The most common and most likely answer to this crossword clue is the 9 plus 6 letter word CELESTIAL SPHERE
I've seen this crossword clue in The Daily Telegraph
C
E
L
E
S
T
I
A
L
S
P
H
E
R
E
More clues leading to the result CELESTIAL SPHERE
Buddy explains!
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.