Jupiter Cantab Limited was a Cambridge

Cambridge

The city of Cambridge is a university town and the administrative centre of the county of Cambridgeshire, England. It lies in East Anglia about north of London. Cambridge is at the heart of the high-technology centre known as Silicon Fen – a play on Silicon Valley and the fens surrounding the...

 based home computer

Home computer

Home computers were a class of microcomputers entering the market in 1977, and becoming increasingly common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a single nontechnical user...

 company. Its main product was the 1983 Forth based Jupiter Ace

Jupiter ACE

The Jupiter Ace was a British home computer of the early 1980s, produced by a company, set up for the purpose, named Jupiter Cantab. The Ace differed from other microcomputers of the time in that it used FORTH instead of the more common BASIC.- Introduction :...

.

The company was founded in 1982 by two ex-Sinclair Research staffers, Richard Altwasser

Richard Altwasser

Richard Francis Altwasser is a British engineer and inventor, responsible for the hardware design of the ZX Spectrum.- Biography :Altwasser graduated at Trinity College, Cambridge, with a degree in engineering in June 1978. He was hired by Sinclair Research in September 1980...

 and Steven Vickers

Steve Vickers (academia)

Steve Vickers is the author of the Sinclair ZX Spectrum home computer ROM firmware. He is currently a Senior Lecturer at the University of Birmingham, UK.- Education :...

. Their machine was, externally, remarkably similar to the ZX Spectrum

ZX Spectrum

The ZX Spectrum is an 8-bit personal home computer released in the United Kingdom in 1982 by Sinclair Research Ltd...

, with a copycat rubber keyboard. It also used the same Z80

Zilog Z80

The Zilog Z80 is an 8-bit microprocessor designed by Zilog and sold from July 1976 onwards. It was widely used both in desktop and embedded computer designs as well as for military purposes...

 processor. However, the Ace's video output was limited to monochrome, unlike the Spectrum's 8 colour capability.

The £90 Ace was a flop in both the UK and US markets: the Forth language, although considered powerful, was not as popular or accessible as the already well-established BASIC language featured in competing microcomputers. In the US it was sold as the Ace 4000.

The company went bankrupt in November 1983 and its assets were sold to Boldfield Computing Ltd in 1984. The remaining hardware was sold-off into 1985.