10.1594/PANGAEA.937028Hejda, PavelPavelHejda0000-0002-3576-5754Revallo, MilošMilošRevalloValach, FridrichFridrichValach0000-0003-0547-0055PANGAEA2021DATE/TIMEMagnetic field, declinationMagnetic field, H-componentGeomagnetic observatoryDigitising and processing of historical records1847-07-21T21:20:12/1847-07-22T21:20:12Dataset10.1594/PANGAEA.936921577 data pointstext/tab-separated-valuesCreative Commons Attribution 4.0 InternationalData 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).14.41650.086