The most common and most likely answer to this crossword clue is the 10 letter word TELESCOPES
I've seen this crossword clue in The Daily Telegraph
T
E
L
E
S
C
O
P
E
S
Buddy explains!
The straight part
We know that "Contracts/viewers" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case contracts/viewers = telescopes.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does TELESCOPES mean?
TELESCOPES noun- A monocular optical instrument that magnifies distant objects, especially in astronomy.
- Any instrument used in astronomy for observing distant objects (such as a radio telescope).
- To extend or contract in the manner of a telescope.
- To slide or pass one within another, after the manner of the sections of a small telescope or spyglass.
- To come into collision, as railway cars, in such a manner that one runs into another.