Size of Scope

• Brightness is the most important factor in a telescope's design. A larger barrel diameter on the telescope allows more light to shine through the lens. This allows a larger lens or mirror to capture more light, producing a better image. "Aperture" is the correct term for this process. Larger lenses or mirrors grab more light to produce finer detail at maximum resolving power. A 6-inch- or higher-diameter telescope is capable of gathering the needed light for deep-sky viewing.
  
  

Focal Length

• The next factor for consideration is focal length of the telescope. Light in a telescope is brought into focus on a reflective mirror in both types of telescopes that is deflected into the eyepiece. The distance between the focal point and the lens bringing the light rays into focus is equal to focal length. The telescope's focal length divided by the focal length of the eyepiece influences magnification. Longer telescopes produce higher magnification that can show planetary features more clearly.
  
  

Resolution

• The wave nature of light makes a certain amount of blurring unavoidable. Resolution defines how close two stars can be to each other while being viewed as separate clear points of light. Simply put, a larger diameter telescope gives a smaller angular separation, resulting in higher resolution. High-power resolution has some drawbacks pertaining to how much can be seen. As the magnification increases, the field of view decreases along with diminished resolution.
  
  

Tripods

• Movement from the telescope decreases its ability to maintain focus on the image. The base or tripod needs to be solid while allowing horizontal and vertical tracking movements. Altazimuth mounts give both movements in degrees, allowing the astronomer to use charts to locate stars efficiently. With the addition of a drive motor, the astronomer can track the star across the sky. Considering the dynamics of magnification, astronomers note the importance of and depend on a strong, solid mount for the telescope.