This Scioptic Ball plus Telescope is a type of Camera Obscura much like the Solar Microscope of the same era.
The rotating ball mount attached to an outside wall via the mounting plate ("scioptic ball). The ball could be rotated to face any distant object (e.g., the sun) and then locked in place by tightening the retaining ring. On the other side (in a darkened room) the projection telescope was attached. By drawing the tube in or out, an image of the scene outside could be focused on an opposing wall.
The telescope tube consists of a brass main tube (A) covered by a mahogany sheath, and a smaller diameter brass projection tube. This small tube fits inside the main tube using the press fitting (between C and D) to be held in place.
The inner projection tube has three lenses:
B: objective, C: field, D: eyepiece. Lens B & D are fixed to the tube. There is one central aperture inside the tube. All lenses are plano-convex.
| Dia (cm) | f (cm) | Aperture (cm) | |
|
A
|
1.8
|
11
|
0.7
|
|
B
|
1.5
|
3.5
|
NA
|
|
C
|
1.4
|
4.3
|
0.7
|
|
D
|
1.4
|
3.0
|
NA
|