Relying strongly on photographic methods, the naval observers returned 350 photographic plates in 1874, and 1,380 measurable plates in 1882. The results of the surveys conducted simultaneously from several locations around the world (for each of the two transits) produced a final value of the solar parallax, after adjustments, of 8.809″, with a probable error of 0.0059″, yielding a U.S.-determined Earth-Sun distance of , with a probable error of . The calculated distance was a significant improvement over several previous estimates.
