What appearance do transmissometers resemble?

Transmissometers are important instruments used in aviation to measure the visibility at an airport by assessing the attenuation of light as it passes through the atmosphere. The correct choice indicates that transmissometers resemble "four telescopes looking at each other," which accurately describes their physical structure and function. Transmissometers typically consist of two components: a transmitter and a receiver, which need to be aligned precisely to measure the amount of light transmitted across a determined distance. This setup is akin to telescopes that focus light from one viewpoint to another.

The design of transmissometers involves the positioning of multiple units to ensure accurate measurements across various angles and distances, which can give the appearance of telescopes. Their function relies on the principles of light measurement, just as telescopes measure and interpret light from distant objects.

Understanding this design helps explain how transmissometers work to provide crucial data on visibility conditions critical to flight safety operations at airports.