بوتار ِ سینوس ِ آبه butâr-e sinus-e Abbe
*Fr.: condition des sinus d'Abbe*
In → *geometric optics*, a condition for eliminating
→ *spherical aberration* and → *coma*
in an → *optical system*. It is expressed by
the relationship:
sin *u'*/*U'* = sin *u*/*U*,
where *u* and *U* are the angles, relative to the
→ *optical axis*,
of any two rays as they leave the object, and *u'* and *U'* are the
angles of the same rays where they reach the image plane.
A system which satisfies the sine condition is called
→ *aplanatic*. Named after Ernst Karl Abbe (1840-1905), a German physicist;
→ *sine*; → *condition*. |