Abstract
STONYHURST DRAWINGS OF SUN-SPOTS AND FACULÆ.— A little more light on the relation of faculæ to spots is contained in a paper communicated by the Rev. Walter Sidgreaves to the Royal Astronomical Society in December 1891. None of the drawings of solar phenomena made at Stonyhurst under the late Father Perry's direction afforded a clear instance of faculæ preceding the birth of a spot. Neither was there any positive evidence of the birth of a spot before the appearance of faculæ; while every spot of importance was attended from the beginning with at least a small surrounding of faculæ. No absolute priority of one or the other could therefore be regarded as proved. During the minimum of 1889, however, Father Sidgreaves observed two cases in which faculæ undoubtedly appeared before any trace of a spot could be detected. “On June 29, a small patch of faculæ was sketched near the eastern limb, in latitude – 40°.5, and in longitude 252°. There was no trace of a spot in the neighbourhood, and neither spot nor faculæ had been seen near the position for years. On the following day a small round spot appeared in latitude – 40°.3, and longitude 252°.2—that is, in the midst of the faculæ, the faculæ on this day being visible only just close round the spot.” A similar development was recorded at the end of July, in latitude – 22°, and longitude 155°. Both the faculæ and spots were new, and clearly distinguished; hence, so far as these observations are concerned, their evidence clearly indicates that the birth of some spots is preceded by the appearance of faculæ.
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Our Astronomical Column.. Nature 45, 261 (1892). https://doi.org/10.1038/045261a0
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DOI: https://doi.org/10.1038/045261a0