Assertion: sextant's mirror | /r/HasProperty | parallel
Facets:
Source sentences:
text: Double Reflectivity depends upon the principle that the angle of incidence of a ray of light equals its angle of reflection (angles 1, and 2 in blue above when the mirrors are parallel).
text: 1) Trim the mirrors (see trimming the mirrors below) 2) Turn the CD until the mirrors are parallel.