Subject
- Optical Devices[remove]13
- Scientific Equipment13
- Telescopes8
- Astronomy7
- Science7
- Events6
- Exhibitions6
- Great Exhibition, London, 18515
- Astronomical Observatories4
- Lenses4
- Photographic Types and Formats4
- Research Facilities4
- Stereographs4
- Astronomical instruments2
- Geodesic Conference, Nice, 18872
- Cameras1
- Photographic Equipment and Supplies1
- Shelters1
- Tents1