Wikimedi'Òc

US Naval Observatory (Washington, District of Columbia).jpg - KudzuVine

U.S. Observatory, from Robert N. Dennis collection of stereoscopic views.jpg - Dcoetzee

National Observatory (North Front), from Robert N. Dennis collection of stereoscopic views.jpg - Dcoetzee

PSM V82 D358 Hygienic lab of the us public health service in dc.png - Ineuw

Hygienic Lab at the Naval Observatory grounds.jpg - CFCF

MAIN FACADE - Old Naval Observatory, Twenty-Third and E Streets Northwest, Washington, District of Columbia, DC HABS DC,WASH,497A-1.tif - Fæ

INTERIOR, MAIN RECEPTION ROOM - Old Naval Observatory, Twenty-Third and E Streets Northwest, Washington, District of Columbia, DC HABS DC,WASH,497A-2.tif - Fæ

US-D.C.(1891) p155 WASHINGTON, OBSERVATORY.jpg - Metilsteiner

US-D.C.(1891) p161 WASHINGTON, OLD AND NEW NAVAL OBSERVATORY.jpg - Metilsteiner

Old Naval Observatory Lithograph.jpeg - Annehenrysmith

1851 Map of the City of Washington D.jpg - Henrytow

U.S. Naval Observatory, Washington, D.C LCCN2013651881.tif - Fæ

You have heard (...) Sollenburger over the radio (...) time signals from the U.S. Observatory at Wash. Apparatus is one of the most powerful in the world LCCN2016893253.jpg - Fæ

You have heard (...) Sollenburger over the radio (...) time signals from the U.S. Observatory at Wash. Apparatus is one of the most powerful in the world LCCN2016893253.tif - Fæ

U.S. Naval Observatory, Washington, D.C. LCCN2014649279.tif - Fæ

Old Naval Observatory, U.S. Naval Medical School, Washington, D.C (19400464208).jpg - Hiàn (alt)

U.S. Naval Medical School (Old Naval Observatory), Washington, D.C., circa 1908 (19581607532).jpg - Hiàn (alt)

Old Naval Observatory 1936.jpg - John P. Sadowski (NIOSH)

South lawn, U.S. Naval Observatory, Spring 1874. Transit of Venus teams LCCN 93516258.jpg - Maliepa