Crossword clue: that point of a planet's or comet's orbit which is most distant from the sun, the opposite point being the perihelion.
1 answer found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).
Possible answers
apoapsis in solar orbit; the point in the orbit of a planet or comet that is at the greatest distance from the sun