望远镜前星表星等的准确性
Accuracy of magnitudes in pre-telescopic star catalogues
摘要：
托勒密（公元137年）、苏菲派（公元964年）和第谷·布拉赫（公元1602/27年）星表中的历史星等被转换为约翰逊V等标度，并与希巴谷星表中的现代值进行比较。偏差（或“误差”）的依赖性测试三个不同的观测影响。历史星等和现代星等之间的关系在所有三个星表中都被发现是线性的，就像之前Hearnshaw（1999）在Almagest数据中所显示的那样。在整个数据集中显示出对颜色指数（B-V）的轻微依赖性，而苏菲派和布拉赫的数据也给出了较低顶点高度的恒星的较暗值（表明灭绝）。在这三个星表中，恒星的估计星等都受到其周围环境亮度的影响。在对这三种效应进行校正后，星等误差中剩余的方差可以被认为是望远镜前星等估计的近似精度。最终转换和校正的星等可通过Vizier目录访问工具获得（Ochsenbein，Bauer，& Marcout，2000）。
英文摘要：
Historical star magnitudes from catalogues by Ptolemy (137 AD), as-Sufi (964) and Tycho Brahe (1602/27) are converted to the Johnson V-mag scale and compared to modern day values from the HIPPARCOS catalogue. The deviations (or "errors") are tested for dependencies on three different observational influences. The relation between historical and modern magnitudes is found to be linear in all three catalogues as it had previously been shown for the Almagest data by Hearnshaw (1999). A slight dependency on the colour index (B-V) is shown throughout the data sets and as-Sufi's as well as Brahe's data also give fainter values for stars of lower culmination height (indicating extinction). In all three catalogues, a star's estimated magnitude is influenced by the brightness of its immediate surroundings. After correction for the three effects, the remaining variance within the magnitude errors can be considered as approximate accuracy of the pre-telescopic magnitude estimates. The final converted and corrected magnitudes are available via the Vizier catalogue access tool (Ochsenbein, Bauer, & Marcout, 2000).
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。
