Kasai Trading 2.3x40 Wide Field Binoculars with 28º True Field of View
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Special Offer: Save $20 when you purchase this item with the WideBino Goggle. Just add both items to your cart and the discount will be automatically applied. Offer valid ONLY if you purchase both items (WideBino28 binoculars and goggles) in the same transaction.
An Immersive Observing Experience
The Kasai WideBino28 binocular is modern version of a Galilean ‘opera glass’ that’s been optimized for astronomical observation. These binoculars deliver up to a 28-degree field of view, allowing you to take in entire constellations in a single field. They help you see about 1.5 magnitudes fainter than is possible with your unaided eyes, which helps make it seem like you’re looking at the night sky with ‘super vision’. The effect is remarkable, especially when using these binoculars in dark sky to explore the star clusters and bright and dark nebulae of the Milky Way. Japanese amateur astronomers have used these binoculars since the early 1990s, and they’re finally available in North America.
Optical Design
Classical and inexpensive Galilean opera glasses and telescopes typically have a very small field of view. These Kasai binoculars deliver a much wider field using very fast objective lenses while managing the lens aberrations with additional optical elements. The 2-group 2-element meniscus objective lenses are matched to 1-group 2-element cylindrical eyepieces to achieve flat fields from edge-to-edge with minimized aberrations. You enjoy pinpoint star images within full field of view. Every surface of the lens element is broadband multi-coated to enhance the transmission, and all the inner walls are thoroughly threaded and blackened to eliminate stray light.
Mechanical Features & Accessories
The body of the Kasai WideBino28 binoculars is made almost entirely of metal. The compact body spans about 123mm and weighs just 255g. Each eyepiece focuses individually. Front and rear dustcovers are standard, and the binoculars include a neckstrap and a soft carrying case with a shoulder strap and a belt loop.
Specifications:
- Clear Aperture: 40mm
- Power: 2.3x
- Field of View: 28-degree
- Max. Dimensions: 123mm x 40mm x 50mm
- Weight: 255g
- Interpupillary Distance: 52mm - 73mm
- Diopter Range to focus infinity: > -6 diopter
- Focusing Mechanism: IF
- Standard Accessories: Front & Rear Dustcovers, Neckstrap, Soft Carrying Case
NOTICE (1): Galilean telescope system has no eye-relief. The best way to see the widest field of view is to "press" your eyes as close as possible to the eyepieces. When wearing eyeglasses, the field of view may be reduced. With very strong eyeglass prescriptions with stronger than -6 diopter, it may not be possible to reach the infinity focus. In such cases, wearing contact lenses is recommended.
NOTICE (2): The field of view of Galilean telescope system varies by the eye pupil diameters of the observer. The full 28-degrees can be obtained when the pupils are opened maximum (usually 7mm). In brighter observing conditions or older observers, a smaller exit pupil will result in a reduced true field of view.
Useful Resources
- Product Review: A Review of the Vixen 2.1x42 Super Wide Constellation and Kasai Trading 2.3x40 Wide Field Binoculars by Brian Ventrudo.
Other Information
- Country of Manufacture: Japan
An Immersive Observing Experience
The Kasai WideBino28 binocular is modern version of a Galilean ‘opera glass’ that’s been optimized for astronomical observation. These binoculars deliver up to a 28-degree field of view, allowing you to take in entire constellations in a single field. They help you see about 1.5 magnitudes fainter than is possible with your unaided eyes, which helps make it seem like you’re looking at the night sky with ‘super vision’. The effect is remarkable, especially when using these binoculars in dark sky to explore the star clusters and bright and dark nebulae of the Milky Way. Japanese amateur astronomers have used these binoculars since the early 1990s, and they’re finally available in North America.
Optical Design
Classical and inexpensive Galilean opera glasses and telescopes typically have a very small field of view. These Kasai binoculars deliver a much wider field using very fast objective lenses while managing the lens aberrations with additional optical elements. The 2-group 2-element meniscus objective lenses are matched to 1-group 2-element cylindrical eyepieces to achieve flat fields from edge-to-edge with minimized aberrations. You enjoy pinpoint star images within full field of view. Every surface of the lens element is broadband multi-coated to enhance the transmission, and all the inner walls are thoroughly threaded and blackened to eliminate stray light.
Mechanical Features & Accessories
The body of the Kasai WideBino28 binoculars is made almost entirely of metal. The compact body spans about 123mm and weighs just 255g. Each eyepiece focuses individually. Front and rear dustcovers are standard, and the binoculars include a neckstrap and a soft carrying case with a shoulder strap and a belt loop.
Specifications:
- Clear Aperture: 40mm
- Power: 2.3x
- Field of View: 28-degree
- Max. Dimensions: 123mm x 40mm x 50mm
- Weight: 255g
- Interpupillary Distance: 52mm - 73mm
- Diopter Range to focus infinity: > -6 diopter
- Focusing Mechanism: IF
- Standard Accessories: Front & Rear Dustcovers, Neckstrap, Soft Carrying Case
NOTICE (1): Galilean telescope system has no eye-relief. The best way to see the widest field of view is to "press" your eyes as close as possible to the eyepieces. When wearing eyeglasses, the field of view may be reduced. With very strong eyeglass prescriptions with stronger than -6 diopter, it may not be possible to reach the infinity focus. In such cases, wearing contact lenses is recommended.
NOTICE (2): The field of view of Galilean telescope system varies by the eye pupil diameters of the observer. The full 28-degrees can be obtained when the pupils are opened maximum (usually 7mm). In brighter observing conditions or older observers, a smaller exit pupil will result in a reduced true field of view.
| Manufacturer | Kasai Trading Co. |
|---|---|
| Objective Lens Diameter | 40mm |
| Magnification | 2.3x |
| Field of View (Angular) | 28° |
| Coatings | Fully Multi-Coated Optics |
| Eye Relief | 8.4mm |
| Case | Yes |
| Neckstrap | Yes |
| Objective Lens Cover | Yes |
| Ocular Lens Cover | Yes |
| Inter-Pupillary Distance | 52mm - 73mm |
| Dimensions | 123mm x 40mm x 50mm |
| Weight | 0.562 lb (255g) |
Special Offer: Save $20 when you purchase this item with the WideBino Goggle. Just add both items to your cart and the discount will be automatically applied. Offer valid ONLY if you purchase both items (WideBino28 binoculars and goggles) in the same transaction.
An Immersive Observing Experience
The Kasai WideBino28 binocular is modern version of a Galilean ‘opera glass’ that’s been optimized for astronomical observation. These binoculars deliver up to a 28-degree field of view, allowing you to take in entire constellations in a single field. They help you see about 1.5 magnitudes fainter than is possible with your unaided eyes, which helps make it seem like you’re looking at the night sky with ‘super vision’. The effect is remarkable, especially when using these binoculars in dark sky to explore the star clusters and bright and dark nebulae of the Milky Way. Japanese amateur astronomers have used these binoculars since the early 1990s, and they’re finally available in North America.
Optical Design
Classical and inexpensive Galilean opera glasses and telescopes typically have a very small field of view. These Kasai binoculars deliver a much wider field using very fast objective lenses while managing the lens aberrations with additional optical elements. The 2-group 2-element meniscus objective lenses are matched to 1-group 2-element cylindrical eyepieces to achieve flat fields from edge-to-edge with minimized aberrations. You enjoy pinpoint star images within full field of view. Every surface of the lens element is broadband multi-coated to enhance the transmission, and all the inner walls are thoroughly threaded and blackened to eliminate stray light.
Mechanical Features & Accessories
The body of the Kasai WideBino28 binoculars is made almost entirely of metal. The compact body spans about 123mm and weighs just 255g. Each eyepiece focuses individually. Front and rear dustcovers are standard, and the binoculars include a neckstrap and a soft carrying case with a shoulder strap and a belt loop.
Specifications:
- Clear Aperture: 40mm
- Power: 2.3x
- Field of View: 28-degree
- Max. Dimensions: 123mm x 40mm x 50mm
- Weight: 255g
- Interpupillary Distance: 52mm - 73mm
- Diopter Range to focus infinity: > -6 diopter
- Focusing Mechanism: IF
- Standard Accessories: Front & Rear Dustcovers, Neckstrap, Soft Carrying Case
NOTICE (1): Galilean telescope system has no eye-relief. The best way to see the widest field of view is to "press" your eyes as close as possible to the eyepieces. When wearing eyeglasses, the field of view may be reduced. With very strong eyeglass prescriptions with stronger than -6 diopter, it may not be possible to reach the infinity focus. In such cases, wearing contact lenses is recommended.
NOTICE (2): The field of view of Galilean telescope system varies by the eye pupil diameters of the observer. The full 28-degrees can be obtained when the pupils are opened maximum (usually 7mm). In brighter observing conditions or older observers, a smaller exit pupil will result in a reduced true field of view.
Useful Resources
- Product Review: A Review of the Vixen 2.1x42 Super Wide Constellation and Kasai Trading 2.3x40 Wide Field Binoculars by Brian Ventrudo.
Other Information
- Country of Manufacture: Japan
| Manufacturer | Kasai Trading Co. |
|---|---|
| Objective Lens Diameter | 40mm |
| Magnification | 2.3x |
| Field of View (Angular) | 28° |
| Coatings | Fully Multi-Coated Optics |
| Eye Relief | 8.4mm |
| Case | Yes |
| Neckstrap | Yes |
| Objective Lens Cover | Yes |
| Ocular Lens Cover | Yes |
| Inter-Pupillary Distance | 52mm - 73mm |
| Dimensions | 123mm x 40mm x 50mm |
| Weight | 0.562 lb (255g) |
Kasai Trading 2.3x40 Wide Field Binoculars with 28º True Field of View