Eyes

From Slackerpedia Galactica

A pair of mostly redundant organs in animals that allow them to detect visual wavelengths of electromagnetic radiation.

Amateur astronomers often refer to the eye as the Mark I Eyeball or 1x7 binoculars, proving that not just professional astronomers like to sound like geeks.

DO NOT LOOK AT THE SUN WITH A MARK I EYEBALL, WITH OR WITHOUT A TELESCOPE!!!

The Slacker Astronomy founder, Aaron, has a retinal burn on his left eye from staring at a solar eclipse in 4th grade. He used a pinhole camera but instead of looking at the projection, he looked through the hole!

The average human can see to magnitude 6-6.5 under dark skies, but human eyes vary a great deal in their quality. Stephen James O'Meara has legendary good eyesight. Eyesight deteriorates with age. This can be slowed by exercise, vitamins, UV-protecting sunglasses, etc. and exacerbated by poor diet, smoking, etc. The usual stuff about being smart and healthy applies here. The eye's pupil opens wider when exposed to the longer wavelength of red light compared to other wavelengths. This is why astronomers use red lights when observing visually. It takes 15-30 minutes for the eyes to fully adapt to darkness. So if you attend a star party and open a car door or turn on a white flashlight, expect to be lynched.

Amateur astronomers also like to make use of the averted vision technique when observing faint objects. However, sometimes they have to use averted imagination.