Accuracy Analysis for Digitized Sunspot Hand-drawing Records of Purple Mountain Observatory

CORC > 紫金山天文台 > 中国科学院紫金山天文台 > 太阳高能及相关物理过程研究团组

	Accuracy Analysis for Digitized Sunspot Hand-drawing Records of Purple Mountain Observatory
	Li Ranyang; Zhou Tuanhui; Ji Kaifan
刊名	Acta Astronomica Sinica
	2016
卷号	57 期号:3 页码:292-301
英文摘要	Sunspot is the most significant feature in solar disk, and the earliest record of the solar activities. It has been systematically observed for about 400 years after the invention of telescopes. The long-term evolution of solar activities, especially the 11 year solar cycle, has been obtained based on these data to a great extent. In recent years, the historical hand-drawing records of sunspot are processed digitally for permanent preserving and computer processing. The hand-drawing records of sunspot will be eventually replaced by the CCD image in the future, therefore it is necessary to evaluate the accuracy of hand-drawing records by comparing them with the CCD image. In this study, 189 digital hand-drawing records of sunspot observed by Purple Mountain Observatory in 2011 are analyzed. The results include: (1) the scanner scale difference between horizontal and vertical directions is 0.2%; (2) the ring of the Sun on the recording paper is not a perfect circle, and the diameter in the east-west direction is 1% shorter than that in the north-south direction; (3) the orientation error of the record paper can reach up to 0.5 degree in scanning. After comparing the sunspot position of hand-drawing records with the simultaneous SDO/HMI (Solar Dynamics Observatory/ Helioseismic and Magnetic Imager) images of continuous spectrum by overlapping method, we find that the accuracy of sunspot position in hand-drawing record is about 7 arcsec. There are roughly 3% of the hand-drawing sunspots whose corresponding sunspots in SDO/HMI images can not be found.
内容类型	期刊论文
源URL	[http://libir.pmo.ac.cn/handle/332002/16877]
专题	紫金山天文台_太阳高能及相关物理过程研究团组
推荐引用方式 GB/T 7714	Li Ranyang,Zhou Tuanhui,Ji Kaifan. Accuracy Analysis for Digitized Sunspot Hand-drawing Records of Purple Mountain Observatory[J]. Acta Astronomica Sinica,2016,57(3):292-301.
APA	Li Ranyang,Zhou Tuanhui,&Ji Kaifan.(2016).Accuracy Analysis for Digitized Sunspot Hand-drawing Records of Purple Mountain Observatory.Acta Astronomica Sinica,57(3),292-301.
MLA	Li Ranyang,et al."Accuracy Analysis for Digitized Sunspot Hand-drawing Records of Purple Mountain Observatory".Acta Astronomica Sinica 57.3(2016):292-301.