Why images trought my 4.5 reflector telescope aren't colered like NASA's?

I agree with Tim. I would also add that those NASA photos are heavily "photoshopped" meaning heavily image processed to bring out the colors. NASA pioneered the art/science of computer image processing starting in the early 60's, and the photoshop application on your computer is an offshoot of that pioneering work.

Well, ..., Over all, unlike photographic fill or a ccd device the Rods and Cones governing how you perceive color can not store data for very long before delivering it to your brain. As a result, you mostly see objects that are far away in space in gray scale.

Also, having a large aperture scope and a younger set of eyes can aid your perception of color. For instance in my 10" SCT I distinctly detect gray scale and blue in the Orion Nebula. One of our club members has a 24" starmaster and when I view the Orion Nebula in it I can detect Olive and Rose coloring. However, for the most part, as others have said, you will mostly view Deep Sky Objects (DSO's) in gray scale. There's nothing wrong with you're scope and the company that sold you the scope quite falsely raised your expectations by labeling it's box (or web advertisement) Hubble like images.

The human eye can't detect colour in dim light. Light needs to be above a certain level to trigger the eye's colour receptors -- otherwise we see everything in shades of grey. I've personally only seen colour in nebulae in telescopes of aperture 18 inches or larger. I see colour in bright objects like stars and planets easily enough, but nothing but grey in nebulae.

[Edit] Sciencenut is wrong about NASA's images being "photoshopped." Colour photography of nebulae began back in the '50s with colour film at Palomar Observatory, long before anybody used computers on images. The colours in most images are completely genuine, not enhanced in any way.

Those pictures are long exposures. It's not (entirely) your telescope, the problem is your eyeball can't collect as much light as a CCD camera or even long exposure film can. Occasionally filters are added to bring out the color as well.

Astrophotography is very different then visual astronomy.

If you have very good eyesight, you might pick out hints of green in some nebulae, for whatever reason, that color is easier to pick out in low light. Remeber, you are bacsically looking at things in the dark, your pupil opens up to let more light in, which sacrifices its ability to interpret color.

Our eyes are not sensitive enough to see colours in low light. NASA images (or any other astrophoto) were taken with long exposure.

The images aren't necessarily photoshopped, but they might be seen through certain kinds of lenses. For example, this common photo from NASA at http://www.nasa.gov/multimedia/imagegallery/image_... was taken through an infrared lens - it's not looking at the visible light spectrum. Read through the descriptions on any of NASA's pictures and it will tell you if there are special considerations taken to get more detail out of the image.

Edited to add: A lot of times, the images are "composite" images - they take pictures looking at different parts of the spectrum, and compile them into one image. As another example, the really cool picture of a spiral galaxy at http://www.nasaimages.org/luna/servlet/detail/NVA2... gives this info in the description: "This color composite was assembled from images taken in blue, visible, and infrared light."

The reason why these images do not look like the HD clarity of NASA's space images is due to the atmospheric distortion that affects the image of cosmic objects.

Because your eye is NOT a camera-- which accumulates the light over a long period of time.