OTA · 1991–2011
Takahashi FS-102
Key specifications
| Aperture | 102 mm |
|---|---|
| Focal length | 820 mm |
| Focal ratio | f/8.1 |
| Optical design | Fluorite Doublet |
About
102 mm f/8.1 air-spaced fluorite doublet apochromat (Fraunhofer, front fluorite), 820 mm focal length. A widely admired 4-inch visual refractor of the FS era; superseded by the FC-100D line.