Some Binocular info...
Pressure Night Sight Binoculars
30. The binoculars were manufactured by Carl Zeiss, Visnna, and bear the numbers: U.D.F. 7x50
309
170955
31. The measured optical data: Angular field 7° 25' Magnification 7.1 x. Exit pupil 7 mm.
32. The focus is fixed, being set at --).8 dioptre in the centre of the field. 33. The central definition is good provided the observer has normal eyesight and a reasonable amount of accommodation. 34. The definition over the field of view is also up to a good standard.
35. The light at the side of the field is cut down severely by the optical parts.
36. Measured light transmission:
Right limb 67.0 percent. Left Limb 67.2 per cent.
37. Internal surfaces of the lenses are treated with Cryolite or some similar substance.
38. No coloured glasses are embodied in the instrument.
39. The weight of the instrument is
Binocular 12 1/2 lbs. Stand 9 3/4 lbs.
Note. The weight of Pattern 1900C binocular with a rubber jacket is 3 lbs. 13 ozs.
40. A graticule is provided in the right limb. It consists of a vertical line which gradually thickens from the centre to the outside of the field. The line is provided with night illumination by a self-luminous placed in a compartment to the right of the graticule. There is an external lever which controls the illumination from "hell" (Bright" to "dunkel" (Dark). In the bright position the illumination is visible after 2 to 3 minutes' observation in the dark and plainly visible after 10 minutes. In the dark position it is just cut out completely.
41. The inter-ocular adjustment is effected by separating the limbs about the hinge by means of a bar and nuts with right- and left-handed threads. The amount of adjustment provided is from 54 to 74 mm.
Miscellaneous
Luminous Paint
The luminous paint is very good. It is visible immediately the lights are extinguished and so placed as to make it possible to move about without trouble. After a few minutes objects become visible.