From the January 2018 issue

The ‘black drop’ effect of sunspots

Can this well-known phenomenon during planetary transits also be observed with sunspots?
By | Published: January 3, 2018 | Last updated on May 18, 2023

The Great American Eclipse has come and gone, and many observers have already shared their impressions of totality with me. And now I’d like to pass those exciting stories on to you.

A sunspot train
Observers using safely filtered binoculars and telescopes enjoyed views of a sunspot “train” with roughly a dozen umbral (dark inner) cores stretching some 140,000 miles (225,000 kilometers) along the Sun’s equator. Another sunspot group near the Sun’s eastern limb joined the train — a pleasant surprise for an eclipse during a solar minimum.

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