Sunspot positions, areas, and group tilt angles for 1611-1631 from observations by Christoph Scheiner
Sunspot positions, areas, and group tilt angles for 1611-1631 from observations by Christoph Scheiner
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DOI：
10.1051/0004-6361/201629000
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发表时间：
2016-11-01
影响因子：
6.5
通讯作者：
Spada, F.
中科院分区：
文献类型：
--
作者：
Arlt, R.;Pavai, V. Senthamizh;Spada, F.
目标。克里斯托夫·沙伊纳 (Christoph Scheiner) 出版的书《Rosa Ursina sive solis》和《Prodromus pro sole mobili》中印刷的观测数字图像，以及沙伊纳写给马库斯·韦尔瑟 (Marcus Welser) 的信中的绘图，均经过分析，以获得有关蒙德极小期之前出现的太阳黑子的位置和大小的信息。在大多数情况下，给定的黄道方向用于建立绘图的日照坐标系。位置和尺寸是在屏幕上手动测量的。非常早期的图画没有表明它们的方向。在某些情况下使用使用相邻天的共同点的旋转匹配，而在其他情况下，图像与天顶地平线坐标系对齐的假设似乎是最可能的结果。总共测量到了 8167 个太阳黑子。沙伊纳的观测获得了太阳黑子纬度随时间的分布（蝴蝶图）。 1611年的观测结果非常不准确，1612年的图纸至少表明了它们的方向，而1618年和1631年的其余部分光点位置具有良好到非常好的精度。我们还计算了 1618-1631 年间观察到的明显双极太阳黑子群的 697 个倾斜角。我们发现近 4 度的平均倾斜角度与 20 世纪的值没有显着差异。
Aims. Digital images of observations printed in the books Rosa Ursina sive solis and Prodromus pro sole mobili by Christoph Scheiner, as well as the drawings from Scheiner's letters to Marcus Welser, are analysed to obtain information on the positions and sizes of sunspots that appeared before the Maunder minimum.Methods. In most cases, the given orientation of the ecliptic is used to set up the heliographic coordinate system for the drawings. Positions and sizes are measured manually on screen. Very early drawings have no indication of their orientation. A rotational matching using common spots of adjacent days is used in some cases, while in other cases, the assumption that images were aligned with a zenith-horizon coordinate system appeared to be the most probable.Results. In total, 8167 sunspots were measured. A distribution of sunspot latitudes versus time (butterfly diagram) is obtained for Scheiner's observations. The observations of 1611 are very inaccurate, the drawings of 1612 have at least an indication of their orientation, while the remaining part of the spot positions from 1618 1631 have good to very good accuracy. We also computed 697 tilt angles of apparently bipolar sunspot groups observed in the period 1618-1631. We find that the average tilt angle of nearly 4 degrees is not significantly different from 20th-century values.