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Table 1

Numbers of days available for given years as reported by Scheiner (1630), Scheiner (1651), and Reeves & Van Helden (2010).

Year Days Year Days Year Days

1611 41a 1622 17 1626 169b
1612 31 1623 9 1627 55
1618 7 1624 40 1629 49c
1621 27 1625 343b 1631 12

Total 800



Five days were not analysed because of unreliable positional results.


One day showed only faculae.


Two days were omitted because groups were not drawn completely.

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