Colour

A set of photo-visual color filters is an important observing aid that every planetary astronomer should have. Color filters help overcome image deterioration caused by atmospheric scattering of light, permits separation of light from different levels in a planetary atmosphere, increases hue contrast between areas of differing color, and reduces irradiation within the observer's eye. All of these factors increase the sharpness of details in the atmospheres that are seen on the planets Venus, Mars, Jupiter, Saturn, Uranus and Neptune, and on the surface of the Moon and Mars. Color contrast is important to the planetary observer. Differences in color hues between features on a planet can lead to strange perceptions and confusion about true nature of the planet in study. This is primarily a function of the human eye; however, some optical systems with chromatic aberrations shift certain colors too. To help explain this we must look at some of the properties of the human eye and how we perceive colors. Color Contrast is affected by sharpness of boundaries and by differences in color and shade.