( ( ( These instruments ) ( ( ( are ( two telescopes ) ) , ) ( with ( ( the objectives ) ( ( spaced prehaps ) ( 18 apart ) ) ) ) ) ) ( , ( each ( ( directed ( to ( ( an eyepiece ) ( via ( ( mirrors or ) prisms ) ) ) ) ) . ) ) ) )
(ROOT (S (S (NP (DT These) (NNS instruments)) (VP (VBP are) (NP (CD two) (NNS telescopes)) (, ,) (PP (IN with) (NP (NP (DT the) (NNS objectives)) (VP (VBN spaced) (NP (NNS prehaps)) (ADVP (NP (CD 18)) (RB apart))))))) (, ,) (NP (DT each)) (VP (VBD directed) (PP (TO to) (NP (NP (DT an) (NN eyepiece)) (PP (IN via) (NP (NNS mirrors) (CC or) (NNS prisms)))))) (. .)))
These instruments are two telescopes, with the objectives spaced prehaps 18 apart, each directed to an eyepiece via mirrors or prisms.
(ROOT (S (NP (DT A) (NN telescope)) (VP (VBZ is) (VP (VBN used) (S (VP (TO to) (VP (VB make) (S (NP (NP (NNS objects)) (PP (IN in) (NP (NN space)))) (VP (VB appear) (ADVP (RBR closer))))))))) (. .)))
A telescope is used to make objects in space appear closer.