naked eye

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the naked eye

Normal vision that has not been enhanced or augmented in any way. Because bacteria are invisible to the naked eye, it was only relatively recently in human history that we even became aware of their existence. The fine print is so tiny, you can barely make it out with the naked eye.
See also: eye, naked
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

*naked eye

the human eye, unassisted by optics, such as a telescope, microscope, or spectacles. (*Typically: appear to ~; look to ~; see with ~; visible to~.) I can't see the bird's markings with the naked eye. The scientist could see nothing in the liquid with the naked eye, but with the aid of a microscope, she identified the bacteria. That's how it appears to the naked eye.
See also: eye, naked
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.

naked eye

Sight unassisted by an instrument such as a microscope or telescope. For example, These insects are too small to be seen with the naked eye. This expression was first recorded in 1664.
See also: eye, naked
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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References in periodicals archive ?
Of these, the hottest that's easily visible to the naked eye is 2nd-magnitude Zeta Puppis, type O5, temperature 42,400 kelvins (76,000[degrees]F).
I observed the Moon in a clear sky from Ma'ale Adummim, east of Jerusalem, with binoculars, but could not see it with the naked eye. Colleagues Joshua Rosenfeld saw it with the naked eye and Tom Rosenfeld with binoculars from Efrat, south of the city.
Instead bigger, deeper glands release liquid through skin holes that are visible to the naked eye. Eltringham is skeptical that the secretions play much of a role in regulating body temperature because a hot hippo just lumbers into water to cool off.
Qatar residence will be able to observe Mars very close to Jupiter over eastern horizon of Qatar sky with naked eye from time rise of Jupiter until sunrise time as Jupiter will rise at 2:24am Doha local time, while sunrise time will be at 6:19am Doha local time, astronomy expert at QCH Dr Beshir Marzouk said.
So I doubt Ganymede can ever be seen with the naked eye, with or without Callisto's help.
This guide is both a visually engaging and a clearly written introduction to reading the night sky with the naked eye, a telescope, or binoculars.
The third brightest luminary 'Venus' will come very close to the moon on September 18 and residents of Qatar will be able to see the two planets together with the naked eye over the eastern horizon of Doha sky from 3:18am until sunrise time.
But what is the total number of stars visible to the naked eye during all seasons and from all latitudes on Earth?
Ranging in diameter from 25 to 45 kilometers, the bodies are the smallest objects ever detected at the fringes of the solar system and are one-billionth as bright as the dimmest celestial objects visible to the naked eye. Theoretical predictions about the origin of short-period comets, which traverse the inner solar system, had led Bernstein and his colleagues to expect to find about 85 of these bodies in the Hubble images.
A new type of barcode is too small to see with the naked eye, yet it holds big promise for biomedical research, law enforcement, and everyday life, say researchers.
Countless skywatchers in the Southern Hemisphere saw Supernova 1987A with the naked eye. It became as bright as magnitude 2.9, despite being 160,000 light-years away in the Large Magellanic Cloud.
Only 30 to 40 kilometers in diameter, the newly discovered bodies are too dim by a factor of 100 million to be discerned by the naked eye. Also complicating their observation is their great distance from Neptune--roughly 60 times as far as Triton, the planet's largest moon.
STAR COLORS--II In the January issue (page 96), I suggested a 10-point scale to use for rating the visual colors of bright stars with the naked eye or binoculars.
Globular dusters are among the oldest groups of stars in the universe, and some of the stars are only one-billionth as bright as the faintest ones visible to the naked eye. It took 8 days of exposure for Hubble cameras to detect the dim white dwarfs.
Anyone who has looked at the galaxy without optical aid has also seen Nu 1[degrees] to its east; the two are pretty much inseparable as far as the naked eye is concerned.