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arXiv 2001.02939astro-ph.SR
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Kodaikanal天文台的太阳黑子图：半球太阳黑子数和面积测量的代表性结果

Sunspot Drawings at Kodaikanal Observatory: A Representative Results on Hemispheric Sunspot Numbers and Area Measurements

Ravindra B., Kumaravel Pichamani, Selvendran R., Joyce Samuel, Praveen Kumar, Nancy Jassoria, Navneeth R. S

备注：
11 pages, 10 figures, accepted for publication in Astrophysics and space science
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摘要：

太阳黑子出现的周期性的重要性在19世纪中期得到了很好的认识。世界各地的几个天文台以图画的形式记录了太阳黑子，并将它们安全地保存下来。在Kodaikanal天文台（KO），太阳黑子观测始于1905年。在那些时候，观察记录在照相板上，在实验室中对这些板进行显影后，在Stonyhurst网格上绘制相同的图形。在这些被称为{ \em太阳图}的图中，太阳盘上的不同特征，例如，太阳黑子、斑、暗条、暗斑等都被清楚地识别出来，并用不同的颜色进行视觉标记。我们收集了111年的太阳黑子图，跨越了10个太阳周期。这些太阳黑子图被仔细拼接成合订本，每6个月一卷。这些图纸保存在Kodaikanal图书馆，供科学使用和分析。本文简要介绍了用方格网绘制太阳黑子图的过程、计算黑子数的方法和测量黑子面积的方法。我们分别收集了北半球和南半球的数据。从收集的数据，我们计算太阳黑子的数量和面积，并将其与皇家格林威治天文台（RGO）和太阳黑子指数和长期太阳观测（SILSO）的数据进行比较。结果表明，太阳黑子数的测量值被低估了约40%。用RGO月平均总黑子数数据对KO月平均太阳黑子数数据进行归一化处理。

英文摘要：

The importance of the periodicity in sunspot appearance was well recognized by the mid of 19th century. Several observatories around the globe have made the record of sunspots in the form of drawings and preserved them safely for posterity. At the Kodaikanal Observatory (KO), the sunspot observations have begun in 1905. In those times observations were recorded on photographic plates and after the development of those plates in the laboratory, the drawings of the same were made on the Stonyhurst grids. In these drawings, called {\em sun charts}, different features on the sun's disk, e.g., sunspots, plages, filaments, prominences, etc. were clearly identified and visually marked with different colors. We have collected 111 years of sunspot drawing spanning over 10 solar cycles. These sunspot drawings were carefully stitched to make bound volumes, each for every 6-months. The drawings are kept at the Kodaikanal library for scientific use and analysis. In this article, we describe briefly the process of drawing, methods of counting sunspot numbers and measurement of sunspot area using square grids. We have collected the data for the Northern and Southern hemispheres separately. From the collected data, we compute the sunspot number and area and compare it with Royal Greenwich Observatory (RGO) and Sunspot Index and Long-term Solar Observations (SILSO) data. The results show that the measurement of the sunspot number is underestimated by about 40\%. The KO monthly averaged sunspot number data of both hemispheres is normalized with the RGO monthly averaged total sunspot number data.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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