A	Camera lens
B	Binoculars
C	Cassegrain reflector
D	Schmidt reflector
E	Naked eye
F	Twin catadioptric Newtonian binocular
G	Coronagraph
H	Hyperboloid astro-camera
I	Multiple-Mirror Telescope
J	Jones-Bird telescope
K	Klevtsov-Cassegrain
L	Newtonian
M	Maksutov
N	Monocular 1x
O	Opera glass
P	Prime focus of a reflector
q	"small telescopes" with aperture in range 4-10 inches
Q	"for observations with the largest telescopes"
r	"small telescopes and finders" with aperture not exceeding 4 inches
R	Refractor
S	Schmidt-Newtonian
T	Schmidt-Cassegrain
U	Coude focus of a reflector
V	Volosov-Newtonian
W	Wright-Schmidt
Y	Ritchey-Chretien
