Distant object is old coin (8)
I believe the answer is:
farthing
'old coin' is the definition.
(I've seen this before)
'distant object' is the wordplay.
'distant' becomes 'far' (synonyms).
'object' becomes 'thing' (an object is a thing or item).
'far'+'thing'='FARTHING'
'is' acts as a link.
(Other definitions for farthing that I've seen before include "Old British coin" , "It used to be one quarter of a penny" , "of negligible value" , "Old piece" , "One quarter of an old penny: measure of land in old England" .)