Purpose of this page
: instructions for people within the project to make example ES simulations
Simulating from component lists:
- For a handful of point sources, this is easier than making a model sky image
- Caveat: complist-only functionality was re-enabled only in Sept '10 so you may find "features". I amost exclusively use casapy-active. I tested it briefly on casapy-test r12608, so you can try that; it almost certainly doesn't work on casapy-stable.
cl.addcomponent(dir="J2000 18h00m00s -23d0m00.s", flux=.01, freq='245.0GHz')
cl.addcomponent(dir="J2000 18h00m00.072s -23d0m01.s", flux=.005, freq='245.0GHz')
cl.addcomponent(dir="J2000 18h00m00.144s -23d0m00.s", flux=.0025, freq='245.0GHz')
cl.addcomponent(dir="J2000 18h00m00.072s -22d59m59.s", flux=.001, freq='245.0GHz')
Richard Hills suggests this example configuration (not optimized): 250m_Array_2.pdf
Al Wootten translated the pad names into locations, and this is the sindata-readable cfg formatted file: ES.250m.20100902.cfg
Here's an example of 2mm PWV, the 4-point-source componentlist just described, at zenith (remember that simdata observes at transit, so you have to simulate different elevations by changing the dec. C'est la vie.
project = 'es.1mm.el40.1min.2mmpwv'
modifymodel = False
setpointings = True
predict = True
complist = '1mm.+27.cl'
antennalist = 'ES.250m.20100902.cfg'
totaltime = '60s'
thermalnoise = 'tsys-atm'
user_pwv = 2.0
image = True
vis = '$project.noisy.ms'
imsize = [128, 128]
cell = '0.1arcsec'
niter = 5000
threshold = '5e-5Jy'
analyze = True
graphics = "both"
verbose = True
overwrite = True
Making model images:
If you want to make a model image in CASA from components (e.g. to edit the spectra of sources in a cube -- components don't yet cupport nontrivial spectra, or use component shapes other than gaussians), here are example incantations:
# create blank im (100x100 pixels, 1 stokes, 1 freq bin i.e. continuum)
# get its coordsys:
# you don't need to do this, but deg is nicer than arcmin for eg. the
# ref posn
# make pixel size 1 arcsec:
# set refdir (ra/dec in degrees)
# set image freq to 672 GHz
# set bandwidth to 2GHz (there may be a factor of two here I should
# sanity check - look in logger:
# now reattach the coordsys to the image:
# this should look sensible:
# and now you can stick in the components:
# and the max in here better no longer be zero:
# just to make sure it gets written to disk
# now you can use my.image in simdata.