Product Highlights
Vixen BT81S-A binoculars with large 81 mm lenses and option to change the eyepiece for different magnifications, made in Japan
- Binoculars with 80 mm lens diameter
- 31.7 mm (1.25 inch) eyepiece sockets for changeable eyepieces
- Very high light intensity thanks to the large 80 mm lenses
- Dimensions: 480 x 190 x 155 mm / weight: 4,1 kg
- Included: binoculars, carry handle, viewfinder, dew caps
True art of living consists in seeing the wonderful in the everyday. (Pearl S. Buck)
Table of Contents
1. The History2. The Features
2.1 The Key Figures
2.2 The Magnification
2.3 The Objective Diameter
2.4 The Exit Pupil
2.5 The Twilight Factor
2.6 The Brightness
2.7 The Interpupillary Distance
2.8 The Eye Relief (Focal Point of the Eyepiece)
2.9 The Field of View
2.10 The Focus
2.11 The Rubber Armor
3. The Glass
3.1 The Coating
3.2 The Glass Material
3.3 Porro or Roof Prisms
3.4 Achromats
4. Types of Binoculars
4.1 Binocom or Nautic
4.2 Night Glass or Night Vision Device
4.3 Residual Light Amplifiers
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With BRESSER, you can enjoy a smooth introduction to the vast world of astronomy. Our detailed information ("Telescope Guide") provides valuable tips for beginners— but even experienced astronomers can use the information we provide (e.g., tables for the geographical latitude of all major world cities) as a reference.
Here is the table of contents of the comprehensive BRESSER Telescope Guide:
With BRESSER, you can enjoy a smooth introduction to the vast world of astronomy. Our detailed information ("Telescope Guide") provides valuable tips for beginners—but even experienced astronomers can use the information we provide (e.g., tables for the geographical latitude of all major world cities) as a reference.
Here is the table of contents of the comprehensive BRESSER Telescope Guide:
- 2. The View into the Starry Sky
- 2.1 Observing with the Naked Eye
- 2.1.1 Observing Constellations with the Naked Eye
- 2.2 Observing with Binoculars
- 2.2.1 Observing Planets and Moons with Binoculars
- 2.2.2 Observing Deep Sky Objects with Binoculars
- 2.2.3 Every Beginning is Easy
- 2.3 Observing with a Telescope
- 2.4 The Moon
- 2.4.1 The Moon Phases
- 2.4.2 The Far Side of the Moon
- 2.4.3 The Moon Map
- 2.4.4 Maria (Seas)
- 2.4.5 Mare
- 2.4.6 Craters
- 2.4.7 The Ray Craters
- 2.5 Observing the Solar System with a Telescope
- 2.5.1 Where are the Planets?
- 2.5.2 Planet Observation
- 2.5.3 The Position of the Planets Relative to the Sun
- 2.5.4 The Planets Introduce Themselves
- 2.5.5 Deep Sky Observation with a Telescope
- 2.6 Practical Observation Tips and Tricks
- 2.6.2 Tips for Optimal Observation Conditions
- 2.7 The Most Beautiful Objects Throughout the Year
- 4. Telescopes
- 4.1 The Telescope as an Observation Instrument
- 4.2 Optics
- 4.2.1 Refractor (Lens Telescope)
- 4.2.2 Reflector (Mirror Telescope)
- 4.3 Mechanics
- 4.3.1 Altazimuth Mount
- 4.3.2 Equatorial Mount
- 4.3.3 Drive Motors
- 4.4 Accessories
- 4.4.1 Eyepieces
- 4.4.2 Important Tips for Eyepiece Selection
- 4.4.3 Filters
- 4.4.4 Photographic Accessories
- 4.4.5 Other Accessories
- 5.1 Which Telescope for Whom?
- 5.1.1 Deep-Sky Observations
- 5.1.2 Observing Closer Planets
- 5.1.3 The Topic of Portability
- 5.1.4 Price Factor When Buying a Telescope
- 6. Useful Tables
- 6.1 Table for the Geographic Latitude of All Major World Cities
- 6.1.1 Observers in the Northern Hemisphere (N):
- 6.1.2 Observers in the Southern Hemisphere (S):
- 6.2 Lookup Table for Notable Stars
- 6.3 Getting Acquainted with the Universe - or: Distances in Space
The magnesium fluoride coating reduces chromatic aberration and the large aperture of 81 mm ensures a razor-sharp, contrast-rich image.
The BT-81S-A binocular telescope set weighs 4.1 kg, is portable and also exceptionally suited for nature observations.
FEATURES
- Objective lenses: 81 mm 2-lens achromat, multi-coated
- Focal length: 480 mm (f5.9)
- Resolution and limiting magnitude: 1.43 arc seconds; 11.3
- Light-gathering power: 134x
- Dimensions and weight: 480 x 190 x 155 mm; 4.1 kg
- Adapter and connections: 31.7 mm sockets
WHAT’S INCLUDED
- Binoculars 80 mm
- Carry handle
- Viewfinder
- Dew caps
Body material: | Aluminium |
---|---|
Colour: | white |
Colour of coating: | blue |
Dust protection caps: | Dust protection caps for front lens and eyepiece holder |
Focus Group [Telescopes]: | Advanced Amateurs, Visual enthusiasts |
Material: | Aluminium |
Material prisms: | Glass |
Optical design: | Achromatic Refractor |
Product Family [Telescopes]: | Refractor telescope |
Type [Binoculars]: | Giant Binoculars |
Type of coating: | Fully multi-coated |
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