Enter a clue or pattern or both:
The Clue
First to spot a comet, usually (5 letter answer)
The Answer
NAMER
Tags
Notes
The answer NAMER is seen occasionally, appearing about once every 650 puzzles.
Related Clues
Caller
Christener
Designator
Identifier
Nomenclator
Nominator
Appellation bestower
Finger pointer
Finger-pointer
Title giver
Whistle-blower
One who christens
One who specifies
Cooperative witness, maybe
Definition
NAMER as a noun:
1. a person who gives a name or names; "the owner is usually the namer of a boat"