Hierarchy classification:

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

Anotations

Scope note:

Circular, disc-like attachments placed into telescopes which block the light of the sun to allow for observation of the sun's corona. Historically the term was used for a 19th century instrument that was part telescope and part camera, which allowed for observation of the sun's corona.