Crossword clue: a telescope of low power, having a large field of view, used for finding comets.
2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).
Possible answers
A telescope of low power, having a large field of view, used for finding comets.
A telescope of low power, having a large field of view, used for finding comets.