The Planet Without A Horizon

In Poul Anderson, Flandry's Legacy (New York, 2012) -

- the planet Daedalus in the system of the star Patricius is Earth-like except that:

its plants and animals are humanly inedible;
it rotates in fifteen and a half hours;
pressure and temperature gradients refract light around the globe, as they would on Earth if its radius were thirteen kilometers less;
traveling by riverboat, Diana sees the river and its valley dwindle and merge into a still visible "...shining thread between burnished green darknesses..." (p. 297);
on her left, openings in the wood reveal prairie blurring into haziness;
on her right, "...toylike snowpeaks..." (ibid.);
the setting sun gleams on the ocean around the curve of the planet;
the golden-red sun disc softens and spreads into a step pyramid stretching around what would normally be a horizon, safe to look at;
night is "...a glimmering dusk..." (pp. 297-298);
sunlight becomes a ring, broad and bright, orange and white, in the direction of Patricius, narrower and redder in other directions;
above the ring, the sky ascends through blue and purple to violet;
below is the dark mass of the planet;
Diana stands rapt for hours although regular passengers, used to the sight, go below.