This 81mm astronomy binocular delivers crystal clear, sharp views through its new optical design. Its lightweight body ensures that you can take it to any observing location.
The air-spaced doublet optics in this 81mm are magnesium fluoride coated to help reduce the effects of chromatic aberration.
Mounting the binoculars is a simple process as they come supplied with a Vixen dovetail mounting bar for use with equatorial or altaz mounts. The dovetail bar also has 1/4" thread sockets for use with conventional tripod panheads.
An optional altaz fork mount is available and allows the binoculars to be used on the optional SX-HAL130 or SXG-HAL130 tripods. These provide a stable but lightweight tripod base for this excellent "space binocular".
Note: The BT81S-A is not designed for viewing at high magnification. Use of eyepieces with focal length shorter than 10mm is not recommended. Eyepieces are not supplied as standard with the BT-ED70S-A or BT81S-A.
Images are for demonstration purposes only. Fork mount and tripod are not included.
Model | BT-ED70S-A | BT81S-A |
Objective lens | D=70mm F=400mm ED Apochromatic, multi-coated | D=81mm F=480mm Achromatic, single coating with Mgfl |
Limiting magnitude | 11.0 | 11.3 |
Light gathering power | 100x | 134x |
Dimensions | L400 x W190 x H155 | L480 x W190 x H155mm |
Weight | 4.0kg (8.8lb) | 4.1kg (9lb) |
Visual back | 31.7mm push fit | 31.7mm push fit |
Eyepieces (optional) | SLV and LVW with 31.7mm are recommended excluding LV8-24 Zoom | SLV and LVW with 31.7mm are recommended excluding LV8-24 Zoom |
Accessories included | Finder bracket shoe, carry handle & dew shields | Finder bracket shoe, carry handle & dew shields |
Optional Accessories
78062 HF2 Fork Mount Provides an easy-to-use friction controlled altazimuthal mounting for the Vixen range of astronomy binoculars and other optical devices. The fork mount comes complete with a half-pillar to raise the binoculars to a comfortable viewing height. Fits onto the SXG-HAL130 or SXG-AL130 tripods. (73798 Swing Bracket required for use with BT-ED70S-A and BT81S-A.) Weight: 3.4kg Maximum loading weight: 13kg |
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73798 Swing Bracket for HF2 Mount Required to allow the 78062 Fork Mount to be used with astronomy binoculars and any other optical devices which have a 1/4" screw thread socket. |
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