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Table 1

Observation dates.

2010 June 6, 7
December 6, 7

2011 June 8, 9, 10, 11, 12, 13
December 11, 16

2012 June 10, 11
December 7, 8

2013 June 4, 5
December 8, 9

2014 June 1, 2
December 4, 5

2015 May 29, 30
October 15, 16
December 5, 6

Notes. The angle B0 lies between −1.05° and 0.61° except for October 2015 where B0 = 5.9°.

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