Telescope Size and its Effect on Images

Another size-related effect is that larger telescopes look through wider patches of the atmosphere which usu- 

At least three general, overlapping categories related to telescope size may be defined  

Telescopes small enough to be portable. Sizes usually less than 1 m. 

Mounted telescopes with monolithic primary optics. Sizes presently range up to 6 m for existing telescopes, with many 8 m telescopes either planned or under construction. Virtually all ground-based telescopes used by professional astronomers are in this category. 

Very large telescopes with multielement primary optics. Proposed sizes range up to 25 m for ground-based telescopes. Only a few multielement telescopes have actually been built. 

---