Detectors and Imaging
The front line detectors for almost all astronomers are their own eyes. For many, especially when using smaller telescopes, these are also the only detectors. The eye, or more particularly vision, which is the result of the eye and brain acting in concert, is, however, a very complex phenomenon, and some knowledge of its peculiarities is essential for the observer. Thus reference has already been made in Chap. 8 to averted vision, the effect of high contrasts (known as irradiation) and the combination of sub-resolution features (Martian canals). The structure of the whole eye (Fig. 9.1) is well known from school, and need not be considered further here. It is the structure of the eye’s detector, the retina, which is of importance.