As the name suggests, reflector telescopes use a series of large and small mirrors to bend and reflect and focus light from the stars and other celestial beings.  The simplified diagram below shows how the light eventually reaches the eye.  There are several advantages to buying a reflector telescope.  They are usually cheaper, especially in the higher end telescopes.  There is no chromatic aberration as seen in reflector telescopes since lenses aren’t used.  However, reflector telescopes require quite a bit more maintenance since the mirrors need to be cleaned and aligned and they are more bulky and less easy to transport.