The term deep sky object is popular among astronomers to describe those faint patches among the stars that can be found only with optical assistance. The equipment needed to take pictures of deep sky objects is within the reach of dedicated amateur astronomers. In such low light
levels there strictly is no color, but there is a natural desire to make these images look as they might appear if our vision were sensitive enough to perceive color. This is a component of esthetic presentation, and the use of color for this subject is extremely useful in education.CCD
imaging equipment, because of its linearity, allows us to record and measure the spectral energy in a specific band determined by a filter placed in front of the sensor. By making several such recordings through red, green, and blue filters, a full color composite can be created. Of particular
interest to astrophotographers are emission nebulas, whose spectra frequently comprise the dominant lines of hydrogen and ionized oxygen. These are present in a scene along with the wideband blackbody emissions of stars. Stars that shine into clouds of interstellar dust show yet other characteristic
color. What is the representation of the recorded channels to portray a colorimetrically correct picture of these deep sky objects? This is the topic that will be addressed in this paper.