Gould was one of the first to use the telegraph to determine longitudes. This he did by simultaneously finding the Sun's direction at two sites, one for which the longitude was known, and comparing the findings to compute the unknown longitude. From 1852 until 1867 he was in charge of the longitude department of the U.S. Coast Survey. In 1866 he made use of the Atlantic cable to establish the difference of longitude between the observatories at Greenwich, Eng., and Washington, D.C.

After publishing a treatise in 1859 on the positions and proper motions (the motions of stars with respect to the other stars) of the circumpolar stars that were used as standards by the U.S. Coast Survey, he was invited by the government of Argentina to found and direct the National Observatory at Córdoba in 1868. Two years later he began his observations and in 1874 completed his Uranometria Argentina (1879; “An Argentine Uranometry”). In 1884 he published a zone catalog, covering 73,160 stars in a particular portion of the sky, and one year later a general catalog of 32,448 stars in the Southern Hemisphere.