Simdata CASA 3.1
From CASA Guides
mosaic simulation task: mosaic simulation task (prototype): This task simulates interfermetric observations (currently only ALMA can be done easily). New functionality is actively being added, so if you have changed versions of CASA, check the inputs carefully. Please contact CASA experts with any questions, especially about features noted below as *experimental* ------------------------------- project -- root filename for all output files. ------------------------------- modifymodel -- change the coordinate system of the model sky image? * if graphics selected, display the rescaled model image skymodel -- if modifymodel=False, use this as the sky model. * if modifyimage=True, use this as the starting point, modify it write the output to a different image (default $project.skymodel) and use that new image as the sky model inbright -- peak brightness in Jy/pixel, or "" for unchanged * NOTE: "unchanged" will take the numerical values in your image and assume they are in Jy/pixel, even if it says some other unit in the header. indirection -- central direction, or "" for unchanged incell -- spatial pixel size, or "" for unchanged incenter -- frequency of center channel e.g. "89GHz", or "" for unchanged inwidth -- width of channels, or "" for unchanged - this should be a string representing a quantity with units e.g. "10MHz" * NOTE: only works reliably with frequencies, not velocities * NOTE: it is not possible to change the number of spectral planes of the sky model, only to relabel them with different frequencies That kind of regridding can be accomplished with the CASA toolkit. ------------------------------- setpointings -- calculate a map of pointings, or if false, provide ptgfile * if graphics selected, display the pointings shown on the model image ptgfile -- a text file specifying directions in the same format as the example, and optional integration times, e.g. #Epoch RA DEC TIME(optional) J2000 23h59m28.10 -019d52m12.35 10.0 * if the time column is not present in the file, it will use "integration" for all pointings. * NOTE: at this time the file should contain only science pointings: simdata will observe these, then optionally the calibrator, then the list of science pointings again, etc, until totaltime is used up. integration --- Time interval for each integration e.g '10s' * NOTE: to simulate a "scan" longer than one integration, use setpointings to generate a pointing file, and then edit the file to repeat each pointing several times before moving to the next point. direction -- mosaic center direction e.g 'J2000 19h00m00 -40d00m00' * can optionally be a list of pointings * otherwise simdata will pack mapsize according to maptype mapsize -- angular size of map * set to "" to span the model image maptype -- hexagonal or linear pointingspacing -- spacing in between beams e.g '1arcsec' ------------------------------- predict -- calculate visibilities from skymodel (which may have been modified above, (optionally) complist, and $ptgfile (which may have been generated above) * if graphics selected, display the array (like plotants), the uv coverage, the synthesized (dirty) beam, and ephemeris information refdate -- central time of simulated observation eg: '2012/05/21/22:05:00' * NOTE: observations are currently centered at the nearest transit * totaltime --- total time of observation e.g '7200s' antennalist -- ascii file containing antenna positions. each row has x y z coordinates and antenna diameter; header lines are required to specify the observatory name and coordinate system e.g. # observatory=ALMA # coordsys=UTM # datum=WGS84 # zone=19 * standard arrays are found in your CASA data repository, os.getenv("CASAPATH").split()[0]+"/data/alma/simmos/" * if "", will not not produce an interferometric MS * NEW: a string of the form "alma;0.5arcsec" will be parsed into a full 12m ALMA configuration. This only works for full ALMA and may fail to find the standard configuration files on some systems - see casaguides.nrao.edu caldirection -- *NEW* an unresolved calibrator can be observed interleaved with the science pointings. This feature is experimental, so please contact us with any questions. * The calibrator is implemented as a point source clean component with this direction and flux=calflux sdantlist -- antenna position file with antennas to be used for single dish or total power simulation * if "", will not produce a total power MS sdant -- the index of the antenna in the list to use for total power. defaults to the first antenna on the list. -------------------------------