IonosphericCalibration
James M Anderson, 18 January 2006
Here are some scripts related to my IonosphericCalibration work.
n05l2pt.py This file is being used to do the main calibration of my N05L2 EVN test observations for the ionosphere. It was developed before Cormac really began work on developing the ParselTongue EVN pipeline, so you should check out Cormac's stuff to see a more refined pipeline system for the EVN.
get_small_source_stats_main provides a function to get information about an image, similar to the verb IMSTAT in AIPS. It finds the peak and integrated brightness of a source (in Jy/beam and Jy), as well as the RMS level away from the source, ignoring edge pixels in the image.
Also of interest might be the function self_cal_source which provides a very basic self-calibration functionality. It is rather complex, so you will have to look at the code to see what is going on. SCMAP and similar tasks are already available with AIPS, but I have not found them to be very useful, and prefer to keep lots of control over the self-calibration process.
The main part of the software in this file is geared toward testing different ionospheric models, and therefore many oeprations such as phase referencing of sources are repeated over and over. You might have a look at process_phase_reference_data to see what is going on. This will also need the file n05l2pr.py
The other work for the ionosphere involves creating a new AIPS table (AI) and putting ionospheric data into that table, and then moving the information to make a new CL table. A preliminary set of functions to do this can be found in Albus_Iono.py . Have a look at the apply_AI_table_to_CL_table function to see how to read from an old CL table and create a new one.
Calibrating narrow band data using solutions from wide band data
Huib Jan van Langevelde, 19 January 2006
The files mixedcal.py and snatch.py are a high level script and calibration routine which transfers wide band delay and phase solutions to narrow band data, by extrapolating to the proper frequency in the narrow band data.
The script linecal.py is a script to read specific data from the EVN archive and average it down in time, doing some standard calibration. It requires a file with metadata (el032com.txt).
The new EVN pipeline
Cormac Reynolds, 11 Sep 2006
A new pipeline for data from the EVN data processor at JIVE is being developed using ParselTongue.
The main pipeline script is EVN.py. It uses three Python modules:
evn_aips_tasks.py: Shortcut functions for executing AIPS tasks with most parameters defaulted to sensible values for the EVN. Parameters which must be set are mentioned in the docstring at the beginning, e.g., try
> help(evn_aips_tasks.runlwpla)
evn_funcs.py: Other functions used by EVN.py. Mostly provide simplified interaction with functions in evn_aips_tasks.py .
crfuncs.py: Generic functions used by EVN.py. At the moment this is just a couple of filehandling classes to allow better logging of what the pipeline is doing.
The pipeline is driven by an input file. An example can be found here: template.inp
If you want to grab it all in one go, here's a gzipped tar: Pypeline-4-2.tar.gz.
Usage
$ ParselTongue EVN.py template.inp
will run the pipeline using the given input file. A very brief guide to running the pipeline is available: pypeline_public.pdf. A description of the output of the pipeline is available at: http://www.evlbi.org/pipeline/pipe_desc.html. Any comments/questions on the pipeline should be directed to Cormac Reynolds (reynolds@jive.nl)