( ( Before ( ( the ( Voyager ( 1 spacecraft ) ) ) ( ( flitted ( by ( ( Saturn and ) Titan ) ) ) ( in 1980 ) ) ) ) ( , ( astronomers ( ( knew ( of ( ( ( Titan 's ) atmosphere ) ( because ( of ( ( ( the ( moon 's ) ) ( reddish appearance ) ) ( in ( Earth-bound telescopes ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN Before) (NP (NP (DT the) (NNP Voyager) (CD 1) (NN spacecraft)) (VP (VBN flitted) (PP (IN by) (NP (NNP Saturn) (CC and) (NNP Titan))) (PP (IN in) (NP (CD 1980)))))) (, ,) (NP (NNS astronomers)) (VP (VBD knew) (PP (IN of) (NP (NP (NP (NNP Titan) (POS 's)) (NN atmosphere)) (PP (RB because) (IN of) (NP (NP (NP (DT the) (NN moon) (POS 's)) (JJ reddish) (NN appearance)) (PP (IN in) (NP (JJ Earth-bound) (NNS telescopes)))))))) (. .)))
Before the Voyager 1 spacecraft flitted by Saturn and Titan in 1980, astronomers knew of Titan's atmosphere because of the moon's reddish appearance in Earth-bound telescopes.
(ROOT (S (NP (DT The) (NN voyager) (CD 1) (NN spacecraft)) (VP (VBD visited) (NP (NN saturn)) (PP (IN in) (NP (CD 1980)))) (. .)))