Term-day magnetic observations from the Prague-Clementinum observatory on 1840-01-23

Data of term-day observations recorded at the Prague-Clementinum observatory in years 1840-1849 are presented. The data were obtained by digitising and processing the original old records published in the yearbooks of this historical observatory. The term-day observations had been agreed for joint measurements by the observatories organised in the Göttingen Magnetic Union (GMU). Data of 120 term-days from January 1840 to December 1849 are published. The observations started at 10 p.m. of Göttingen Mean Time and lasted 24 hours. The interval between observations was 5 minutes (in April, June and July 1842 exceptionally 6 minutes). All time data were transformed into UT, based on the longitude of the Göttingen observatory, which was 9.950°. The time shift is thus 39'48''. The date in the term-day file name indicates the second day which involves substantial part of the observations (22 out of 24 hours).本数据集收录了1840年至1849年间于布拉格克莱门特天文台（Prague-Clementinum Observatory）记录的时段日观测（term-day observations）数据。该数据集通过对该历史天文台年鉴中刊载的原始老旧观测记录进行数字化加工与处理后得到。此类时段日观测是由哥廷根地磁联盟（Göttingen Magnetic Union, GMU）旗下各天文台共同商定开展的联合测量项目。本次公开的数据涵盖1840年1月至1849年12月间共120个时段日的观测结果。观测以哥廷根平时时间（Göttingen Mean Time）的晚间10点为起始时刻，单次观测持续时长为24小时。观测间隔固定为5分钟；1842年4月、6月及7月除外，当时观测间隔调整为6分钟。所有时间数据均基于哥廷根天文台的经度（9.950°）转换为世界时（Universal Time, UT），因此需进行39分48秒的时间偏移校正。时段日观测文件的文件名中所标注的日期，对应包含观测主要时段（24小时中的22小时）的第二个日期。