(S (S (S (NP (BASENP (NNS Astronomers)) (SBAR (WHNP (WP who)) (S (VP (VBP own) (NP (BASENP (JJ amateur-class) (NNS telescopes)) (PP (IN with) (NP (BASENP (NNS apertures)) (ADJP (ADJP (RB as) (JJ small)) (PP (IN as) (NP (QP (BASENP (NN 10)) (PP (TO to) (BASENP (NN 12)))) (NNS inches))))))))))) (VP (MD may) (VP (VB be) (ADJP (JJ able) (S (VP (TO to) (VP (VB sight) (BASENP (DT the) (NN ejecta) (NN cloud))))))))) (SBAR (IN as) (S (BASENP (PRP it)) (VP (MD will) (VP (VP (VB have) (NP (BASENP (DT a) (NN period)) (PP (IN of) (BASENP (NN brightness))))) (PP (BASENP (QP (RB about) (NN one)) (NN minute)) (PP (IN after) (BASENP (NN impact))))))))) (PERIOD .))