- This instrument isinscribed "Young & Sons, Philadelphia 5867" and dates from around 1875. The mark on the telescope-"Patented July 28th 1874"-refers to the patent (#153,494) granted to J. W. Nystrom and Alfred Young. It describes a method of regulating the focus of a telescope by moving the erecting lenses back and forth while keeping the object glass and cross hairs at a fixed distance from one another.
- Currently not on view
- Object Name
- wye level
- Young & Sons
- place made
- United States: Pennsylvania, Philadelphia
- telescope: 19 in; 48.26 cm
- overall: 10 in x 21 in x 5 7/8 in; 25.4 cm x 53.34 cm x 14.9225 cm
- ID Number
- accession number
- catalog number
- Data Source
- National Museum of American History
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