Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Furnishings and Equipment (hierarchy name)
4. Measuring Devices (hierarchy name)
5. measuring devices (instruments)
6. [measuring devices for extent]
7. distance measuring devices
8. angle measuring devices
9. vertical angle measuring devices

Additional parents:

1. top of the aat hierarchies
2. Objects Facet
3. Furnishings and Equipment
4. Tools and Equipment
5. equipment
6. equipment by profession or discipline
7. equipment for science and technology
8. scientific instruments
9. astronomical instruments

Anotations

Scope note:

Reflecting navigational instruments used for measuring the altitude of celestial bodies and having an arc of 1/8 of a circle, but due to their reflecting properties can measure up to 90 degrees; invented in the 1730s and used into the 19th century when superseded by sextants.