Assertion: telescope's light | /r/CapableOf | enter the tube
Facets:
Source sentences:
text: The light enters the tube and reflects off a curved mirror (called the primary mirror) at the other end, before bouncing back up the tube to near the top where it reflects off a smaller mirror (called the secondary mirror), which bounces the light out of a hole in the side of the telescope where you attach your eyepiece.
text: The tubes are enclosed so that dust and moisture do not enter the tube, they have fixed optics that do not normally require collimation, and they do not have a central obstruction which reduces the light entering the tube.
text: Light enters the tube, reflects off of the primary mirror at the base and is then focused onto the smaller flat secondary mirror and then finally, into an eyepiece.
text: Light enters the tube, strikes the primary mirror, is reflected to the secondary mirror, and then is reflected again into the eyepiece.