Eyepiece Micrometer


The U.S. Naval Observatory acquired an 8.5-inch transit circle by made by Pistor & Martins in 1865, and used it to determine positions of standard and miscellaneous stars, the Sun and Moon, and major and minor planets. This filar micrometer was used at the eye-end of that instrument. It has horizontal and vertical screws and spider lines, as well as a set of Rogers levers so that several measurements can be made at one time and recorded later. These levers were designed by Joseph Addison Rogers (1840-1917), a young man who graduated from Yale in 1860, received a Ph.B. in civil engineering from Yale in 1861, and then went to work at the Naval Observatory.

Ref: “Modification of the Micrometer Head, devised by Mr. Joseph A. Rogers, Aid U.S. Naval Observatory,” Astronomische Nachrichten 63 (1865): 77-78.

Date Made: 1865

Location: Currently not on view

Subject: Science & Scientific Instruments

See more items in: Medicine and Science: Physical Sciences


Exhibition Location:

Data Source: National Museum of American History

Id Number: PH.327702Accession Number: 283654Catalog Number: 327702

Object Name: eyepiece micrometer

Measurements: overall: museum housing: 5 1/2 in x 8 in x 7 3/4 in; 13.97 cm x 20.32 cm x 19.685 cm

Guid: http://n2t.net/ark:/65665/ng49ca746aa-423f-704b-e053-15f76fa0b4fa

Record Id: nmah_1183843

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