Tzar rages about astronomer (9)
I believe the answer is:
stargazer
'astronomer' is the definition.
(I know that astronomer can be written as stargazer)
'tzar rages about' is the wordplay.
'about' indicates an anagram.
'tzar'+'rages'='tzarrages'
'tzarrages' with letters rearranged gives 'STARGAZER'.
(Other definitions for stargazer that I've seen before include "Looker-up at night" , "Astronomer, or dreamer" , "Observer of the sky at night" , "One looks up" , "Astronomer or astrologer" .)