Observer

An observer is a quest item in Fallout 3.

Location
It is given to the Lone Wanderer by Moira Brown during the quest Wasteland Survival Guide.

Related quest
Wasteland Survival Guide - Moira Brown asks the player character to place the observer in one of the 3 batches of mirelurk eggs located at the Anchorage Memorial to observe their behavior. One must then travel to the Memorial to do so.