Imagine (1987)
Arri

Arri Imagine

Memory control for medium & larger sized studios & theatres.
250 or 500 channels, up to 1024 dimmers (512 without optional additional processor card).
3.5" disc backup - up to 1000 cues per disc (1.44Mb).
Up to 28 different cues and effects played back simultaneously.

Imagine 3
From Richard Pilbrow: Stage Lighting Design: The Art, The Craft, The Life
"Designed for mixed rigs of conventional and moving lights, Imagine 3 features 1,536 dimmers with 300, 600 or 1200 channels and up to 1,536 dimmers/parameters."

The 250 channel version was a rebadged ETC Expression.
The 500 channel version was a rebadged ETC Concept

Imagine 250 Systems (partial list):
Norwegian Broadcasting, Oslo
Citizen's Theatre, Glasgow
Key Theatre, Peterborough
Tyne Tees Television, Newcastle
Half Moon Theatre, London
Playlight Hire, Manchester
London Palladium
BBC Belfast
HTV Bristol
Teatro Due, Parma (2 systems)