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An aquascope (also called bathyscope) is an underwater viewing device. It is used to view the underwater world often from dry land or a boat. It eliminates the water surface glare and allows viewing as far as water clarity and light permit. The underwater viewer can be used for observing reefs, checking boat moorings, secchi disks and other ...
The SZB project includes a 6.7 km-long (4.2 mi) immersed tube which also will be the world's widest immersed tube, carrying eight traffic lanes. [11] Prior to the completion of the Marmaray and HZMB tunnels, the Transbay Tube in San Francisco Bay, completed in 1969, was the world's deepest and longest immersed tube, at 41 metres (135 ft) below ...
Underwater vision is the ability to see objects underwater, and this is significantly affected by several factors. Underwater, objects are less visible because of lower levels of natural illumination caused by rapid attenuation of light with distance passed through the water. They are also blurred by scattering of light between the object and ...
An image intensifier or image intensifier tube is a vacuum tube device for increasing the intensity of available light in an optical system to allow use under low-light conditions, such as at night, to facilitate visual imaging of low-light processes, such as fluorescence of materials in X-rays or gamma rays (X-ray image intensifier), or for conversion of non-visible light sources, such as ...
Large unwieldy lighting systems were problematic to early underwater videography. And last, underwater objects viewed from an airspace with a flat window, such as the eye inside a mask or the camera inside a housing, appear to be about 25% larger than they are. The photographer needs to move farther back to get the subject into the field of view.
The nominal focal length can be multiplied by 1.33× to determine the equivalent angle of view underwater. [36] These were also the first two lenses to be introduced with the Nikonos; the design of the W-Nikkor 35mm is based on the Nikkor 35mm f / 2.5 lens for M39 mount first sold in 1952; it is a symmetric Double-Gauss lens behind an optical ...
Nav finder and underwater compass – basic underwater navigation tools Suunto SK-7 diving compass in aftermarket wrist mount with bungee straps. Diver navigation, termed "underwater navigation" by scuba divers, [1] is a set of techniques—including observing natural features, the use of a compass, and surface observations—that divers use to navigate underwater.
When the bottom measuring point is determined, the height is then measured up to either the optical center or the bottom of the scope tube, on scopes for ring mounts. The difference between these two measuring methods is distance from the optical center to the bottom of the scope tube, and usually corresponds to half of the tube diameter (e.g ...