The Gaithersburg Latitude Observatory was one of six observatories — and one of the four original observatories built by 1899Publications of the Astronomical Society of the Pacific, Volume XI, Number 66, 1899, pp 231–239 — tracking the degree of "wobble" occurring on the earth's north-south axis and resultant variation of latitude. The Observatory — along with observatories in Cincinnati, Ohio; Ukiah, California; Mizusawa, Japan; Charjui in Russian Turkestan; and Carloforte, Sardina, Italy — performed in concert to carry out a coordinated program of star observation designed to investigate and calculate the degree of earth "wobble" or latitude variation.National Park Service page about the Observatory
