Sentence:  I was surprised by […] the unusually tall windows, […] through which long telescopes were once turned on eclipses of the sun and the moon, on the intersections of the orbits of the stars with the line of the meridian, on the <WSD>Leonid</WSD> meteorite showers and the long-tailed comets flying through space. 
Meaning of the word marked with <WSD> tags:  Each of a shower of meteorites which fall from the area of sky around the constellation Leo in November.