Where can I get a Celestial Longbow?

Does no one on this earth know how they come into the game??? I mean type in Celestial bow or Celestial Longbow on google and all you get is auctions, you cant ever find someone who is informing you on where to get it, even guild wiki just says, this item drops in the naphui quarter mission. I want to know how i get it. Do i have to open chests and make it pop out? or do i just have to go through the mission farming the stars, do they come out from the celestial bosses? I want to know please, and any information is greatly appreciated.

Nahpui mission or explorable. Bring 4-5 keys on the mission. Both critters and chests can drop them.

Need to farm the mission, chest, monsters for one or you could always buy one ingame.