From gmoellen@aoc.nrao.edu Tue Apr 16 09:56:32 2002 Date: Mon, 15 Apr 2002 22:47:51 -0600 (MDT) From: George Moellenbrock Reply-To: aips2-naug@donar.cv.nrao.edu To: aips2-naug@zia.aoc.NRAO.EDU Subject: [Aips2-naug] VLA cookbook (GRA chapter) Hi gang, At long last, the lastest revision of the cookbook chapter is ready for comments from you. Please find it in the daily build (no earlier than Tues morning) at: http://aips2.nrao.edu/daily/docs/gettingresults/grvol3/grvol3.html (Click on "VLA reduction") Among the improvements in this revision: 1) Better description of MS (and moved nearer beginning). (This section still requires some improvement, mainly to describe how selection works.) 2) Calibration formalism description moved nearer beginning. 3) Added summary list of calibration steps. I hope this gives readers a digestable sense of what they are in for in the rest of the doc. I think it could look more like a checklist---a quick reference that users could follow to help adapt the steps to their own datasets. 4) Added section on operation of the calibrater tool, emphasizing the use of the setapply/setdata functions. I hope this helps to clear up some confusion I've noticed among some of you recently. 5) Changed the continuum polarimetry dataset to one which generates an interesting image (the 0957+561 grav lens). This new dataset follows the standard calibration style better. 6) Some general clean-up of typos, style, and layout. Plenty more of this is in the works, including some suggestions I already have from some of you, but don't have with me in GB. Of course, there are still a several caveats NAUG readers should be aware of (i.e., don't bother complaining about these issues): A) The data examination and editing sections have not been edited yet. These sections will be overhauled as developments/fixes in flagger are implemented over the next month or so. B) The aquisition of the Q,U model for polarization calibration of the continuum dataset is still glossed over. A function will be added to the calibrater tool this week that makes this very easy for point source calibrators, and I will update the doc as soon as this feature is available. C) The handling of RL phase corrections (pol P.A. calibration) is not yet described. One drawback of the lens dataset is that it has only one spectral window, so this calibration can be handled in the rendering of the pol image in the viewer. For multi-IF datasets, this calibration must be measured and applied before imaging (unless the IFs are imaged separately), so that the IFs are coherent in the cross-hands. I am currently working on a mechanism for applying this calibration, and the point source flux density estimator mentioned above will be the way you measure the required adjustment. Stay tuned. D) There is as yet no description of handling detailed channel selection in calibrating the spectral line dataset. I am waiting for fixes in the code. E) A description of interactive cleaning (including drawing clean boxes) is waiting for implementation of this in imager. (Kumar is working on this currently, with input from Ed.) F) I didn't have time to put in a decent decription of self-calibration. I will add it ASAP. Incremental calibration will soon be available and will be an important part of the description of selfcal. G) Info on how to do opac, gain and baseline corrections will be added when these features become available in the next week or so. H) The calibrater.plotcal function is currently broken when plotting cal tables for the lens dataset (field selection is wacky). I am working on this. That's enough caveats. Despite this list of specifics, I think the doc is much improved, so I hope to hear some good comments, especially from those of you who haven't read it in detail yet. In my view, the above deficiencies are the major things that have to happen before the summer school and I am confident that we can achieve them in plenty of time. Beyond these items, the doc mainly requires a good read to help me clarify any remaining subtlety or vagueness, and weed out any remaining errors. Thanks a lot for your help. As for the scripts, I have extracted the glish directly from the doc and tested them successfully. - the link to the spectral line script takes you to the right thing (this has been in place since before the release) - the link to the new continuum dataset is not yet working (as I write this Monday night), but I will be fixing it first thing Tues morning, hopefully before you read this. I will send an email confirming. By the end of Tuesday, I expect to have this scripts fully published in the Recipes page. Talk to you on Wed, George -- _______________________________________________ Aips2-naug mailing list Aips2-naug@listmgr.cv.nrao.edu http://listmgr.cv.nrao.edu/mailman/listinfo/aips2-naug