Color Filters

Astronomers place filters in their telescopes to isolate one color of light from an object. By measuring the amount of light measured through different filters, they can quantify the color of an object. For stars, they can then tell its temperature. Filters also allow you to more easily distinguish between different types of objects in an image.

For instance, looking through which of the filters you've been provided with allows the text on this screen to stand out the most against the background?  Why do you suppose that is?

 Below is a typical filter "wheel" used in photometry. The wheel is placed in front of the camera sensor so that light from the telescope must pass through one of the circular openings in the wheel. The Empty slot allows all of the light to pass on to the camera. The Clear UV filter blocks all light of shorter wavelengths and passes longer wavelengths of the visible spectrum. The remaining three filters pass the color of light they are named for while blocking the other colors.