Applied to a form of telescope proposed by Jeaurat in 1778, giving two images, one direct and the other reversed, the coincidence of which might be used to determine transits.
ΚΠ
1807 T. YoungCourse Lect. Nat. Philos. II. 351.
This entry has not yet been fully updated (first published 1896; most recently modified version published online June 2019).