Kasai Trading 50mm f/4 StellaBino-50 Binoculars (Eyepieces Not Included)
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StellaBino-50 is a completely new concept "inverted image" binocular telescope designed specifically for astronomical observations, combining two high-performance 50mm f/4 refractors. The simple structure does not include prisms, yielding much clearer and sharper images than those of ordinary binoculars. The eyepieces are interchangeable, so you can freely choose the magnification and FOV. Filter work is also easily available. Furthermore, since there is no FOV restriction due to the prism size limit, the maximum FOV can be secured with 1.25" eyepieces. A unique design that combines a binoculars-like form that can be easily hand-held with the basic functions and structure required of an astronomical telescope. The 660g lightweight body ensures a comfortable grip in the hands, while also featuring the same specifications as a full-fledged astronomical telescope. This is truly a one-of-a-kind, revolutionary binocular telescope created "only" for astronomy enthusiasts.
Development Concept
Ordinary binoculars are originally designed for terrestrial viewings. Of course, they can also be used for astronomicall observations, but this is merely a "repurposed" use, and therefore "erect images" are always an absolute requirement. However, in order to obtain this erect image, multiple prisms must be incorporated, which inevitably leads to deterioration of image quality and loss of light. Furthermore, the size of the prisms also limits the field of view. For example, in the case of typical 50mm binoculars, it is physically impossible to secure a FOV of over 7° regardless of the magnification. (Of course, there are some models that incorporate huge prisms to achieve an ultra-wide field of view, but they are generally very heavy, large, and extremely expensive.) Furthermore, the fixed magnification is also inconvenient. The eyepieces are also built into the housing, so it is no easy to attach filters.
On the other hand, astronomical telescopes generally produce inverted images, and it is well known that this is to maintain and maximize the performance of the objective lenses. Most astronomers are familiar with inverted images from using telescopes, so the factor of "erect image" is not always necessary as long as it is specialized for astronomical observations. Rather, the benefits (sharpness, wide field of view, brightness, etc.) gained by discarding this factor are far greater. While, the facts that the eyepieces can be switched, the magnification can be easily changed, no FOV restriction, and filters can be freely attached, are all major advantages and indispensable factors for astronomical observations.
Considering these points, the starting point of the development of this device was "to create a pair of binoculars dedicated to astronomical observations that maintains the convenience and operability of binoculars while being equipped with the functions of an astronomical telescope." After several years of conception and multiple prototypes, we were finally able to produce and sell this device.
Optics
High-precision 50mm f/4 doublet achromat objective lenses are designed and manufactured for astronomical use. Full broadband multi-coating achieves high transmission rate as 99.5%. Unlike normal binocular objective lenses, very sharp and clear iamges can be maintained up to a high magnification range of 20-30x. Chromatic aberration is also well corrected, and is suppressed to a level that is almost unnoticeable at magnification ranges within the practical range for deep-sky observaton use. Combined with a simple structure without prisms, clearer image quality that is far superior to that of ordinary 50mm binoculars can be obtained.
Focusers
Butter-smooth rotary helical focusers are equipped. The focusing operation is the same as IF binoculars, familiar for any binocular users.16mm travel and 8mm maximum backfocus can reach the infinity focus with most eyepieces. Low profile fastening screws with metal compression rings for the 1.25" eyepieice adapters can secure good centering retention, holding eyepieces reliably and accurately.
Overall Designs & Features
The unique design combines a binoculars-like form that fits comfortably in hands, and the basic functions and features required of an astronomical telescope, with the assumption that it will be hand-held. 50mm long objective dewcaps reliably block stray lights even when observing in bright surroundings. The inside of the dewcaps and the main tubes are completely anti-reflection matt black painted. In addition, the insides of the tubes are equipped with baffle rings similar to those of ordinary refractors, which eliminate internal reflections and greatly contribute to improving the image contrast. The connection between both the main tubes is an orthodox folding type, so you can adjust the interpupillary distance with the same operation feel as with normal binoculars. Of course, a threaded hole for attaching a tripod adapter is equipped in front of the central axis, and if you use a tripod adapter (optional), it can be mounted on a photographic tripod, etc. Holes for the neck strap (included) are also provided on the left and right sides.
Eccentric-Rings Collimation Function
StellaBino-50 is always shipped with well pre-collimated state, but, as is the fate of binocular telescopes with interchangeable eyepieces, the perfectly collimated state may not always be maintained during actual use. For example, when using heavy and/or large eyepieces, the eyepiece adapter parts may bend slightly, causing a slightly misalignment. In order to make it easy for users to solve this problem, collimation functions are equipped on both the tubes. This structure is generally called an "eccentric-rings collimation mechanism," a method of connecting two slightly eccentric rings and rotating both of them appropriately to adjust the collimation state of both the tubes. Normally it's installed inside the objenctive lens cell, and no easy for users to adjust them. However, in StellaBino-50, these mechanisms are equipped between the main tubes and the eyepiece adapters so that users can access these functions and adjust the collimation state easily whenever necessary.
NOTICE: Each unit of StellaBino-50 is well pre-collimated before shipment, so there is no need for re-adjustment under normal use. Please use this function only when necessary.
General Aptitude
StellaBino-50 is a unique pair of binocular telescopes made "only" for astronomy enthusiasts. The eyepieces can be changed, so you can freely choose the magnification and FOV. You can also use filters freely. There is no FOV limitaton by prisms. Even with two normal eyepieces, the total weight is less than 1kg, so it can be used easily by hand-held. And, the greatest feature is that the simple structure without prisms provides a very bright, clear, and sharp image quality. Please enjoy the splended deep-sky views with your both eyes with eye-opening clarity.
Specifications
- Clear Aperture: 50mm
- Focal Length: 200mm
- Focal Ratio: F4
- Max. Dimensions: 255mm×120mm×57mm
- Weight: 660g
- Focusing Type: IF
- Interpupillary Distance: 58mm - 74mm
- Focusers: Rotary Helical Focusers / 1.25" Eyepiece adapters with metal compression rings
- Other Features: Objective Lens Dewcaps / Threaded Hole for Tripod Adapter
- Eccentric Rings Collimation Functions (both tubes)
- Standard Accesories: Neckstrap
- Image Orientation: Images are both mirror reversed left to right and inverted top down (astronomy only binocular)
| Product Banner Type | new |
|---|---|
| Free Shipping Graphic | Free US Shipping |
| Objective Lens Diameter | 50mm |
| Coatings | Fully Multi-Coated Optics |
| Case | Yes |
| Neckstrap | Yes |
| Objective Lens Cover | Yes |
| Ocular Lens Cover | Yes |
| Inter-Pupillary Distance | 58mm - 74mm |
| Dimensions | 255mm x 120mm x 57mm |
| Weight | 1.46 lb (660g) |
| Hide Found a better Shipped Price on Frontend? | No |
StellaBino-50 is a completely new concept "inverted image" binocular telescope designed specifically for astronomical observations, combining two high-performance 50mm f/4 refractors. The simple structure does not include prisms, yielding much clearer and sharper images than those of ordinary binoculars. The eyepieces are interchangeable, so you can freely choose the magnification and FOV. Filter work is also easily available. Furthermore, since there is no FOV restriction due to the prism size limit, the maximum FOV can be secured with 1.25" eyepieces. A unique design that combines a binoculars-like form that can be easily hand-held with the basic functions and structure required of an astronomical telescope. The 660g lightweight body ensures a comfortable grip in the hands, while also featuring the same specifications as a full-fledged astronomical telescope. This is truly a one-of-a-kind, revolutionary binocular telescope created "only" for astronomy enthusiasts.
Development Concept
Ordinary binoculars are originally designed for terrestrial viewings. Of course, they can also be used for astronomicall observations, but this is merely a "repurposed" use, and therefore "erect images" are always an absolute requirement. However, in order to obtain this erect image, multiple prisms must be incorporated, which inevitably leads to deterioration of image quality and loss of light. Furthermore, the size of the prisms also limits the field of view. For example, in the case of typical 50mm binoculars, it is physically impossible to secure a FOV of over 7° regardless of the magnification. (Of course, there are some models that incorporate huge prisms to achieve an ultra-wide field of view, but they are generally very heavy, large, and extremely expensive.) Furthermore, the fixed magnification is also inconvenient. The eyepieces are also built into the housing, so it is no easy to attach filters.
On the other hand, astronomical telescopes generally produce inverted images, and it is well known that this is to maintain and maximize the performance of the objective lenses. Most astronomers are familiar with inverted images from using telescopes, so the factor of "erect image" is not always necessary as long as it is specialized for astronomical observations. Rather, the benefits (sharpness, wide field of view, brightness, etc.) gained by discarding this factor are far greater. While, the facts that the eyepieces can be switched, the magnification can be easily changed, no FOV restriction, and filters can be freely attached, are all major advantages and indispensable factors for astronomical observations.
Considering these points, the starting point of the development of this device was "to create a pair of binoculars dedicated to astronomical observations that maintains the convenience and operability of binoculars while being equipped with the functions of an astronomical telescope." After several years of conception and multiple prototypes, we were finally able to produce and sell this device.
Optics
High-precision 50mm f/4 doublet achromat objective lenses are designed and manufactured for astronomical use. Full broadband multi-coating achieves high transmission rate as 99.5%. Unlike normal binocular objective lenses, very sharp and clear iamges can be maintained up to a high magnification range of 20-30x. Chromatic aberration is also well corrected, and is suppressed to a level that is almost unnoticeable at magnification ranges within the practical range for deep-sky observaton use. Combined with a simple structure without prisms, clearer image quality that is far superior to that of ordinary 50mm binoculars can be obtained.
Focusers
Butter-smooth rotary helical focusers are equipped. The focusing operation is the same as IF binoculars, familiar for any binocular users.16mm travel and 8mm maximum backfocus can reach the infinity focus with most eyepieces. Low profile fastening screws with metal compression rings for the 1.25" eyepieice adapters can secure good centering retention, holding eyepieces reliably and accurately.
Overall Designs & Features
The unique design combines a binoculars-like form that fits comfortably in hands, and the basic functions and features required of an astronomical telescope, with the assumption that it will be hand-held. 50mm long objective dewcaps reliably block stray lights even when observing in bright surroundings. The inside of the dewcaps and the main tubes are completely anti-reflection matt black painted. In addition, the insides of the tubes are equipped with baffle rings similar to those of ordinary refractors, which eliminate internal reflections and greatly contribute to improving the image contrast. The connection between both the main tubes is an orthodox folding type, so you can adjust the interpupillary distance with the same operation feel as with normal binoculars. Of course, a threaded hole for attaching a tripod adapter is equipped in front of the central axis, and if you use a tripod adapter (optional), it can be mounted on a photographic tripod, etc. Holes for the neck strap (included) are also provided on the left and right sides.
Eccentric-Rings Collimation Function
StellaBino-50 is always shipped with well pre-collimated state, but, as is the fate of binocular telescopes with interchangeable eyepieces, the perfectly collimated state may not always be maintained during actual use. For example, when using heavy and/or large eyepieces, the eyepiece adapter parts may bend slightly, causing a slightly misalignment. In order to make it easy for users to solve this problem, collimation functions are equipped on both the tubes. This structure is generally called an "eccentric-rings collimation mechanism," a method of connecting two slightly eccentric rings and rotating both of them appropriately to adjust the collimation state of both the tubes. Normally it's installed inside the objenctive lens cell, and no easy for users to adjust them. However, in StellaBino-50, these mechanisms are equipped between the main tubes and the eyepiece adapters so that users can access these functions and adjust the collimation state easily whenever necessary.
NOTICE: Each unit of StellaBino-50 is well pre-collimated before shipment, so there is no need for re-adjustment under normal use. Please use this function only when necessary.
General Aptitude
StellaBino-50 is a unique pair of binocular telescopes made "only" for astronomy enthusiasts. The eyepieces can be changed, so you can freely choose the magnification and FOV. You can also use filters freely. There is no FOV limitaton by prisms. Even with two normal eyepieces, the total weight is less than 1kg, so it can be used easily by hand-held. And, the greatest feature is that the simple structure without prisms provides a very bright, clear, and sharp image quality. Please enjoy the splended deep-sky views with your both eyes with eye-opening clarity.
Specifications
- Clear Aperture: 50mm
- Focal Length: 200mm
- Focal Ratio: F4
- Max. Dimensions: 255mm×120mm×57mm
- Weight: 660g
- Focusing Type: IF
- Interpupillary Distance: 58mm - 74mm
- Focusers: Rotary Helical Focusers / 1.25" Eyepiece adapters with metal compression rings
- Other Features: Objective Lens Dewcaps / Threaded Hole for Tripod Adapter
- Eccentric Rings Collimation Functions (both tubes)
- Standard Accesories: Neckstrap
- Image Orientation: Images are both mirror reversed left to right and inverted top down (astronomy only binocular)
| Product Banner Type | new |
|---|---|
| Free Shipping Graphic | Free US Shipping |
| Objective Lens Diameter | 50mm |
| Coatings | Fully Multi-Coated Optics |
| Case | Yes |
| Neckstrap | Yes |
| Objective Lens Cover | Yes |
| Ocular Lens Cover | Yes |
| Inter-Pupillary Distance | 58mm - 74mm |
| Dimensions | 255mm x 120mm x 57mm |
| Weight | 1.46 lb (660g) |
| Hide Found a better Shipped Price on Frontend? | No |
Kasai Trading 50mm f/4 StellaBino-50 Binoculars (Eyepieces Not Included)