Astronomer is related to Telescope. you are likely to find Lens in/at/on Telescope. you are likely to find Lens in/at/on Camera. 
Soap is a type of Object. Objective is derived from Object. 
Astronomer <--RelatedTo--> Telescope <--AtLocation-- Lens --AtLocation--> Camera 
Soap --IsA--> Object <--DerivedFrom-- Objective 