Overview page. Subjects: Astronomy and Astrophysics — Early Modern History (1500 to 1700).
Germanscholar and astronomer. In 1611, with the aid of a telescope he built himself, he became one of several independent discoverers of sunspots (the others included...
Overview page. Subjects: Astronomy and Astrophysics — Medieval and Renaissance History (500 to 1500).
A term used in ecclesiastical lunar tables to calculate the date of Easter. It gives the age of the Moon (i.e. the number of days since New Moon) at the start of each year.
Overview page. Subjects: Early Modern History (1500 to 1700) — Astronomy and Astrophysics.
A prominent open cluster in Taurus, popularly termed the Seven Sisters, and also known as M45. The cluster spans over 1½° of sky and contains about 100 stars, the brightest of which is...