List of working documents Oleg Smirnov published 3 papers on Calibration and Direction dependent effects (see ALBiUS documents). Main Activities during To correct for direction-dependent effects (like the LOFAR beam) a script has been developed that creates and deconvolves the image using facets. The DDE-correction is calculated for the center of the facet and applied to the entire facet. It works well and produced some good images. However, it is quite slow.
The LOFAR MeasurementSet has been extended with some tables containing all information necessary for the beam calculation.
A LOFAR task force has been started to investigate if direction-dependent effects due to the ionosphere can also be corrected for using the A-propjection method. Support for shapelets as a source model has been added to the LOFAR software. It makes it possible to model a strong source like Cyg-A more compact and accurate. Meetings attended by people involved In October Ger van Diepen attended the XLDB conference in Stanford. In that same trip he visited NRAO in Socorro to work with Sanjay Bhatnagar on CASA.

Problems / Issues None

Red flags - major problems

Forward Look To improve the performance of DDE corrections the A-projection method seems very promising. In May a few people will go to NRAO in Socorro to work with Sanjay Bhatnagar on the implementation of A-projection for LOFAR.

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