Manufacturer:

C. Ridell Company  Search this

Materials:

HAZMAT: possible cadmium; Cast iron, anodized aluminum, optics, electrical components, light bulbs.

Dimensions:

3-D: 114.3 × 61 × 94cm (3 ft. 9 in. × 2 ft. × 3 ft. 1 in.)

3-D (Table): 114.3 × 71.1 × 71.1cm, 29.9kg (3 ft. 9 in. × 2 ft. 4 in. × 2 ft. 4 in., 66lb.)

3-D (Storage Dimensions Table & Microscope Parts): 152.4 × 121.9 × 91.4cm, 65.8kg (5 × 4 × 3 ft., 145lb.)

3-D (Bulb, Microscope Parts): 14 × 3.8cm (5 1/2 × 1 1/2 in.)

3-D (Black Lenses (2), Microscope Parts): 7.6 × 2.5cm (3 × 1 in.)

3-D (Brass Lens, Microscope Parts): 5.7 × 2.5cm (2 1/4 in. × 1 in.)

3-D (Black Fragment, Microscope Parts): 15.2 × 3.2cm (6 in. × 1 1/4 in.)

3-D (Plug, Microscope Parts): 20.3 × 17.8 × 2.5cm (8 × 7 × 1 in.)

3-D (Paper Filter, Miscroscope Parts): 11.4cm (4 1/2 in.)

3-D (Wires, Microscope Parts): 10.2 × 10.2cm (4 × 4 in.)

3-D (Switch Box, Microscope Parts): 21.6 × 12.7 × 8.3cm (8 1/2 × 5 × 3 1/4 in.)

3-D (Variable Speed Control, Microscope Parts): 17.8 × 17.8 × 10.2cm (7 × 7 × 4 in.)

Type:

EQUIPMENT-Scientific Devices

Country of Origin:

United States of America

Summary:

This is a blink stereo comparator microscope manufactured about 1960 by the C. Ridell Company of Williams Bay, Wisconsin for the U. S. Naval Observatory. It is typical of a class of discovery devices used in photographic astronomy from the late 19th through the 20th centuries to detect variable stars and asteroids, and high-proper motion stars. Two photographs of the same part of the sky were placed side by side in parallel microscopes that through a set of mirrors combined the two images, allowing the observer to switch rapidly between the two aligned scenes. Anything in the field of view that changes becomes visible through a shifting or pulsating image. In this design, the usual viewing eyepiece has been replaced with a system that projects images of the plates onto a circular screen. This reduced the fatigue of this tedious operation, which sometimes could take decades. It was transferred to NASM by the U S Naval Observatory in 1996.

Credit Line:

Transferred from the U.S. Naval Observatory, Washington, DC

Inventory Number:

A19960303000

Restrictions & Rights:

Usage conditions apply

See more items in:

National Air and Space Museum Collection

Data Source:

National Air and Space Museum

GUID:

http://n2t.net/ark:/65665/nv9ac0882c7-a731-4a08-a38d-def5adc2b684

EDAN-URL:

edanmdm:nasm_A19960303000