| 摘要 |
<p>The objective returns rays in the direction of their incidence. It consists of a convergent entry lens (L1), a primary mirror (L2), a secondary mirror (L3) and an enlarging lens (L4) between the primary mirror and the secondary in a non reflecting central zone. There is also a convergent lens (L5) behind the primary mirror, in the central non reflecting zone. The primary mirror is a concave lens with a front refracting face (a) and a rear reflecting one (b). The secondary mirror is a concave lens with a front refracting face (c) and a rear reflecting one (d).</p> |
