nähtavast

Nähtavast is an Estonian term used in the context of perception and optics to refer to the portion of the electromagnetic spectrum that can be perceived by the human eye. In scientific and educational writing, nä htavast is commonly encountered in phrases such as nähtavast spektrist or nähtavast valgusest, indicating material or phenomena within the visible range.

The concept of nähtavast (visible) is distinguished from non‑visible ranges such as ultraviolet and infrared light. In practical terms, the visible spectrum is the part of light that enables human vision and is often cited as approximately 380 to 740 nanometers in wavelength, though exact boundaries can vary with age, lighting, and measurement conditions. This distinction is central in fields like photography, astronomy, vision science, and color theory, where visible light is separated from non‑visible radiation for analysis and application.

In Estonian usage, nähtavast is frequently encountered in academic texts, textbooks, and pedagogical materials to describe what can be seen without instruments. It also appears in everyday language when contrasting what is visible to the naked eye with what remains hidden or detectable only with tools.

See also: Visible spectrum, Ultraviolet, Infrared, Vision science, Optics.