Our Astronomical Column


    NAKED-EYE SUNSPOTS.— A large circular or ‘regular’ spot has recently been in transit across the sun's disc. This is the second appearance of the spot which began its existence more than a month ago in the previous rotation. Its area measured on July 25 was a little more than 500 millionths of the sun's hemisphere, which is about the limit at which spots become naked-eye objects to keen eyesight. Owing probably to its regular outline, the spot was seen without difficulty by several observers. Particulars of its position are given in the table below, including another spot, No. 6, which was on the disc about a month ago. This spot was seen on one or two days only, partly on account of unfavourable weather, but as its area exceeded that of the more recent spot, it has also been tabulated. Spot No. 6 represents the third and last appearance of a naked-eye group whose earlier history is given in NATURE, May 21, p. 759, and June 18, p. 903.

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    Our Astronomical Column. Nature 120, 201 (1927) doi:10.1038/120201a0

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