averted vision

Astronomers often practice a technique known as averted vision to see very faint things.

There is a name, however, for the technique you describe: "averted vision".

Under typical dark sky conditions Uranus (magnitude +5.8) can be seen as well with averted vision.

Additionally, M74 may be more easily seen when using averted vision when the eyes are fully dark adapted.

The smaller reflection nebula component requires a larger instrument to be seen, along with the use of averted vision.

Astronomers call this averted vision, he said.

It has been hard not to think that an averted vision of sorts has been at work in the space program.

The nearby 7th magnitude star on the west hinders observation, but one can view the nebula using averted vision.

Averted vision is a technique for viewing faint objects which uses peripheral vision.

If it is particularly dark and a particularly faint celestial object is of interest, averted vision may be helpful.

Ability in this area, which requires the use of averted vision, varies substantially from observer to observer, with both youth and experience being beneficial.

The Triangulum Galaxy (M33) is a difficult averted vision object and only visible at all if it is higher than 50 in the sky.

It ranges from easily visible by direct vision in dark skies to a difficult averted vision object in rural or suburban skies.

One way of changing the direction perceived is to use averted vision and mentally look for an arm going behind instead of in front, then carefully move the eyes back.

However, it can be viewed well in the peripheral vision (averted vision), which causes it to "blink" in and out of view as the observer's eye wanders.

Averted vision works because there are no rods (cells which detect dim light in black and white) in the fovea: a small area in the center of the eye.

Hence, in order to observe dim stars, astronomers use averted vision, looking out of the side of their eyes where the density of rods is greater, and hence dim objects are more easily visible.

For the first time Anne and Gilbert saw the shadow cast by that brilliant star of evening, that faint, mysterious shadow, never seen save when there is white snow to reveal it, and then only with averted vision, vanishing when you gaze at it directly.

Because cone cells are all that exist directly in the fovea, astronomers have to look at stars through the "corner of their eyes" (averted vision) where rods also exist, and where the light is sufficient to stimulate cells, allowing an individual to observe faint objects.