Collimator lens and meridian mark
Title
Collimator lens and meridian mark
Subject
Astronomy
Optical instrument
Optical instrument
Description
Metal, glass
Measures 8 ¼ x 6 x 11 ½ inches, lens is 1.7” in diameter.
Director G.W. Myers articulated the need for a Meridian or mire Mark in a March 6, 1897 letter to university President Draper. “Mire mark and Collimator for 3-inch Combined and Transit and Zenith Telescope.” The collimator was mounted in the north window of the east-central transit room on a brick pier, cased in wood above the level of the floor, with a wooden box as a cover. The wood reduces the impact of the brick’s radiant heating. The meridian mark was located on a distant pier north of the building at the focal point of the collimator lens. The Meridian mark was removed with the construction of Smith Hall (1917), the pier for the collimator was removed during the 1956 expansion of the Observatory. At the Elgin Watch Company Observatory (Illinois), there was also a 3-inch Warner & Swasey transit with a meridian mark 100 feet to the north consisting of a metal plate with a hole three thousandth of an inch in diameter serving as an artificial star.
Measures 8 ¼ x 6 x 11 ½ inches, lens is 1.7” in diameter.
Director G.W. Myers articulated the need for a Meridian or mire Mark in a March 6, 1897 letter to university President Draper. “Mire mark and Collimator for 3-inch Combined and Transit and Zenith Telescope.” The collimator was mounted in the north window of the east-central transit room on a brick pier, cased in wood above the level of the floor, with a wooden box as a cover. The wood reduces the impact of the brick’s radiant heating. The meridian mark was located on a distant pier north of the building at the focal point of the collimator lens. The Meridian mark was removed with the construction of Smith Hall (1917), the pier for the collimator was removed during the 1956 expansion of the Observatory. At the Elgin Watch Company Observatory (Illinois), there was also a 3-inch Warner & Swasey transit with a meridian mark 100 feet to the north consisting of a metal plate with a hole three thousandth of an inch in diameter serving as an artificial star.
Creator
Warner & Swasey Company
Source
Payne, W.W. (1927 January) Elgin Observatory. Popular Astronomy. 35 (1) 1-9.
Publisher
Astronomy Department, University of Illinois, Urbana, Illinois
Date
1897
Contributor
Michael Svec
Rights
Copyright by Michael Svec
Format
image/jpg
Language
English
Type
physical object
Identifier
University of Illinois Observatory Collection A136
Coverage
University of Illinois Observatory, Urbana, Illinois
Files
Collection
Citation
Warner & Swasey Company, “Collimator lens and meridian mark,” University of Illinois Observatory Collection, accessed April 19, 2024, https://uiobservatory.omeka.net/items/show/18.