A binary number usually consists of 8 bits (1 byte). The first bit in the sequence represents a 1. The second bit represents a 2. The remaining 6 bits represent 4, 8, 16, 32, 64, and 128 respectively. If all bits are "on" the value of the binary number is the sum of each bit valueQ255. If all bits are "off," the value is 0. A sequence of on, off, on, on, off, off, on, and off represents the numbers 1+0+4+8+0+64+0, or 77. To save classroom time, the binary system has been simplified in this activity by using a 6-bit binary code. The total value of a 6-bit code is 64, or 1+2+4+8+16+32.

After the image of the space object is encoded, the binary bits are transmitted by radio waves to a receiving station on the ground. The photons of light that fall on each of the 2,360,000 pixels are now represented by a data set consisting of 18,880,000 binary bits. They will be converted by a computer to a black and white image of the space object. If a colored image is desired, at least two more images are collected, each one taken through a different colored filter. The data from the three images

Because images collected by the HST and other astronomy spacecraft are digital, astronomers can use computers to manipulate images. This manipulation is roughly analogous to the manipulation of color, brightness, and contrast controls on a television set. The manipulation process is called enhancement and it provides astronomers with a powerful tool for analyzing the light from space objects.

To learn more about the imaging process, refer to the following activities in this guide: Paint By The Number, Colored Shadows, and Color Recognition.

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