Robotic submersibles, sonar, satellites, coring machines, and magnetometers.
Side scan sonar.
radar
RADR
An instrument that makes small, distant objects visible is a telescope. Binoculars and scopes are also used for seeing long distance.
There is no instrument in world which measure how small an object is but instruments measure how large an object is .
It is used to go underwater.
The instrument which is used to measure snowfall is called a snow gauge.
The instrument used to measure the diameter of spherical objects is called calipers.
Diving for underwater exploration
periscope
Binocular
A telescope or binoculars.
telescope
A microscope
Terrestrial telescope
Telescope
sonar is a device used underwater for locating submerged objects and for submarine communication by means of sound waves.
Sound travels through water. Sound reflects from objects with different densities. You can listen for the echoes.
The medical term for an instrument used to view small objects is "microscope." It is commonly used in various medical fields for examining cells, tissues, or microorganisms at a magnified level.
SOund Navigation And Ranging. Its used mainly to detect underwater objects.