75864 ED81S
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 astro-photographer.
This 81mm aperture tube is extremely compact and lightweight and comes with the Vixen dual speed focus system as standard.
Light gathering power is 134x and the unit is supplied with tube rings and dovetail mounting plate for quick and easy connection to any Vixen mount.
Includes dovetail plate (not shown)
2011 models are supplied with 75971 50.8mm
Compression Ring Eyepiece Adapter
| 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.
