11 x 8.5 Fresnel Scope



  

 An old wooden loudspeaker cabinet a bit bigger than the lens is used for this scope. The hole for the speaker is used to access the inside for mounting receivers or transmitters. These are attached to an adjustable bracket for centering and focusing. The main bearings are "Dobsonian" like on the 15" scope and they fit into a fork mounting. Rubber feet on the back and one side permit setting it up horizontally or vertically on a flat surface without the mount.


diameter = 265mm x 200mm, focal length = 330mm (f:1.24 x 1.65) 
*field of view with different detector sizes:
Size -- FOV in degrees
1mm     0.17
2mm     0.34
3mm     0.52
4mm     0.69
5mm     0.86
10mm    1.73

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