Already in the first few decades after its foundation in 1348, the Charles University in Prague achieved remarkable results in astronomy. One of outstanding persons of this period, professor and rector of Prague University Iohannes Andreae, called Sindel (c. 1375-1456/8), will be briefly introduced. M. Jan Sindel is known as the astronomer in collaboration with whom the clockmaker Nicolaus of Kadan constructed in 1410 the famous astronomical Clock of Prague. The most important Sindel's astronomical treatise "Canones pro eclipsibus Solis et Lune" is added to several manuscripts copies of Albion by Richard of Wallingford (c. 1292-1335), enlarged by M. Johann von Gmunden (1380-1442). This illustrates the connections between Prague and Vienna astronomical schools. In this treatise Sindel describes his version of eclipse instrument, a nomogram for calculation of eclipses of the Moon and Sun, which is a simplification of the more general Wallingford's instrument.