A supplement to the royal astronomer and navigator. [electronic resource] : Supplying (by reduction and equation) accurate astronomical tables; tabuld̆unelmenses, greenovicenses, &c. With a general and accurate solution of the longitude problem, or the effect of parallax and refraction, in distance, truly determined. Compared with the solutions of the same problem, in the nautical almanac and ephemeris, for finding the longitude at sea. By R. Heath, author of the Royal astronomer and navigator.