When you look through a telescope, planets take on an entirely new appearance.
Literal
Telescope [through-を-通して] see-[when-と], planet [topic-は] entirely new aspect [object-を] present.
を通して ('through, via') is a compound particle using the verb 通す — 'to pass through.' 呈する ('to present, to assume [an appearance]') is a formal verb for displaying a quality. 様相 ('aspect, phase, appearance') is a formal/technical word. An elevated scientific-esthetic observation.