Peter Haars (1940–2005) was born in Germany but moved to Norway in the 1960s where he worked as a graphic designer, art director and illustrator. He also wrote fiction and created Prokon (1971), a one-off publication that looks like a designer’s take on underground comics. Most of the covers that turn up when you search for his work are science fiction, and all painted in that bold airbrush style that was common in the 1970s. Documentation is scarce, unfortunately, ISFDB only lists two titles, so I’ve no idea about the dates, but the Lanterne SF imprint was active throughout the decade.