The Pillars of Creation

More than just a pretty picture
The Eagle Nebula image was taken on April 1, 1995, by the Hubble's Wide Field and Planetary Camera 2. Like a digital camera, the WFPC2 uses charge-coupled devices (CCDs) rather than film to record images. CCDs have an array of light-sensitive elements called pixels that turn light falling on them into electrical signals. As we'll see, all the hard work of preparing the final image involves knowing how to interpret each of those signals, removing the "fingerprints" of the camera itself, and turning the signals into measurements of how bright the light is at specific points in the sky.

The WFPC2's field of view is about 1600 by 1600 pixels, which makes it roughly equivalent to a 2.5 megapixel digital camera. While the final image is not true color, it is closer to what your eye would see if you went there than the picture you would get with color film.

Before we begin fashioning the image, I need to reveal why the final picture seems to have had a big bite taken out of its upper-right quadrant.