Simdata Enhancements

For 3.2:

  • B79 Tsys consistent with OT calculator - did something 4/12 but not 100% sure its right
  • cycle0 configs done 4/4/11

This is a collection of comments from NAASC staff and users regarding the CASA tool simdata and the guides or tutorial material created to help the user.

The Software

  • I'd like to get a simple command line comment set listing shadowing for the source, with antenna set, amount and times. I think that will be particularly informative for the ES arrays, for which we have antennas observing for fuller tracks than they may observe on in the future, and where perhaps half the observations will be in the compact array. – Al [too complex to force into 3.2, trivial to release as a py script on casaguides later]
  • I think we need to do some combination of: clean up uninteresting intermediate simdata data/image products and-or organize the output in to subdirectories – Crystal, seconded by Kartik done 4/8/11
  • The documentation should also describe what the products are – ideally in the help simdata part and the fits headers themselves. - Kartik [documentation done 4/8/11, except that of course CASA doesn't make fits files. will investigate putting comments in CASA imhead, but not for 3.2]

From Scott + Kartik

  • Slight changes to the wording you get when you type “inp(simdata)”

1) inbright – "set surface brightness of brightest pixel and scale map accordingly" done 4/12

2) refdate – maybe say that for now this parameter isn’t used already says "see help"

3) project = ‘sim’ # -> change the word “root” to “root prefix” for output file names done 4/12

4) complist = ‘’ # Give an example of how a component may be defined? Or have a sample component list file included with the distribution? [copy from https://safe.nrao.edu/wiki/bin/view/ALMA/EarlyScienceSims to casaguides - no action for 3.2]

5) totaltime - If the inttime x # of pointings > total time then simdata exits inelegantly – perhaps add here that total time must exceed the number of integration time x pointings – but then pointings are not known apriori. Perhaps just add the error line here to guide the user.
[need better understanding before acting RI 4/12]

  • Slight changes to the wording when you type “help(simdata)”

1) vis = maybe state here what vis to use for the case of thermal noise done 4/12

2) vis – I think this is called “ms” in the help corrected 4/12

3) showdifference and showfidelity – this should be explained in more detail (perhaps as in the email you sent to us) done some 4/12 - see if its enough

  • Here is my advice for changing the default settings for the parameters

1) mapsize = “” (make the default the entire map) ok done 4/12 - may cause issues with components - if someone could test with 1 component and with several components spread over larger area than a PB before the release that'd be great

2) pointingspacing = “” (make the default 0.5, or maybe a little smaller, times the PB) done 4/12

3) image = T (I know that we already talked about this) something fscked with xml parser. trying to fix 4/12 got it.

4) overwrite = T (this might be dangerous, but otherwise simdata doesn’t produce what you want! ok. done 4/12

The Guide

  • The first simdata tutorial on the casaguides pages is M51 is quite involved. I'd suggest reordering the tutorials so that the Protoplanetary disk is the first example since it requires many fewer steps and thoughts. The M51 example would come naturally after it. – Doug
  • The M51 one is very complex, of course you can learn a lot since it modifies a lot of things to adjust to ALMA. On the other hand, I found it much better explained that the disk one, which is easy to follow, just do the simulation without model modifications or adding noise (good for dummies), but there was missing info in particular concerning what the results of the plots mean! - Nuria
  • I don't understand why in the M51 guide we do an importfits, while not in the disk one and says "simdata will create psim2.skymodel CASA image since this model is a fits file" - Nuria
  • Antennalist: how do we know the possible antenna configurations and which one to use – this needs to be added to the guides. – Nuria
  • In the disk guide, after image=True, the strokes parameter is not set and when running simdata it gives an error. Although I saw it was in red when doing inp(simdata), I was not sure what I had to put in here to get it to be correct. - Nuria
  • 30Dor should be a guide as well – it was very easy to follow in the simdata talk - Nuria

The Tutorial Materials

  • It would be good to have a more realistic example than 30 Dor – perhaps a model. We need to create something that can really help users understand the expected flux at ALMA wavelengths and get a feeling for the real S/N – Brenda (also echoed by Crystal and Todd who said, “simdata was created specifically to get a good idea of the S/N with ALMA observations”.


Topic revision: r6 - 2011-04-12, RemyIndebetouw
 

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