| 释义 |
> as lemmasRamsden's ghost Ramsden's ghost n. now historical and rare an apparatus consisting of one or more convex lenses which projects the image of a contrasting object onto a plumb line, or projects the image of the plumb line onto a wire, in order to align a telescope which is mounted in a transit circle, mural circle, quadrant, or sector; (also) the image produced by this apparatus.< |