Probe the Starry Skies with 3D-Like Depth of Field
Orion BT70 Premium Binocular Telescope in stock
#09547
$649.95
Oversize
Orion BT70 Premium Binocular Telescope
- A true binocular telescope with optical performance on a par with fine astronomical instruments
- Multicoated 70mm air-spaced achromatic lenses and BAK-4 prisms deliver sharp, high-contrast images
- 90° eyepiece angle makes tripod-mounted observing more comfortable
- All-metal body design is built to last. One-year limited warranty
Orion loves binocular stargazing, and our BT70 makes it even more rewarding. It's a true binocular telescope, with optical quality and features you'd expect of a fine astronomical instrument. Air-spaced achromatic lenses, full multi-coatings, and BAK-4 prisms deliver sharp, high-contrast images, and the 90-deg eyepiece angle makes observing more comfortable. Included 20-power eyepieces deliver a 63-deg apparent field of view. 25x or 16x interchangeable eyepieces (Sold Separately) let you vary the magnification for deep-sky, wide-field solar system, and terrestrial viewing - with 3D-like depth of field! Sturdy all-metal body design has retractable lens shades, removable carrying handle, and metal objective lens caps. The 1/4" -20 mounting base attaches to Orion photo tripods. Weighs 8 lbs., 15 oz. One-year limited warranty.
Please note this product was not designed or intended by the manufacturer for use by a child 12 years of age or younger.
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Product Specifications:
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Use
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Astronomy |
Telescopes can have multiple uses depending on their design. Refractors and Cassegrains can provide a "correct-image" view, so they can be used for daytime land viewing as well as astronomy. Reflectors render the image upside down so they are not recommended for daytime viewing. This is not an issue for astronomy, however, because there's no "right-side up" in space.
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Magnification
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20x |
A measure of the enlargement of an object seen through an optical instrument. More specifically, it is a measure of the angle subtended by an image viewed with optical aid divided by the angle subtended by the same object without optical aid. Magnification is determined by dividing the focal length of the telescope (or binocular) by that of the eyepiece. Hence a telescope with a 1200mm focal length and an eyepiece of 40mm yields a magnification of 30x. The human eye is considered 1x magnification.
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Optical diameter
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70mm |
The optical diameter (also known as aperture), is the size of the telescope's main light collecting lens or mirror, measured in millimeters or inches. As the diameter increases, more light is collected and the resolution increases.
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Field of view - angular
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3.0-deg |
The field of view expressed as part of a 360-degree circle. Holding your pinky finger out at arms length is approximately 1-deg wide. To convert this to the linear measurement of "feet at a thousand yards", multiply by 52.5. For example, at 1000 yards distance, a 7-deg binocular will see a width of 367.5 feet (7 x 52.5)
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Field of view - linear
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157.5 ft./1000 yd |
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Apparent field of view
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60.0-deg |
The edge-to-edge angular diameter of the light emerging from the eyepiece as seen by the eye. It is an inherent specification for a given eyepiece type or design. The apparent field of view of an eyepiece is directly related to the true field of view seen through the telescope; for a given focal length eyepiece, the greater the eyepiece's apparent field of view, the greater area of sky will be seen.
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Eye relief
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15.5mm |
The distance, measured in millimeters, between the observer's eye and the eyepiece lens in which the entire field of view remains visible. Eye relief varies with the optical design but generally increases with decreasing magnification. Long eye relief is advantageous for observers who wear glasses, as they don't have to put their eye directly on the eyepiece to see the entire field of view, nor do they have to remove their eyewear.
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Exit pupil
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3.5mm |
The diameter of the circle of light exiting the telescope eyepiece. It appears as a distinct disk when the telescope is pointed at a bright source like the Moon. Also known as the Ramsden disk, the exit pupil varies with both aperture and magnification.
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Near focus
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50 ft. |
The minimal distance at which a binocular and/or spotting scopes can attain focus. Near focus is an important quality for bird watchers and wildlife devotees who want to get as close as possible to their quarry.
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Coatings
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Fully multi-coated |
Lenses are coated with an anti-reflective material to ensure that as little light as possible is reflected away, thus more gets to your eye. Good lenses are at least "fully coated," with a single layer of magnesium fluoride applied to each air-to-glass lens surface. Multiple layers of coatings are even more effective; the term "multi-coated" means one or more lens surfaces have multiple coatings. "Fully multi-coated" is superior because all lens surfaces are multiple-layer coated.
Mirror star diagonals are coated with a reflective material similar to telescope mirrors in order to reflect the light into the eyepiece. Standard aluminum coatings reflect between 88%-92%, and enhanced aluminum reflects 97%.
Dielectric coatings use a different process to deposit a coating that reflects 99% of the light. In addition to the higher reflectivity, Dielectric coatings are much more durable than aluminum coatings, so they last longer and can be cleaned with less risk of damage.
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Prism type
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BAK-4 Porro |
Porro Prisms:
A binocular prism system that contains two right-angle prisms in each barrel offset from one another, requiring that the objective lenses be spaced farther apart than the eyepieces. Optically, Porro prisms often perform better than their Roof prism counterparts.
Roof Prisms are a compact binocular prism system that allows the objective lenses to line up directly with the eyepieces and hence yields a more portable binocular. Roof prism binoculars lose slightly more light to reflections than Porro prism binoculars. High-quality roof prism binoculars compensate for this with special optical coatings.
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Interpupilary distance range
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57mm - 74mm |
The distance between the two pupils of an observer's eyes. Binoculars can be adjusted to accommodate variations in a person's interpupilary distance.
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Focus style
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Individual eyepiece focus |
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Waterproof
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No |
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Tripod adaptable
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Yes |
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Diopter adjustment
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Yes |
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Weight
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8.9 lbs. |
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Height
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12.2 in. |
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Additional included accessories
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Foam-fitted hard carying case |
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Other features
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Removable handle |
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Warranty
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One year |
Included Items:
Binocular Telescope eyepiece set (20x)
Lens caps
Hard carry case
Binocular Case strap
Lens cleaning cloth
Locking case keys
Binocular handle
White gloves
Orion BT70 Premium Binocular Telescope
Reviewer: John A. Combes
I found the BT70 very good as to optical
quality, steadiness, and ease of viewing.
There is one thing the scope should have
is a finder such as the EZFinder that
could be mounted on the same fitting as
the handle. After set up, remove the
handle and screw in the finder and then
align the finder and you are ready for a
good observing session.
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