Simplify the following text for a Grade 6 native English-speaking person.
Original: The `` 40-foot telescope '' proved very cumbersome , however , and most of his observations were done with a smaller 18.5 i 20 f reflector .
Simplified: However , the 40-foot telescope was awkward to use , and most of his observations were done with a smaller 18.5 i 20 f reflector .