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Naked Eye Observation

Naked eye observation in astronomy involves observing the night sky without the aid of devices, specifically ones that capture electromagnetic radiation. This includes items such as binoculars and telescopes.

Light Pollution

Light pollution is the presence of excessive artificial light. It also is known as photopollution or luminous pollution.

Consider the effect of the flash from a camera bulb. When you have your picture taken, it becomes difficult to see other objects until the effect of the flash wears off. Light pollution follows the same principal. Detecting stars and planets is much more difficult within a well-lit city area than perhaps out in the countryside where considerably less artificial light is present. Light pollution, in fact, has become such an issue that some telescopes are utilizing light-pollution filters.

Unfortunately, naked eye observation cannot utilize the idea of filters. Even with typical levels of light pollution, humans can only see stars up to 6m. (This measurement is known as the apparent magnitude, which is how bright a star appears from the face of the Earth. The brighter a star is, the lower the apparent magnitude will be.). Ideal atmospheric conditions and the complete absence of light pollution would allow you to see stars up to 8m.

What You Can See

What you can see through naked eye observation is completely dependant on the amount of light pollution, the current atmospheric conditions, and the time of year:

1. stars - you can see anywhere from 200 in bad lighting conditions to 45,000 stars in an ideal dark sky setting
2. nebulae - you can look for the Carina Nebula, or the Orion Nebula (M42). Located near Orion's sword, this will show up as a glowing, hazy patch.
3. galaxies - check out the spiral-shaped Andromeda Galaxy (M31). This galaxy is located within the constellation Andromeda, below the constellation Cassiopeia.
4. planets - Mercury, Venus, Mars, Jupiter, and Saturn are all visible at different times to the trained eye
5. popular items - the Sun, the Earth's moon and the Milky Way are popular items to look for in the night sky

References

Please visit our references page.