H & K lines of Calcium in Sunspots

Made:
1870-1959
part of archive:
John Evershed Archive

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Science Museum Group Collection
© The Board of Trustees of the Science Museum

Science Museum Group Collection
© The Board of Trustees of the Science Museum

Science Museum Group Collection
© The Board of Trustees of the Science Museum

Caption reads - 'H & K lines of Calcium in Sunspots - The upper spectrum shows the reversals of the calcium lines in a group of Sunspots. The lower spectrum shows a single Sunspot photographed with the slit of the Spectrograph placed radial to the Sun's image. In this position of the slit the fine lines are always found to be slightly bent where they cross the spot band, and the calcium lines are also slightly twisted, but in the opposite direction. These displacements of the lines indicate motion in the line of sight, and it has been found that the low level vapours represented by the fine lines, flow radically outward from the spot centre, whilst the high level calcium vapour flows inwards towards the spot centre. Photographed at the Kodaikanal Observatory.'

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Measurements:
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Identifier:
EVER/A/1/E119

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