Takahashi TOE-2.5mm eyepiece (31.7mm) telescope Toe Series new For Sale
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Takahashi TOE-2.5mm eyepiece (31.7mm) telescope Toe Series new:
$385.00
Description
■Easy to use high magnification eyepiece
●The ultimate visual observation is observation using an excellent eyepiece and an excellent telescope that is close to the diffraction limit. With this combination, the resolution of the telescope optics can be delivered to the entire field of view. The TOE eyepiece was developed based on this concept. If you have an astronomical telescope equipped with a high-performance objective lens, you can use the TOE eyepiece not only with our products but also with other companies\' products, to fully demonstrate the performance of the objective lens and obtain a high-resolution image that you can fully appreciate over the entire field of view. will deliver.
●TOA, FOA, FSQ, TSA, Mewlon-CRS, etc., which have corrected aberrations to the utmost limit, are not only useful as photographic mirrors, but also can be used as systems that even visual users can fully understand by using the TOE eyepiece. Masu.
●The TOE eyepiece was designed with priority given to easy-to-use magnification and easy-to-see visibility when observing the moon and planets at high magnification. When TOE-2.5mm, TOE-3.3mm, and TOE-4.0mm are attached to TOA-130, the magnification will be 400x, 300x, and 250x, respectively. This is a lineup with a focal length that is more than the 320x excess magnification for double stars, and is perfect for changing the magnification depending on the viewing conditions. If you are trying to get high magnification with f/5 FSQ, you will get better results by attaching a special extender to f/8 and then increasing the magnification.
●The apparent field of view is 52°, which is wider than the Hi-LE\'s 40°, which is the same as other LE series, and the eye relief is also 10mm, the same as the LE-5mm and LE7.5mm, making it the same as other Takahashi eyepieces. Since it is parfocal, it is easy to use as an ultra-high magnification eyepiece. The wide apparent field of view makes it easy to install and use even if you use it exclusively for planets.
■Aberration evaluation using Strehl ratio and spot diagram
●When the eyepiece is combined with an objective lens, it becomes an afocal optical system, which does not form an image, making it difficult to evaluate aberrations. At Takahashi, the eyepiece is optically designed as an afocal system in combination with TOA-130. In addition, we use the Strehl ratio, which is the ratio to the diffraction-limited optical system, for wave optical evaluation, and the spot diagram for geometric optical evaluation. If you look at the figure below, you can see that the Strehl ratio is over 98% over the entire visible wavelength range from 486nm to 656nm and the entire visual field.
●I\'m not familiar with eyepiece spot diagrams because they are rarely published, but the round frame is the angle of 10 microradians. The resolution of an aberration-free lens with an aperture of 130 mm can be calculated from the dose limit formula as 0.9 arc seconds = 4.5 microradians, which means that all TOE series lenses are well below the diffraction limit in the entire field of view. It also shows that lateral chromatic aberration (color shift at the periphery), which is difficult to completely eliminate with an eyepiece, is extremely low.
■Takahashi\'s unique lens configuration
●The optical design of the TOE series, which consists of 6 elements in 4 groups, is Takahashi\'s unique lens configuration that is optimized by integrating the Smythe lens in the front group and the master lens in the rear group. It is designed to minimize aberrations such as aberration, distortion, and lateral chromatic aberration.
●In addition, by selecting a lens curvature that reduces ghosting and flare, and by designing the hardware, you can observe the moon and planets with images with good contrast. A broadband multi-coat is applied to each boundary surface of the lens, and a flat multi-coat is applied to necessary surfaces to correct color balance and improve contrast.
●Furthermore, the edges of the lenses are black-painted, and the metal parts are also matte-treated to prevent stray light.
Specification table
▼Takahashi LE Eyepiece Series/Specifications
Product name Product code Apparent field of view Eye relief Lens configuration Weight Mounting size
TOE-2.5mm KA00613 52ﾟ 10mm 4 groups 6 elements 145g 31.7mm
TOE-3.3mm KA00614 52ﾟ 10mm 4 groups 6 elements 140g 31.7mm
TOE-4.0mm KA00615 52ﾟ 10mm 4 groups 6 elements 140g 31.7mm
Shipping
Normal shipping (FedEX,Japan Post) will arrive in 7-14 days. Please note that irregular delays may occur due to weather or customs issues.
【Expedited】FedEx orEMS : with tracking number
Foreign Buyers - Please Note:
Import duties, taxes and fees are not included in the price or shipping. These charges are the responsibility of the buyer.
Please check with your country\'s customs to see how much these additional costs will be before you bid or purchase.
Thank you for your understanding.
