Man on the Moon Achievement in Halo: The Master Chief Collection

Load up a Custom Game on Standoff and change the player trait settings so that all players begin with Sniper Rifles. Once the match begins, position yourself anywhere on the edge of the map near the cliffside base so that the moon is in full view. Now use your Sniper Rifle’s scope to zoom in on the bottom right corner of the moon. Here, you will notice a faint outline of a smiling man, Chris Carney, who was originally a Bungie employee. After focusing on the man's face for a few seconds, the achievement will unlock.