Refracting Telescopes use lenses to gather light and bring the image to the eyepiece. They are fairly maintenance free and generally provide superb images of the moon, planets, star clusters and general sky gazing. They tend to be smaller in aperture than other types so they are not as good for viewing fainter sky objects such as galaxies and nebulae. Good quality refractors tend to be expensive.

• Achromatic - Achromatic refractors are generally inexpensive and suffer from chromatic aberration.  When light passes through a refractor lens, it is bent to reach a focus point at the back of the telescope.  Each wavelength of light is bent by a slightly different amount.  Thus, red, green, and blue wavelengths do not necessarily focus at the exact same position.
  
  
• Apochromatic - Apochromatic refractor lenses are designed so that at least three colors of lights (rather than just two) reach the same focus.  They are designed such that the difference between the primary focus point and the focus point of the remaining colors (such as violet) is extremely small.  In this way, chromatic aberration and secondary color is essentially eliminated. This style is popular for asrto-photography.