Objective Lens
date: label: date made
content: 1939
name: label: maker
content: Fecker, James Walter
notes: label: Description
content: This is a 5-inch aperture objective lens. The “J.W. Fecker / Pittsburgh / 1939 / Apochromat 180o Focus / Correct in Cell” inscription refers to James Walter Fecker, the optical instrument maker in Pittsburgh who made this example for the U.S. Naval Observatory. An apochromat is a lens with minimal chromatic or spherical aberration. Ernst Abbe, Research Director of the Zeiss Optical Works in Jena, introduced the term in the 1880s, in reference to his microscope objectives made with the new Schott optical glass.
label: Location
content: Currently not on view
place: label: place made
content: United States: Pennsylvania, Pittsburgh
topic: label: Subject
content: Science & Scientific Instruments
setName: label: See more items in
content: Medicine and Science: Physical Sciences
creditLine: label: Credit Line
content: U.S. Naval Observatory
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 2005.0172.05
label: catalog number
content: 2005.0172.05
label: accession number
content: 2005.0172
objectType: label: Object Name
content: 5 inch apochromatic lens in brass cell
physicalDescription: label: Measurements
content: overall: 2 1/2 in x 7 in x 7 in; 6.35 cm x 17.78 cm x 17.78 cm
label: Measurements
content: overall: 2 7/8 in x 7 1/8 in x 7 1/8 in; 7.3025 cm x 18.0975 cm x 18.0975 cm