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The Sun doing a flyby

Submitter: Sarod Yatawatta and Michiel Brentjens
Description: Around mid June this year, the Sun was almost in conjunction with Taurus A. Due to the clever thinking of the observatory staff, an observation was scheduled during this time using the LOFAR highband system. The observation used 4 Tiles (4x4 dipoles) and 20 dipoles. Observation was done on 2 consecutive days, for a duration of 12 hours each, when the Sun was up. On each day, data was collected covering the frequency range 125 MHz to 175 MHz.

The above sequence of images shows the Sun passing by Taurus A on both days. There is also a combined image where the data from both days are used. The Sun travels from right to left, so it is easy to identify the time sequence. The calibration of this observation was especially challenging due to the movement of the Sun, and also due to its extended nature. However, this problem was solved using AIPS++ measures, which uses the JPL ephemeris, and also using a variable disk model. Note that although the Sun moves significantly from day 1 to day 2, there is NO movement in Taurus A, verifying the accuracy of the calibration.
Copyright: ASTRON
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