I was playing to get an achievement and saw this in the sky. What is it?! : r/outerwilds

Achievements and Trophies - Outer Wilds Guide - IGN

Outer Wilds Achievement Guide 100% PC Achievement Guide

Rigidbody achievement in Outer Wilds

Achievements+ - Displays stock, DLC, and custom mod achievements on a menu screen and shows a popup when you earn one. (by @xen-42)

Easy Sleep. Wake. Repeat. Achievement Trophy Guide - Outer Wilds Echoes of the Eye

Outer Wilds: Echoes of the Eye DLC adds 14 secret achievements

Finally 100% completed Outer Wilds : r/outerwilds

EOTE *minor* spoiler] Artstation has some images from concept art for the DLC. There are 14 achievements in-game, but 15 on the art-station. Any guesses as to what this achievement would've been

After over 100hrs of gameplay, I've finally completed it 100%! : r/ outerwilds

Outer Wilds for Xbox Series - DLC, Achievements, Trophies, Characters, Maps, Story