How many letters does the top answer for “the constellation that includes the southern celestial pole” have?

The most common answer is octans (6 letters).

Crossword clue: the constellation that includes the southern celestial pole

1 answer found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

octans 6 letters wn-def

the constellation that includes the southern celestial pole