Assertion: reflecting telescope's mirror | /r/HasProperty | flat
Facets:
value: optically
type: DEGREE
value: in nature
type: LOCATION
value: in order to reflect the light
type: PURPOSE
value: at 45 degree angle
type: MANNER
value: almost
type: DEGREE
Source sentences:
text: The fourth and fifth mirrors are (almost) flat, and provide adaptive optics correction for atmospheric distortions (mirror 4), and tip-tilt correction for image stabilisation (mirror 5).
text: That’s the image you want to see out of the eyepiece, so the second mirror used is flat.
text: Sir Isaac Newton preferred a secondary mirror that was flat at 45 degree angle in order to reflect the light to the eyepiece at one side of the telescope near the top of the tube.
text: The secondary mirror comes in the form of that diagonal mirror, which is optically flat in nature.