Assertion: sextant's horizon mirror | /r/HasProperty | set by ° -2δ
Facets:
value: from the center of the sextant
type: LOCATION
Source sentences:
text: So in order to the light to drop down a height of h (so that it can reach the telescope), the horizon mirror must be set back by h*cot(60° -2δ) from the center of the sextant.