In 1970 Hardy's first SF cover appeared on the then-new magazine Vision of Tomorrow. Another cover followed, then he was commissioned to paint a different planet each month, together with a one-page article about it which he wrote himself. This is the first one: Mercury.
Painted in gouache in 1972 for Challenge of the Stars with Patrick Moore, this shows the glare of the Sun eclipsed by a large rock – the only way to see its Zodiacal Light (a swarm of dust left behind from the origin of the Solar System). The blue Earth and Moon can be seen as a bright double star.
Mercury & Sun
Mercury and the Sun, three times bigger than we see it, from space. Mercury is cratered and very Moonlike, at least superficially. Digital, from Futures: 50 Years in Space.