Detection of long-term variability of stars with historical records on astronomy

点击翻译按钮获取中文摘要

In order to detect long-term variability of stars, we investigated surviving historical documents on astronomy and sampled observational data. First, we analysed stellar coordinates (ecliptic and equatorial) to identify and know observational errors. As for star charts, it was difficult to compare with modern observational results because of their non-numerical data and lack of the method of projection and we could not know their accuracy. Although some star catalogues includes misprints, unknown objects could be detected and they might be unknown variable stars or transient objects like supernovae, novae and comets. Second, we compared stellar magnitudes recorded in each documents and detected long-term (about several hundred years) variability.