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Fig. 9

image

What ancient observers possibly saw. Left: contemporary white-light image of the Sun captured by HMI from space. Middle: a simulation of what could observers see assuming 2′′ seeing and 2′′ resolution telescope. Right: the same for 2′′ seeing and 5′′ telescope. Obviously, the large spots remain perfectly observable, however the small ones are blurred and may be easily missed by the observers, especially when observing in low-contrast conditions (e.g. in a free space).

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