Advantages and Disadvantages of Refracting Telescopes:
Advantages:
1. Superior revolving power per inch of aperture
2. Superior performance in inferior conditions - image steadier
3. Not reflections or interruption of light path
4. Near permanent optical alignment - minimum maintanance
5. Long focal ratios can mean use of longer focus, simplier, eyepieces
Disadvantages:
1. Very high initial cost relative to reflector
2. A certain amount of secondary spectrum (chromatic aberration) unavoidable (reflector completely free of this)
The colours cannot focus at one point
3. Long focal ratios can mean that the instrument is cumbersome