- Out of stock at supplier, enquire with store
Available now instead
The Vixen BT81S-A Astronomical Binoculars is out of stock at every supplier we deal with. These are in stock or available to order now.
The Vixen BT81S-A is a large astronomical binocular telescope with 81 mm objectives, made for wide views of the Moon, star clusters, nebulae and comets. Compared with the earlier BT80-A it is about 100 mm shorter thanks to a shorter focal length, 40 mm lower and roughly 900 g lighter, with a revised optical design for better image quality.
The eyepiece section is angled at 45°, so you can observe high in the sky - even near the zenith - in a comfortable position. It takes standard 31.7 mm eyepieces (sold separately), and Vixen recommends pairing it with the HF2 fork mount and the rigid SXG-HAL130 tripod for stability.
At a Glance
| 81 mmObjective | 480 mm (f/5.9)Focal length | 134× the unaided eyeLight gathering |
| 11.3Limiting magnitude | 31.7 mm, 45° angledEyepiece fitting | 4100 gWeight |
Key Features
- 45° angled eyepieces – Comfortable observing at any elevation, including straight overhead.
- 31.7 mm eyepiece fitting – Choose your own eyepieces to set magnification and field.
- Compact redesign – Around 100 mm shorter and 900 g lighter than the BT80-A it replaces.
- Finder base included – Ready for an optional red-dot or optical finder.
- Stable mounting system – Designed to sit on Vixen's HF2 fork mount and SXG-HAL130 tripod.
Best For
- Sweeping star clusters and the Milky Way under dark country skies
- Viewing the Moon and bright comets
- Long observing sessions on a fork mount from a backyard or farm
Specifications
| General | |
|---|---|
| Brand | Vixen |
| Part number | VX14304 |
| Optics | |
| Objective lens | 81 mm / achromatic, single-coated (MgF2) |
| Focal length | 480 mm (f/5.9) |
| Resolving power | 1.43 arc seconds |
| Limiting magnitude | 11.3 |
| Light-gathering power | 134× the unaided eye |
| Eyepiece angle | 45° |
| Eyepiece barrel size | 31.7 mm |
| Body | |
| Dimensions | 480 × 190 × 155 mm |
| Weight | 4100 g |
| Finder | Finder base included (finder sold separately) |
| Eyepieces | Sold separately |
| Photography | Not supported |
| Solar observation | Not supported |
Frequently Asked Questions
Are eyepieces included?
No. Vixen sells the eyepieces separately (31.7 mm barrel, two needed).
What mount and tripod do I need?
Vixen recommends its HF2 free-stop fork mount with the SXG-HAL130 tripod; neither is included.
How do the Vixen BT models compare?
BT-ED70S-A: 70 mm SD objectives, 400 mm focal length, 4000 g. BT81S-A: 81 mm achromat, 480 mm, 4100 g. BT126SS-A: 126 mm achromat, 625 mm, 10,500 g, 324× the light of the eye.
Can I use it to look at the Sun or take photos?
No. Vixen lists solar observation and photography as not supported.
Australian stock with local warranty and service through the Australian distributor. Questions about this model? Get in touch and we will help.
