75864 ED81S
Discontinued September 2014
When the ED81S was introduced, it set a new standard for APO refractors. The combination of better colour correction from the new extra low dispersion (ED) glass and brighter images from its fast f7.7 focal ratio will satisfy the most demanding visual astronomer or astrophotographer. Vixen’s new optical system focuses the full visible spectrum of light to a critical point much more accurately than earlier models resulting in images that are almost free of chromatic aberration in all colours and are sharp edge to edge.
The 60mm visual back on the ED range can accept either an optional extension tube or diagonal to accommodate 50.8mm (2”) eyepieces.
An optional metal carry handle can be attached to the tube rings.
| Model | ED81S |
| Objective lens | 81mm ED apochromatic, multi-coated |
| Focal length (Focal ratio) | 625mm (f7.7) |
| Resolving power, limiting magnitude | 1.43 arc sec., 11.3 |
| Light gathering power | 134x |
| Tube size & weight | (OD) 90mm x (L) 583mm, 2.3kg (5.1lb) |
| Finderscope | Optional |
| Adapter thread / visual back | 60mm on scope body. 42mm for T-mount, 31.7mm push-fit, 50.8mm* push fit on optional flip mirror |
| Accessories included | Dovetail adapter, tube rings & dual speed focuser |
| Photography** | Prime focus, eyepiece projection and afocal imaging |
*A 50.8mm mirror diagonal or a 50.8mm extension tube is needed to use a 50.8mm eyepiece. **Optional photographic accessories are needed.
