LOFAR calibration challenges

Jan E. Noordam

doi:10.1117/12.544262

28 September 2004 LOFAR calibration challenges

Jan E. Noordam

Proceedings Volume 5489, Ground-based Telescopes; (2004) https://doi.org/10.1117/12.544262
Event: SPIE Astronomical Telescopes + Instrumentation, 2004, Glasgow, United Kingdom

Abstract

The LOw Frequency ARray (LOFAR will observe at 20-200 MHz. At those frequencies, large ionospheric phase variations distort the observed brightness distribution. Fortunately, the imahe may be stabilized for long integrations by using bright radio sources in the sky. The downside is that LOFAR fields will be very crowded, which presents calibration challenges of its own. This is especially true for the bright and extended sources that enter via the relatively high sidelobes of the LOFAR station beams. An extra complication is that these beamshapes vary rather strongly in frequency and time. Altogether, LOFAR will require much more processing than existing radio telescopes, and has only just become possible with the new generation of computers. Even so, new processing techniques like 'peeling' had to be developed to speed things up by several orders of magnitude.

Citation Download Citation

Jan E. Noordam "LOFAR calibration challenges", Proc. SPIE 5489, Ground-based Telescopes, (28 September 2004); https://doi.org/10.1117/12.544262

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