Sunspot positions and sizes for 1825-1867 from the observations by Samuel Heinrich Schwabe

Arlt, R., Leussu, R., Giese, N., Mursula, K. & Usoskin, I. G., 21-Aug-2013, In : Monthly Notices of the Royal Astronomical Society. 433, 4, p. 3165-3172 8 p.

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  • R. Arlt
  • R. Leussu
  • N. Giese
  • K. Mursula
  • I. G. Usoskin

Samuel Heinrich Schwabe made 8486 drawings of the solar disc with sunspots in the period from 1825 November 5 to 1867 December 29. We have measured sunspot sizes and heliographic positions on digitized images of these drawings. A total of about 135 000 measurements of individual sunspots are available in a data base. Positions are accurate to about 5 per cent of the solar radius or to about 3 degrees in heliographic coordinates in the solar-disc centre. Sizes were given in 12 classes as estimated visually with circular cursor shapes on the screen. Most of the drawings show a coordinate grid aligned with the celestial coordinate system. A subset of 1168 drawings have no indication of their orientation. We have used a Bayesian estimator to infer the orientations of the drawings as well as the average heliographic spot positions from a chain of drawings of several days, using the rotation profile of the present Sun. The data base also includes all information available from Schwabe on spotless days.

Original languageEnglish
Pages (from-to)3165-3172
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
Publication statusPublished - 21-Aug-2013



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