New objectives with two focal distances for night-vision devices
V. G. Volcov, Yu. A. Dobrovolsky, N. F. Koschavtsev,
M. A. Kuskova, G. A. Leonova, T. G. Objedcova
Special Design Office of Night-Vision Devices of State Unitary Enterprise
"RD&P Centre "Orion"", Moscow, Russia
Circuits of designing objectives with admit the availability of field of view in night-vision devices for realizing a search and detection mode and an acquisition mode correspondingly are discussed. Simple circuits of lens and mirror-lens objectives with a stepped changeable focal distance mainly without replacing optical components are offered.