History of Asher: Observation

Asher: Observation is a lore entry (1st of 12) in the Duress and Egress Lore book, added in Season of Arrivals. It is a lore Triumph; the seal/category is not stated in the sources I could open.

How to complete

Nothing to grind: entries unlock by progressing the Exodus questline. Complete Exodus: Preparation and then Exodus: Evacuation (the Season of Arrivals Exotic quest) and the book entries unlock as you advance. Per Destinypedia the three Asher entries follow his run on Io as the Black Fleet arrives. The quest may no longer be available in the current game, so the unlock path could differ now.

Summary

Asher Mir finishes building a mounted railgun and fires at the Pyramid ship above Io; the projectile stops existing on impact.