Visual spectroscope

Title

Visual spectroscope

Subject

Astronomy
Measuring instrument
Optical instrument
Spectroscope

Description

Wood, brass, glass

Comes with large wooden box with hinged lid (24” x 14” x 8”), 12”tall stand (obs 726), and accessories. It includes a dense flint prism and a reflection diffraction grating. Crosshairs and a precise scale permit the measurement of position of the emission or absorption lines to an accuracy of 6.5 Angstroms with the prism and 3 Angstroms with the diffraction grating. Slow motion arm is damaged, soldering makes attaching to the stand difficult.

In Stebbins’ notebook, “One second size astronomical spectroscope with circle and slow motions, one 1-inch grating, one dense flint prism with minimum deviation, without micrometer. Final bill June 29 $200.”

“The curves are based upon the normal solar spectrum produced by a small grating spectroscope attached to the 12-inch refractor. The center of the sun’s image was kept on the slit of the spectroscope, . . . The spectroscope is a modest affair, being next to the smallest size regularly manufactured by Brashear. The ruled surface of the plane grating is 19 x 25 mm and the objectives of the collimator and view telescope are each of 19 mm aperture and 285 mm focal length.”

Cleaned by J.W. Fecker in 1954.

Creator

John Brashear, Pittsburgh

Source

Stebbins, J. 1907. The color sensibility of selenium cells. Astrophysical Journal. 26, 326, 183-187.

John A. Brashear Company LTD. (1906). Catalogue: Optical, physical, astrophysical and astronomical instruments. John A. Brashear Co. LTD.: Allegheny PA.

Publisher

Astronomy Department, University of Illinois, Urbana, Illinois

Date

1907

Contributor

Michael Svec

Rights

copyright by Michael Svec.

Format

image/jpg

Language

English

Type

physical object

Identifier

University of Illinois Observatory Collection A132
University ID 016671, obs67

Coverage

University of Illinois Observatory, Urbana, Illinois

Files

Brashear visual spectroscope
DSCN0090.JPG
DSCN0087.JPG
DSCN0085.JPG
DSCN0447.JPG

Citation

John Brashear, Pittsburgh, “Visual spectroscope,” University of Illinois Observatory Collection, accessed September 19, 2017, http://uiobservatory.omeka.net/items/show/5.