This is a copy of the earliest known photograph of the Moon, a daguerreotype taken in 1851. The development of photography was important in astronomy. Still, the human eye can discern more detail than could be captured on a photographic plate. This photograph is typical of Mars' appearance as seen through a large optical telescope on Earth. Here is how Earth would appear with a similar telescope from Mars.
Multispectral imagery can reveal the chemical composition of planetary surfaces.
This information cannot be determined from standard photographs. Radar was first reflected off the surface of Venus in 1961. Since then, techniques have improved to the point that we now can present the surface of a planet as an image or map based on reflected radar signals. A ll objects with a temperature above absolute zero emit some radiation. The amount of microwave energy emitted by a planet is a measure of its temperature.