Complex sentence: From August 19 to 22 of 1989, Hudson and Steven Ostro observed asteroid 4769 Castalia from the Arecibo Observatory, producing the first direct image of an asteroid.
Split into simpler sentences: From August 19 to 22 of 1989, Hudson and Steven Ostro observed asteroid 4769 Castalia from the Arecibo Observatory. The data collected by them allowed astronomers to produce the first direct image of an asteroid.