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Applying the calibration

At this point the calibration can be considered complete and the source can be separated from the multi-source file and the calibration applied at the same time using the task SPLAT. If multiple sources are specified in the inputs, this task by default will assemble them all together in a single file. Set APARM(7)=1 to disable this. Set APARM(2) to the correlator integration time.

With SPLAT it is also possible to average the data in frequency and in time. The former is done by setting APARM(1)=3 and CHANNELS to the number of consecutive channels that should be averaged together. The output file will have N/CHANNELS channels per IF, where N is the original number of channels per IF. Setting APARM(1)=1 means no averaging of the data. Averaging in time is done by setting SOLINT, in minutes.

For limitations on how much time and frequency averaging is possible refer to Chapter 18 of ``Synthesis Imaging in Radio Astronomy II'' and the imaging limitations section of the EVN web pages. The inputs here average the data into one minute intervals and average every four channels together.

>TASK 'SPLAT'
>SOURCE ''
>DOCALIB 2
>DOBAND 1
>BPVER 1
>APARM(1) 3
>APARM(2) 2
>APARM(7) 1
>CHANNEL 4
>SOLINT 1
>GO

The averaging can be postponed until after the calibration and instead accomplished using the tasks AVSPC and UVAVG.

Finally, before proceeding with mapping and self-calibration of your data, it is probably necessary to perform some final editing. This can be run directly on the single-source files created by SPLAT using tasks such as IBLED and CLIP.


next up previous contents
Next: 8 Further reading Up: 7 Final calibration Previous: Plot of bandpass solution   Contents
Stefanie Muehle 2008-01-28