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Vixen BT-81S-A Astronomy Binoculars

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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

€1,299.00*

Prices include VAT. Shipping costs not included

Available, delivery time: 2-4 days

Product number: X000002
With Bresser recreational optics, you are always perfectly equipped! We bring you closer to the uniqueness of the moment. 

 
True art of living consists in seeing the wonderful in the everyday. (Pearl S. Buck)

Our wide range includes: binoculars, night vision devices, targeting and precision optics, surveillance cameras, as well as spotting scopes and telescopes. Bresser stands for high quality combined with affordable prices. With our Binocular ABC, Binocular Guide, and an introduction to the history and key features of binoculars, we are happy to assist you before and after your purchase.
  • Binocular ABC

Table of Contents

1.     The History
2.     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
The Binocular - Introduction

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Spotting Scope Guide

Entdecken Sie unsere Ratgeber!

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:

Sky Guides by Bresser

The Sky Guide provides comprehensive information on constellations, planetary positions, and astronomical events – perfect for planning your observations and delving deeper into astronomy.
Visit the guide directly here to make the most of your observations!

Product information "Vixen BT-81S-A Astronomy Binoculars"

Take a look through the new Vixen BT-81S-A binoculars. You will be impressed when you use them to observe gas nebula, star clusters or comets.
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
Angular resolution (arc seconds): 1.43
Batteries included: false
Batteries required: false
Body material: Aluminium
Colour: white
Colour of coating: blue
Compass: false
Diopter setting: true
Dust protection caps: Dust protection caps for front lens and eyepiece holder
ED glass: false
Eyepieces for eyeglass wearers: false
Field of application [Binoculars]: Astronomy, Bird watching & Nature observation, Night, telescopes
Focal length (in mm): 480
Inert gas purged: false
LE Eyepieces: false
Magnification Zoom max.: 50
Material: Aluminium
Material prisms: Glass
Net weight (without access.) (g): 4000
Number of lenses: 2
Optical design: Achromatic Refractor
Power supply unit included: false
Product Family [Binoculars]: Großfernglas
Single eye adjustment: true
Target Group [Telescopes]: Advanced Amateurs, Visual enthusiasts
Total height (mm): 155
Total length (mm): 480
Total width (mm): 190
Tripod adapter thread: true
Type [Binoculars]: Giant Binoculars
Type of coating: Fully multi-coated
Waterproof 8): false
Zoom function: false
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Accessories

Vixen HF2 Fork Mount
Vixen HF2 Fork Mount
The HF2 mount is an azimuthal fork mount for mounting large binoculars. It also requires the X000161 mounting plate for attachment of different binocular types. Not required with the BT126S-A. FEATURES Can be used with: SXG-HAL130, SXG-AL130, APP-TL130 Bearing capacity: 13 kg Weight: 3.4 kg WHAT’S INCLUDED HF2 fork mount Mounting tool

€345.00*
Vixen SXG-HAL130 Aluminum Tripod for GP, SX & AP Mounts
Vixen SXG-HAL130 Aluminum Tripod for GP, SX & AP Mounts
High-quality, stable aluminium tripod for a variety of mounts with 45 mm connections. The aluminium profile ensures firm positioning with a minimum amount of vibration. Suitable for GP2, GPD2, AP, SX, SXP, SXP2 and AXJ mounts or similar with 45 mm connections. FEATURES Robust aluminium tripod without mount Suitable for: GP-, SX- & AP mounts Height-adjustable: 81 - 130 cm Weight: 5.5 kg WHAT’S INCLUDED Aluminium tripod Adjustment pins for GP2, GPD2, AP and SX mounts

€276.00*
Vixen Mounting Plate for large Binoculars in the HF2 Fork Mount
Vixen Mounting Plate for large Binoculars in the HF2 Fork Mount
This plate is designed for large binoculars with 1/4’’ photo thread screws. It is inserted into the HF2 fork mount. The maximum width of the binoculars must be 251mm in order for them to be mounted. FEATURES Mounting plate for large binoculars and BT series Weight: 1 kg WHAT’S INCLUDED Mounting plate for large binoculars 1/4’’ photo thread screw

€165.00*
Vixen SG-L02 Headlamp red-light white-light
Vixen SG-L02 Headlamp red-light white-light
The perfect LED head torch for nighttime observations! Adjusting your eyes to the dark surroundings is very important when making astronomical observations. In dark areas, it is very difficult to use astronomical equipment without a suitable light. With normal lights, however, the light intensity is more important than protecting your eyes against bright light. Using these lights at night makes your pupils contract, which can make it difficult for your eyes to readjust to the darkness. The SG-L01, our first astronomy LED lamp, featured a built-in red LED that provided a solution to this problem. However, the red light did not offer optimal visibility. On our new astronomy LED light, the SG-L02, the LED lights produce warm light to improve visibility. They also ensure that your eyes stay adapted to the dark. The LEDs do not emit light in the sensitive range of 555 nm. The brightness of the white light can be adjusted between 3 and 42 lumen, while the red light can be adjusted between 0.28 and 7.62 lumen. FEATURES Dimmable red light ensures that your eyes stay adapted to the dark Built-in rechargeable battery, charges via USB Waterproof design LED colour can be switched from red to white 0.28 to 7.62 lumen for red light 3 to 42 lumen for white light Dimensions: 41 mm x 33 mm x 30 mm Weight: 29 g DELIVERY CONTENT SG-L02 head torch Strap (size S) Strap (size L) Pocket clip Cable for charging the battery (USB-A plug to USB Micro-B plug)

€69.00*
Vixen SLV 50° Eyepiece 10mm (1.25'')
Vixen SLV 50° Eyepiece 10mm (1.25'')
​The Vixen SLV series are the modern take on the classic Vixen Lanthanum eyepieces. These eyepieces were legendary for their generous eye relief and precise nature, making them a firm favourite with planetary, lunar and double star observers. This 10mm is an excellent eyepiece for medium to higher power on most telescopes, an ideal premium replacement for eyepieces supplied with telescopes, especially good for Planetary observers. The SLV Series of Vixen Eyepieces feature a hexagonal shaped eyepiece body, long 20mm eye relief, and twist up click stop eyecup for adjusting to the most comfortable viewing. The SLV eyepieces feature high grade lanthanum glass, and deliver remarkably clear and high contrast star images to the edge of the field of view. The lenses are fully multicoated for high light transmission.Size 31.7mm/1.25"Apparent FOV 50°Eye relief 20mmWeight 168g (5.92oz)

€142.00*
Vixen SLV 50° Eyepiece 12mm (1.25'')
Vixen SLV 50° Eyepiece 12mm (1.25'')
​The Vixen SLV series are the modern take on the classic Vixen Lanthanum eyepieces. These eyepieces were legendary for their generous eye relief and precise nature, making them a firm favourite with planetary, lunar and double star observers. This 12mm is an excellent eyepiece for medium to higher power on most telescopes, an ideal general purpose eyepiece and major improvement over standard eyepieces. The SLV Series of Vixen Eyepieces feature a hexagonal shaped eyepiece body, long 20mm eye relief, and twist up click stop eyecup for adjusting to the most comfortable viewing. The SLV eyepieces feature high grade lanthanum glass, and deliver remarkably clear and high contrast star images to the edge of the viewing circle. The lenses are fully multicoated for high light transmission.Size 31.7mm/1.25"Apparent FOV 50°Eye relief 20mmWeight 168g (5.92oz)

€142.00*
Vixen SLV 50° Eyepiece 15mm (1.25'')
Vixen SLV 50° Eyepiece 15mm (1.25'')
​The Vixen SLV series are the modern take on the classic Vixen Lanthanum eyepieces. These eyepieces were legendary for their generous eye relief and precise nature, making them a firm favourite with planetary, lunar and double star observers. This 15mm SLV is an excellent eyepiece for medium power for most telescopes, an ideal general purpose eyepiece and provides excellent comfort with long eye relief. The SLV Series of Vixen Eyepieces feature a hexagonal shaped eyepiece body, long 20mm eye relief, and twist up click stop eyecup for adjusting to the most comfortable viewing. The SLV eyepieces feature high grade lanthanum glass, and deliver remarkably clear and high contrast star images to the edge of the viewing circle. The lenses are fully multicoated for high light transmission.Size 31.7mm/1.25"Apparent FOV 50°Eye relief 20mmWeight 168g (5.92oz)

€142.00*
Vixen SLV 50° Eyepiece 20mm (1.25'')
Vixen SLV 50° Eyepiece 20mm (1.25'')
The SLV eyepieces with high-quality lanthanum glass provide remarkably clear and high-contrast star images right up to the edge.The lenses are fully multi-coated for high light transmission.Thanks to the large and comfortable eye relief distance of 20 mm , the eye comfort is maintained, even during longer observing sessions.Even those who wear glasses will have the entire field of view is clearly visible.The click stop eyecups can be tuned up or down to the user's preference.PROPERTIESVery high sharpness and contrast across the entire field of viewComfortable eye relief of 20mmalmost no colour defects due to lanthanum glass1.25" 31.7 mm barrel sizeTurn-down eyecup for people who wear glassesWeight: 155 gWHAT'S INCLUDEDVixen SLV 50 ° eyepieceDust caps

€142.00*
Vixen SLV 50° Eyepiece 25mm (1.25'')
Vixen SLV 50° Eyepiece 25mm (1.25'')
The Vixen SLV eyepieces use high-quality lanthanum glass to deliver remarkably clear and high-contrast star images right up to the edge of the field of view.All lenses are fully multi-coated for high light transmission.Twist up eyecups allow the user to set observing height to their own comfortable specification.  20mm eye relief means that even those who have to wear glasses to observe are able to see right to the edge of the field of view.PROPERTIESVery high sharpness and contrast across the entire field of viewComfortable eye relief of 20mmalmost no chromatism visible due to lanthanum glass31.7 mm receptacle connectionEyecup that can be turned down for glasses wearersWeight: 151gWHAT'S INCLUDEDVixen SLV 50 ° eyepieceDust caps

€142.00*
Vixen APP-TL130 Tripod for AP, GPD & SX Mounts
Vixen APP-TL130 Tripod for AP, GPD & SX Mounts
The APP-TL130 tripod is a lightweight, portable tripod for all standard Vixen mounts with a 45 mm support. Compatible tripods include the Vixen HF2, SX, AP and AXJ mounts. The tripod is adjustable in 3 sections and can be retracted to a very small size. Weighing just 3 kg, it is ideal for astronomy trips. FEATURES Leg section: 3x extendable Maximum extended height: 1296 mm Minimum retracted height: 598.4 mm Material: Aluminium Weight: 3.0 kg Maximum height: 1159 mm (height above the ground) Minimum height: 526 mm (height above the ground) WHAT’S INCLUDED Aluminium tripod Adjustment pins for GP2, GPD2, AP and SX mounts

€209.00*
Vixen Viewfinder 7x50, with illuminated reticule
Vixen Viewfinder 7x50, with illuminated reticule
The Vixen Viewfinder 7x50, with illuminated reticule is an exceptionally high quality optical finder scope, featuring 50 mm Achromatic objective. The internal crosshairs are accurately inscribed and can be illuminated with a battery-powered LED attachment, which can be varied in brightness to the user's requirements. This finder gives a field of view of 7.2° in the night sky. Please note: this finder does not come with a bracket, but will fit numerous standard finder brackets - the X000288 Vixen S 50 mm finder scope short holder, or the X000073 Vixen XY finder scope long holder are particularly recommended. FEATURES Finder with 50 mm achromatic optics Field of view: 7.2° Battery: CR2032 Dimensions: 218x53 mm Weight: 0.375 kg WHAT'S INCLUDED: Viewfinder 7x50, with illuminated reticule

€155.00*
Vixen S 50 mm finder scope holder, short
Vixen S 50 mm finder scope holder, short
​Vixen S 50mm finderscope bracket short, for 50mm findersFor attaching a 50 mm finderscope to the standard Vixen finder shoe, found on many designs of telescopes (not just Vixens)PROPERTIES50mm finderscope bracket shortFor attaching a 50 mm finderscopeCompatible with standard Vixen finder shoeWeight: 195 gWHAT'S INCLUDED50mm finderscope bracket short

€79.00*
Vixen XY finder scope holder, long with spring
Vixen XY finder scope holder, long with spring
​Long bracket for the Vixen 7x50 finder item # 8616.For use on the Vixen finder shoe, used on many telescopesPROPERTIESSize: 50mm × 71mm × 131mmWeight: 170 g / 6.0 ozBuilt-in spring anti-slip mechanismFor Vixen finder holdersWHAT'S INCLUDEDFinder holder with spring

€69.00*
Vixen ASG-CB90 Carbon Tripod
Vixen ASG-CB90 Carbon Tripod
Despite being developed for heavy mounts, the Vixen ASG CB90 carbon tripod is one of the lightest tripods on the market. The ASG CB90 tripod was originally designed for the new AXJ mount. However, it is also ideally suited to the tried-and-tested SX, HF2, AP, GPD2 and GP2 mounts. The hand nuts can be loosened to extend the tripod by one section. The legs of the ASG CB90 tripod can be secured by a reliable screw cap and are equipped with a 2.5 cm interval scale marking. FEATURES 2-section carbon tripodLightweight and portable Stable design with minimal vibrationsDimensions: 545 mm to 900 mm length Connections: 45 mm pin hole Weight: 3.4 kg WHAT’S INCLUDED Carbon tripod

€535.00*
Vixen XY Red Dot Finder Scope II
Vixen XY Red Dot Finder Scope II
Red dot finder for astronomical telescopes. This finder scope provides an easy way to align your telescope with objects in the night sky.The brightness of the dot can be adjusted via a dial.Designed for the Vixen viewfinder shoe FEATURES Weight: 185 g / 6.53 oz Battery: CR2032 Magnification: 1x 1/4" screw hole, adjustable red pointDELIVERY CONTENTLED red dot finderCR2032 battery

€82.00*
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The visual effect of these new 8,5mm 82° LER eyepieces with their long eye-relief and their 82° apparent field is truly a full-immersion experience. Your eye is relaxed, allowing you to easily use the averted vision technique to study faint details across a huge field-of-view. The 82° Series eyepieces come with foldable eyecups make handling and using in the field easy. As experienced astronomers know, eye comfort is critical when trying to observe at the visual limits of the telescope. To keep internal reflections to a minimum, all internal surfaces of the eyepiece barrel are flat black, as well as the edges of the lenses themselves to minimize the scattering of light within the lenses themselves.These eyepieces are the choice for observers wearing glasses - with excellent performance and durability. The patented EMD-coating produces high contrast images and prevents reflexes and ghosting. The argon purging effectively prevents internal fogging, and you don´t have to deal with dirt, fungus or cleansing fluids getting between the lenses. The eyepieces are sealed - this makes sure you will be able to enjoy these eyepieces for many years to come.Comfort, Quality, Value. The Explore Scientific 82° LER Series Most short focal length eyepieces are excellent flat-field multi-element oculars that can transform your visual astronomy experience. These extreme wide field eyepieces are optimized to produce high contrast and high resolution characteristics.SPECIFICATIONSLarge eye distance, large field and great image sharpnessExcellent viewing position for people with glassesExcellent field sharpness even with fast optics82° apparent field of viewArgon-purging prevents internal fogging, the sealing facilitates cleaningPatented EMD-coating to maximize contrastBlackened lens edges to avoid reflexesAll eyepieces of this series are parfocalStainless steel barrel with conical security cutoffDust covers and protective bag includedSCOPE OF DELIVERY82° EyepieceDust coversProtective bag

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Vixen SLV 50° Eyepiece 20mm (1.25'')
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The SLV eyepieces with high-quality lanthanum glass provide remarkably clear and high-contrast star images right up to the edge.The lenses are fully multi-coated for high light transmission.Thanks to the large and comfortable eye relief distance of 20 mm , the eye comfort is maintained, even during longer observing sessions.Even those who wear glasses will have the entire field of view is clearly visible.The click stop eyecups can be tuned up or down to the user's preference.PROPERTIESVery high sharpness and contrast across the entire field of viewComfortable eye relief of 20mmalmost no colour defects due to lanthanum glass1.25" 31.7 mm barrel sizeTurn-down eyecup for people who wear glassesWeight: 155 gWHAT'S INCLUDEDVixen SLV 50 ° eyepieceDust caps

€142.00*
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EXPLORE SCIENTIFIC 82° LER Eyepiece 8,5mm Ar (1,25")
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The visual effect of these new 8,5mm 82° LER eyepieces with their long eye-relief and their 82° apparent field is truly a full-immersion experience. Your eye is relaxed, allowing you to easily use the averted vision technique to study faint details across a huge field-of-view. The 82° Series eyepieces come with foldable eyecups make handling and using in the field easy. As experienced astronomers know, eye comfort is critical when trying to observe at the visual limits of the telescope. To keep internal reflections to a minimum, all internal surfaces of the eyepiece barrel are flat black, as well as the edges of the lenses themselves to minimize the scattering of light within the lenses themselves.These eyepieces are the choice for observers wearing glasses - with excellent performance and durability. The patented EMD-coating produces high contrast images and prevents reflexes and ghosting. The argon purging effectively prevents internal fogging, and you don´t have to deal with dirt, fungus or cleansing fluids getting between the lenses. The eyepieces are sealed - this makes sure you will be able to enjoy these eyepieces for many years to come.Comfort, Quality, Value. The Explore Scientific 82° LER Series Most short focal length eyepieces are excellent flat-field multi-element oculars that can transform your visual astronomy experience. These extreme wide field eyepieces are optimized to produce high contrast and high resolution characteristics.SPECIFICATIONSLarge eye distance, large field and great image sharpnessExcellent viewing position for people with glassesExcellent field sharpness even with fast optics82° apparent field of viewArgon-purging prevents internal fogging, the sealing facilitates cleaningPatented EMD-coating to maximize contrastBlackened lens edges to avoid reflexesAll eyepieces of this series are parfocalStainless steel barrel with conical security cutoffDust covers and protective bag includedSCOPE OF DELIVERY82° EyepieceDust coversProtective bag

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With a new optical design and extremely high resolution, the Vixen BT126SS binoculars provide a considerably more detailed view for astronomical observations. The BT126SS binoculars are characterized by two 126 mm achromatic object lenses and provide 300% more light than the naked eye. 45° angled eyepiece holders offer comfortable, fatigue-free observation. Each eyepiece holder has capacity for 1.25’’ eyepieces. The exchangeable eyepieces allow you to change magnification quickly for the various objects of observation. FEATURES Objective lenses: 126 mm 2-lens achromat Focal length: 625 mm Resolution and limiting magnitude: 0.93 arc seconds, 12.3 light-gathering power 324x Dimensions and weight: 630 x 360 x 200 mm; 10.5 kg Adapter and connections: 31.7 mm clamp WHAT’S INCLUDED Binoculars Carry handle Viewfinder base

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Vixen HF2 Fork Mount
Vixen HF2 Fork Mount
The HF2 mount is an azimuthal fork mount for mounting large binoculars. It also requires the X000161 mounting plate for attachment of different binocular types. Not required with the BT126S-A. FEATURES Can be used with: SXG-HAL130, SXG-AL130, APP-TL130 Bearing capacity: 13 kg Weight: 3.4 kg WHAT’S INCLUDED HF2 fork mount Mounting tool

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