Most pictures of galaxies that you see, such as the beautiful images from the Hubble Space Telescope, are optical images. These are made using telescopes which detect light in the same wavelength range that our eyes see. However, scientists can design telescopes which use different parts of the electromagnetic spectrum, such as shorter-wavelength ultraviolet light or longer-wavelength infrared and radio emission.
First off, the general word astronomy is the study of outer space and everything in it to the last detail. In order to study all that mass it has to be broken down into separate categories. These are just a few types of space astronomy. Some of the different types include planetary, solar, stellar, and galactic. Understanding the different types of astronomy might give you a basic knowledge of how things are broken down in the universe.