{"nrhp_refnum":"80003043","name":"Cincinnati Observatory Building","other_names":["See Also:Observatory Historic District"],"category":"building","location":{"address":"Observatory Pl.","address_restricted":false,"city":"Cincinnati","county":"Hamilton County","state":"OH","lat":39.14287033800008,"lon":-84.42263799699998,"geom_source":"nps_gis"},"listed_date":"1980-03-03","is_nhl":true,"nhl_designated_date":"1997-12-09","areas_of_significance":["Architecture"],"significance_levels":["national"],"summary":{"what_it_is":"A two-story brick observatory building on Observatory Place in the Mt. Lookout area of Cincinnati, Hamilton County, Ohio, built 1873-1875 to a design by Samuel Hannaford.","why_significant":"It was built to house the Cincinnati Observatory after the move from Mt. Adams, which had been driven by growing pollution and light problems. It has housed extensive astronomical research since 1873. It is also one of the works by Samuel Hannaford included in a thematic group of his buildings.","narrative":"Built between 1873 and 1875 on a high point in Cincinnati's Mt. Lookout neighborhood, this two-story brick observatory was designed by architect Samuel Hannaford. It replaced the earlier observatory on Mt. Adams, which operated from 1843 to 1872 under the Cincinnati Astronomical Society. Growing pollution and light problems near the city basin prompted the move, and John Kilgour donated a four-acre tract and $10,000 toward the new building. Operation passed to the University of Cincinnati in 1873. The symmetrical building has classical detailing, including a projecting central portico with Corinthian columns and a pediment with a circular window. A ribbed metal dome painted silver sits on a square brick base and replaced an earlier flat observation tower. The telescope pier extends 17 feet below ground, and the interior walls beneath the dome are independent of the building to reduce vibration. A 12-inch telescope bought in 1843 was used until a 16-inch instrument arrived in 1902.","period_of_significance":null,"architect_builder":"Samuel Hannaford (architect); builder unknown","architectural_style":"Greek Revival","criteria":[],"status_note":"Condition listed as excellent inside and out; the 16-inch telescope is no longer in use because glare and pollution make observation difficult.","vacant_flag":null,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:53:09.779219-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_OH/80003043.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/80003043/60abe2c301-800.webp","url_1600":"https://nationalhistoricalregister.com/media/80003043/60abe2c301-1600.webp","licence":"CC BY 2.5","author":"Analogue Kid at en.wikipedia","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Cincinnati_Observatory.JPG\" rel=\"noopener\">Analogue Kid at en.wikipedia</a>, <a href=\"https://creativecommons.org/licenses/by/2.5\" rel=\"license noopener\">CC BY 2.5</a>, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Cincinnati_Observatory.JPG"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71985350","wikipedia":"https://en.wikipedia.org/wiki/Cincinnati_Observatory","wikidata":"https://www.wikidata.org/wiki/Q3348364"},"indexable":true,"url":"https://nationalhistoricalregister.com/ohio/hamilton-county/cincinnati-observatory-building-80003043/"}