Caplan J
Appl Opt. 1972 Sep 1;11(9):1978-85. doi: 10.1364/AO.11.001978.
A photoelectric stellar spectrophotometer, with 0.3-A resolution, for use near Halpha (6563 A) is described. A Fabry-Perot etalon and an echelle grating are simultaneously pressure-scanned. The Fabry-Perot can be bypassed and the grating system used alone to obtain narrow-band (4.89-A) Halpha indices, in which case the pressure system allows the necessary radial velocity corrections to be made conveniently.
描述了一种用于Hα（6563埃）附近、分辨率为0.3埃的光电恒星分光光度计。法布里-珀罗标准具和阶梯光栅同时进行压力扫描。法布里-珀罗标准具可以旁路，单独使用光栅系统以获得窄带（4.89埃）的Hα指数，在这种情况下，压力系统允许方便地进行必要的径向速度校正。
