Abstract
A GROUP of sunspots, large enough to be seen with the naked eye, has been in transit across the sun's disk (Nov. 3–15), in solar latitude 29° south; the time of central meridian passage was Nov. 9.5. The group, which was of ‘stream’ or ‘bipolar’ type, consisted of a very large circular spot with smaller followers. The leader, with an area of 800 millionths of the sun's hemisphere (800 millionths = nearly 950 million square miles), was the largest single spot observed since February 1931; the maximum total area of the present group was 1,200 millionths of the sun's hemisphere. On the few occasions when the weather permitted spectroscopic observations to be made at Greenwich, the group was not unusually active. Observations made on Nov. 9-11 show another large stream of spots extending in longitude for nearly 80,000 miles in lat. 21° north. The time of central meridian passage was Nov. 13.3. During the last two or three months there has been a marked increase in the sun's general activity, as shown by the increased frequency of spots?mainly of small or moderate size—dark and bright hydrogen and calcium markings on the disk and prominences at the edge of the disk.
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A Naked-Eye Sunspot. Nature 136, 791 (1935). https://doi.org/10.1038/136791a0
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DOI: https://doi.org/10.1038/136791a0