At night more than 1000 visible stars followed a similar course, appearing to rotate in permanent groupings, called constellations, around a fixed point in the sky, which is known as the north celestial pole.
(more than 1000 visible stars; followed; a similar course; T:At night) (the sky; is known; as the north celestial pole) (more than 1000 visible stars; appearing; ) (permanent groupings; called; constellations)
more than 1000 visible stars the sky more than 1000 visible stars permanent groupings
followed is known appearing called
a similar course T:At night
as the north celestial pole
constellations