4.8 The feed Parameter . . . . . . . . . . .2.3.4.9 The msselect Parameter . . . . . . . .3 Data Examination and Editing3.1 Plotting and Flagging Visibility Data in CASA . . . . . . . . . .3.2 Managing flag versions with flagmanager . . . . . . . . . . . . .3.3 X-Y Plotting and Editing of the Data . . . . . . . . . . . . . . .3.3.1 MS Plotting and Editing using plotms . . . . . . . . . . .3.3.1.1 Loading and Selecting Data . . . . . . . . . . . .3.3.1.2 A Brief Note Regarding plotms Memory Usage .3.3.1.3 Plot Axes . . . . . . . . . . . . . . . . . . . . . .3.3.1.4 Calibration Library . . . . . . . . . . . . . . . .3.3.1.5 Tools . . . . . . . . . . . . . . . . . . . . . . . .3.3.1.6 Interactive Flagging in plotms . . . . . . . . . .3.3.1.7 Averaging Data . . . . . . . . . . . . . . . . . .3.3.1.8 Plot Symbols . . . . . . . . . . . . . . . . . . . .3.3.1.9 Summarizing Data . . . . . . . . . . . . . . . . .3.3.1.10 Defining Frequency and Velocity . . . . . . . . .3.3.1.11 Shifting the Phase Center . . . . . . . . . . . . .3.3.1.12 Plot Ranges . . . . . . . . . . . . . . . . . . . .3.3.1.13 Plot Labels . . . . . . . . . . . . . . . . . . . . .3.3.1.14 Grid Lines . . . . . . . . . . . . . . . . . . . . .3.3.1.15 Legend . . . . . . . . . . . . . . . . . . . . . . .3.3.1.16 The Options Tab . . . . . . . . . . . . . . . . . .3.3.1.17 Iteration . . . . . . . . . . . . . . . . . . . . . .3.3.1.18 Overplotting . . . . . . . . . . . . . . . . . . . .3.3.1.19 Plotting Multiple Data Sets . . . . . . . . . . . .3.3.1.20 Saving your plot . . . . . . . . . . . . . . . . . .3.3.1.21 Exiting plotms . . . . . . . . . . . . . . . . . . .3.3.2 Plotting and Editing using plotxy . . . . . . . . . . . . .3.3.2.1 GUI Plot Control . . . . . . . . . . . . . . . . .3.3.2.2 The selectplot Parameters . . . . . . . . . . .3.3.2.3The iteration parameter . . . . . . . . . . . . .3.3.2.4The overplot parameter . . . . . . . . . . . . . .3.3.2.5The plotrange parameter . . . . . . . . . . . . .116117118118120120121122122122123123.124. 124. 125. 126. 126. 128. 129. 131. 133. 134. 135. 136. 138. 138. 139. 140. 140. 140. 141. 141. 141. 141. 142. 142. 144. 144. 145. 148. 149. 150. 150. 150
3.43.53.63.3.2.6The plotsymbol parameter . . . . . . . . .3.3.2.7The showflags parameter . . . . . . . . . .3.3.2.8The subplot parameter . . . . . . . . . . .3.3.2.9 Averaging in plotxy . . . . . . . . . . . . .3.3.2.10 Interactive Flagging in plotxy . . . . . . .3.3.2.11 Flag extension in plotxy . . . . . . . . . .3.3.2.12 Setting rest frequencies in plotxy . . . . .3.3.2.13 Printing from plotxy . . . . . . . . . . . .3.3.2.14 Exiting plotxy . . . . . . . . . . . . . . . .3.3.2.15 Example session using plotxy . . . . . . .3.3.3 Plotting antenna positions using plotants . . . . .3.3.4 Plotting uv-coverages plotuv . . . . . . . . . . . . .Data Flagging using flagdata . . . . . . . . . . . . . . . .3.4.1 The action parameter . . . . . . . . . . . . . . . . .3.4.2 Flagging Modes . . . . . . . . . . . . . . . . . . . . .3.4.2.1 Manual Flag/Unflag . . . . . . . . . . . . .3.4.2.2 List . . . . . . . . . . . . . . . . . . . . . .3.4.2.3 Clip . . . . . . . . . . . . . . . . . . . . . .3.4.2.4 Shadow . . . . . . . . . . . . . . . . . . . .3.4.2.5 Quack . . . . . . . . . . . . . . . . . . . . .3.4.2.6 Elevation . . . . . . . . . . . . . . . . . . .3.4.2.7 Tfcrop . . . . . . . . . . . . . . . . . . . .3.4.2.8 Rflag . . . . . . . . . . . . . . . . . . . . .3.4.2.9 Extend . . . . . . . . . . . . . . . . . . . .3.4.2.10 Unflag . . . . . . . . . . . . . . . . . . . . .3.4.2.11 Summary . . . . . . . . . . . . . . . . . . .Command-based flagging using flagcmd . . . . . . . . . . .3.5.1 Input modes inpmode . . . . . . . . . . . . . . . . .3.5.1.1 Input mode ’table’ . . . . . . . . . . . . . .3.5.1.2 Input flag mode ’list’ . . . . . . . . . . . .3.5.1.3 Input flag mode ’xml’ . . . . . . . . . . . .3.5.2 Operation types action . . . . . . . . . . . . . . . . .3.5.2.1 Apply flags — optype option ’apply’ . . . .3.5.2.2 Unapply flags — action option ’unapply’ .3.5.2.3 List flags — action ’list’ . . . . . . . . . .3.5.2.4 Plot flags — action ’plot’ . . . . . . . . .3.5.2.5 Clear flags — action ’clear’ . . . . . . . .3.5.2.6 Extract Flag Commands— action ’extract’3.5.3 Flagging command syntax . . . . . . . . . . . . . . .Browse the Data . . . . . . . . . . . . . . . . . . . . . . . 1811811821821821831854 Synthesis Calibration1894.1 Calibration Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1894.2 The Calibration Process — Outline and Philosophy . . . . . . . . . . . . . . . . . . . 1914.2.1 The Philosophy of Calibration in CASA . . . . . . . . . . . . . . . . . . . . . 194
4.34.44.2.2 Keeping Track of Calibration Tables . . . . . . . . . . . . . . . . . . . . . .4.2.3 The Calibration of traditional VLA data in CASA . . . . . . . . . . . . . .4.2.4 Loading Jansky VLA data in CASA . . . . . . . . . . . . . . . . . . . . . .Preparing for Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.3.1 Weight initialization and WEIGHT SPECTRUM . . . . . . . . . . . . . . .4.3.2 System Temperature and Switched-Power Corrections . . . . . . . . . . . .4.3.3 Antenna Gain-Elevation Curve Calibration . . . . . . . . . . . . . . . . . .4.3.4 Atmospheric Optical Depth Correction . . . . . . . . . . . . . . . . . . . . .4.3.4.1 Determining opacity corrections for modern VLA data . . . . . . .4.3.4.2 Determining opacity corrections for VLA data . . . . . . . . . . .4.3.5 Setting the Flux Density Scale using (setjy) . . . . . . . . . . . . . . . . .4.3.5.1 Using Calibration Models for Resolved Sources . . . . . . . . . . .4.3.6 Correction for delay and antenna position offsets using gencal . . . . . . .4.3.7 Applying Jansky VLA switched power or ALMA Tsys using gencal . . . .4.3.8 Generate a gain table based on Water Vapor Radiometer data wvrgcal . .4.3.8.1 Statistical parameters shown in the logger output of wvrgcal . . .4.3.8.2 Antenna position calculation . . . . . . . . . . . . . . . . . . . . .4.3.8.3 Spectral window selection . . . . . . . . . . . . . . . . . . . . . . .4.3.9 Ionospheric corrections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.3.10 Other a priori Calibrations and Corrections . . . . . . . . . . . . . . . . . .Solving for Calibration — Bandpass, Gain, Polarization . . . . . . . . . . . . . . .4.4.1 Common Calibration Solver Parameters . . . . . . . . . . . . . . . . . . . .4.4.1.1 Parameters for Specification : vis and caltable . . . . . . . . .4.4.1.2 Selection: field, spw, selectdata, intent, and observation . .4.4.1.3 Prior Calibration and Correction: parang . . . . . . . . . . . . .4.4.1.4 Previous Calibration: gaintable, gainfield, interp and spwmap4.4.1.5 Solving: solint, combine, preavg, refant, minblperant, minsnr4.4.1.6 Action: append and solnorm . . . . . . . . . . . . . . . . . . . .4.4.2 Spectral Bandpass Calibration (bandpass) . . . . . . . . . . . . . . . . . .4.4.2.1 Bandpass Normalization . . . . . . . . . . . . . . . . . . . . . . .4.4.2.2 B solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.4.2.3 BPOLY solutions . . . . . . . . . . . . . . . . . . . . . . . . . . .4.4.2.4 What if the bandpass calibrator has a significant slope? . . . . . .4.4.3 Complex Gain Calibration (gaincal) . . . . . . . . . . . . . . . . . . . . .4.4.3.1 Polarization-dependent Gain (G) . . . . . . . . . . . . . . . . . . .4.4.3.2 Polarization-independent Gain (T) . . . . . . . . . . . . . . . . . .4.4.3.3 GSPLINE solutions . . . . . . . . . . . . . . . . . . . . . . . . . .4.4.3.4 Antenna Delays — ’K’ solutions . . . . . . . . . . . . . . . . . . .4.4.3.5 Cross-Hand Delays — ’KCROSS’ solutions . . . . . . . . . . . . .4.4.4 Establishing the Flux Density Scale (fluxscale) . . . . . . . . . . . . . .4.4.4.1 Using Resolved Calibrators . . . . . . . . . . . . . . . . . . . . . .4.4.5 Instrumental Polarization Calibration (D,X) . . . . . . . . . . . . . . . . . .4.4.5.1 Heuristics and Strategies for Polarization Calibration . . . . . . .4.4.5.2 A Note on channelized polarization calibration . . . . . . . . . . 229230231232233233233235237238239
4.4.5.34.54.64.7A Polarization Calibration Example - Circular Feed Basis (e.g.,VLA ν 1 GHz) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.4.5.4 A Polarization Calibration Example - Linear Feed Basis (e.g., ALMA,VLA ν 1 GHz) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.4.6 Baseline-based Calibration (blcal) . . . . . . . . . . . . . . . . . . . . . . . .Plotting and Manipulating Calibration Tables . . . . . . . . . . . . . . . . . . . . . .4.5.1 Plotting Calibration Solutions (plotcal) . . . . . . . . . . . . . . . . . . . .4.5.1.1 Examples for plotcal . . . . . . . . . . . . . . . . . . . . . . . . . .4.5.2 Plotting the Bandpass with (plotbandpass) . . . . . . . . . . . . . . . . . .4.5.3 Listing calibration solutions with (listcal) . . . . . . . . . . . . . . . . . . .4.5.4 Calibration table statistics (calstat) . . . . . . . . . . . . . . . . . . . . . . .4.5.5 Calibration Smoothing (smoothcal) . . . . . . . . . . . . . . . . . . . . . . . .4.5.6 Calibration Interpolation and Accumulation (accum) . . . . . . . . . . . . . .4.5.6.1 Interpolation using (accum) . . . . . . . . . . . . . . . . . . . . . . .4.5.6.2 Incremental Calibration using (accum) . . . . . . . . . . . . . . . . .Application of Calibration to the Data . . . . . . . . . . . . . . . . . . . . . . . . . .4.6.1 Application of Calibration (applycal) . . . . . . . . . . . . . . . . . . . . . .4.6.2 Examine the Calibrated Data . . . . . . . . . . . . . . . . . . . . . . . . . . .4.6.3 Resetting the Calibration Models (delmod and clearcal) . . . . . . . . . . .Other Calibration and UV-Plane Analysis Options . . . . . . . . . . . . . . . . . . .4.7.1 Splitting out Calibrated uv data (split) . . . . . . . . . . . . . . . . . . . .4.7.1.1 Averaging in split . . . . . . . . . . . . . . . . . . . . . . . . . . .4.7.2 Recalculation of uvw values (fixvis) . . . . . . . . . . . . . . . . . . . . . .4.7.3 Hanning smoothing of uv data (hanningsmooth) . . . . . . . . . . . . . . . .4.7.4 MStransform (mstransform) . . . . . . . . . . . . . . . . . . . . . . . . . . .4.7.4.1 Data selection and re-indexing . . . . . . . . . . . . . . . . . . . . .4.7.4.2 Data partition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.7.4.3 On-the-fly calibration . . . . . . . . . . . . . . . . . . . . . . . . . .4.7.4.4 Time average . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.7.4.5 Channel average . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.7.4.6 Hanning smooth . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.7.4.7 Combination of spectral windows . . . . . . . . . . . . . . . . . . .4.7.4.8 Spectral regridding and reference frame transformation . . . . . . .4.7.4.9 Separation of spectral windows . . . . . . . . . . . . . . . . . . . . .4.7.5 Model subtraction from uv data (uvsub) . . . . . . . . . . . . . . . . . . . . .4.7.6 UV-Plane Continuum Subtraction (uvcontsub) . . . . . . . . . . . . . . . . .4.7.7 Spectral regridding of the MS (cvel) . . . . . . . . . . . . . . . . . . . . . . .4.7.8 UV-Plane Model Fitting (uvmodelfit) . . . . . . . . . . . . . . . . . . . . . .4.7.9 Reweighing visibilities based on their scatter (statwt) . . . . . . . . . . . . .4.7.10 Change the signs of visibility phases (conjugatevis) . . . . . . . . . . . . . .4.7.11 Manipulation of Ephemeris Objects . . . . . . . . . . . . . . . . . . . . . . .4.7.11.1 Ephemeris tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.7.11.2 Using fixplanets to attach ephemerides to a field of a Measurement Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.7.11.3 Use of the ephemeris after attachment . . . . . . . . . . . . . . . . 275277280282284284285285286
4.84.7.11.4 Spectral frame transformation to the rest frameobject in task cvel . . . . . . . . . . . . . . . .4.7.11.5 Ephemerides in ALMA datasets . . . . . . . . .Examples of Calibration . . . . . . . . . . . . . . . . . . . . . . .5 Synthesis Imaging5.1 Imaging Tasks Overview . . . . . . . . . . . . .5.2 Common Imaging Task Parameters . . . . . . .5.2.1 Parameter cell . . . . . . . . . . . . .5.2.2 Parameter field . . . . . . . . . . . .5.2.3 Parameter imagename . . . . . . . . . .5.2.4 Parameter imsize . . . . . . . . . . . .5.2.5 Parameter mode . . . . . . . . . . . . .5.2.5.1 Mode mfs . . . . . . . . . . .5.2.5.2 Mode channel . . . . . . . . .5.2.5.3 Mode frequency . . . . . . .5.2.5.4 Mode velocity . . . . . . . .5.2.5.5 Sub-parameter interpolation5.2.6 Parameter resmooth . . . . . . . . . .5.2.7 Parameter phasecenter . . . . . . . .5.2.8 Parameter restfreq . . . . . . . . . .5.2.9 Parameter spw . . . . . . . . . . . . . .5.2.10 Parameter stokes . . . . . . . . . . . .5.2.11 Parameter uvtaper . . . . . . . . . . .5.2.12 Parameter weighting . . . . . . . . . .5.2.12.1 ’natural’ weighting . . . . .5.2.12.2 ’uniform’ weighting . . . . .5.2.12.3 ’superuniform’ weighting . .5.2.12.4 ’radial’ weighting . . . . . .5.2.12.5 ’briggs’ weighting . . . . . .5.2.12.6 ’briggsabs’ weighting . . . .5.2.13 Parameter vis . . . . . . . . . . . . . .5.2.14 Primary beams in imaging . . . . . . .5.3 Deconvolution using CLEAN (clean) . . . . .5.3.1 Parameter psfmode . . . . . . . . . . .5.3.1.1 The clark algorithm . . . . .5.3.1.2 The hogbom algorithm . . . . .5.3.1.3 The clarkstokes algorithm .5.3.2 The multiscale parameter . . . . . . .5.3.3 Parameter gain . . . . . . . . . . . . .5.3.4 Parameter imagermode . . . . . . . . .5.3.4.1 Sub-parameter cyclefactor .5.3.4.2 Sub-parameter cyclespeedup5.3.4.3 Sub-parameter ftmachine . .5.3.4.4 Sub-parameter mosweight . .of the. . . . . . . . . .ephemeris. . . . . . . 286. . . . . . . 287. . . . . . . 287.288. 288. 289. 289. 290. 290. 290. 291. 291. 293. 294. 295. 296. 296. 296. 297. 297. 298. 298. 299. 299. 300. 300. 300. 301. 301. 302. 302. 303. 306. 307. 307. 307. 307. 308. 308. 310. 311. 311. 312
5.45.55.65.75.85.95.105.115.125.135.3.4.5 Sub-parameter scaletype . . . . . . . . . .5.3.4.6 The threshold revisited . . . . . . . . . . .5.3.5 Parameter interactive . . . . . . . . . . . . . . . .5.3.6 Parameter mask . . . . . . . . . . . . . . . . . . . . .5.3.6.1 Setting clean boxes . . . . . . . . . . . . . .5.3.6.2 Using clean mask images . . . . . . . . . . .5.3.7 Parameter minpb . . . . . . . . . . . . . . . . . . . .5.3.8 Parameter modelimage . . . . . . . . . . . . . . . . .5.3.9 Parameter niter . . . . . . . . . . . . . . . . . . . .5.3.10 Parameter pbcor . . . . . . . . . . . . . . . . . . . .5.3.11 Parameter restoringbeam . . . . . . . . . . . . . . .5.3.12 Parameter threshold . . . . . . . . . . . . . . . . . .5.3.13 Parameter gridmode . . . . . . . . . . . . . . . . . .5.3.14 Interactive Cleaning — Example . . . . . . . . . . . .5.3.15 Mosaic imaging . . . . . . . . . . . . . . . . . . . . . .5.3.16 Heterogeneous imaging . . . . . . . . . . . . . . . . . .5.3.17 Polarization imaging . . . . . . . . . . . . . . . . . . .5.3.18 Wide-field imaging and deconvolution in clean . . . .5.3.18.1 Outlier fields . . . . . . . . . . . . . . . . . .5.3.18.2 Setting up w-projection . . . . . . . . . . . .5.3.18.3 Setting up faceting . . . . . . . . . . . . . . .5.3.18.4 Combination of w-projection and faceting . .Refactored clean: tclean . . . . . . . . . . . . . . . . . . . .Primary Beam Correction (impbcor, widebandpbcor) . . . .Combined Single Dish and Interferometric Imaging (feather)5.6.1 Visual Interface for feather (casafeather) . . . . . .Making Deconvolution Masks or Box Regions . . . . . . . . .5.7.1 Making Deconvolution Regions from an Image (boxit)Insert an Image Model (ft) . . . . . . . . . . . . . . . . . . .Pre-Gridding Visibilities (msuvbin) . . . . . . . . . . . . . . .Image-plane deconvolution (deconvolve) . . . . . . . . . . .Self-Calibration . . . . . . . . . . . . . . . . . . . . . . . . . .Parallelized Cleaning . . . . . . . . . . . . . . . . . . . . . . .Examples of Imaging . . . . . . . . . . . . . . . . . . . . . . .6 Image Analysis6.1 Common Image Analysis Task Parameters6.1.1 Input Image (imagename) . . . . .6.1.2 Region Selection (box) . . . . . . .6.1.3 Plane Selection (chans, stokes) .6.1.4 Lattice Expressions (expr) . . . .6.1.5 Masks (mask) . . . . . . . . . . . .6.1.6 Regions (region) . . . . . . . . . .6.2 Image Header Manipulation (imhead) . .6.2.1 Examples for imhead . . . . . . . .
CASA Synthesis & Single Dish Reduction Reference Manual & Cookbook Editor: Jurgen Ott - CASA Project Scientist Jeff Kern - CASA Project Manager
