7mm 1.25" 90° Ultra Wide/Flat Field

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The high power Takahashi 7mm Ultra Wide/Flat Field 1.25” eyepiece is a new and original eight lens/five group optical design with an ultra-wide 90° apparent field of view. The field is exceptionally flat, with pin point stars across the entire 90° field. This aplanatic eyepiece is designed to be free from coma and spherical aberrations.

This 7mm Takahashi eyepiece was designed for high power use with flat field telescopes. Such scopes include the Takahashi FSQ refractors, Takahashi Corrected Mewlons and Mewlons with separate MCR correctors, Takahashi FS-60Q and TOA refractors with field flatteners, and all other brands of flat field telescopes (whether the flat field is produced by a scope alone or a scope/field flattener combination).

This new design Takahashi eyepiece has a usable 12mm eye relief and a twist-up eyecup to shield your eye from stray light. Viewing with glasses is only necessary if there is astigmatism present in the observer’s vision. Otherwise, the observer can view without glasses and still enjoy an ultra wide field of view.

All internal surfaces are painted with optical flat black paint to prevent ghost images and to insure the greatest possible contrast. A rubber grip ring around the barrel provides a sure grip in cold or damp weather.

The Takahashi 7mm Ultra Wide/Flat Field eyepiece is somewhat substantial in size and weight, although it compares favorably with similar eyepieces from other manufacturers. It has a 60mm maximum barrel diameter (2.36”) and a 120mm length (4.7”), with a weight of 15.1 ounces.

Field of view:
The field of view (FOV) is the amount of observable world one can see at any given moment.
Eye Relief:
Eye relief is the distance from the last surface of the eye lens of an eyepiece to the plane behind the eyepiece where all the light rays of the exit pupil come to a focus and the circular image is formed, sometimes called the “Ramsden Disk.” This is where your eye should be positioned to see the full field of view of the eyepiece. If you must wear glasses because of astigmatism, you’ll usually need at least 15mm of eye relief or longer if you want to see the full field of view with your glasses on.

A note on our eye relief figures: Quite often, our eye relief figures will differ from those of the manufacturer. This is because we measure the “usable” eye relief, while the manufacturers specify their usually-longer (but technically correct) “designed” eye relief.

The eye lens of the eyepiece is normally recessed below the rubber eyeguard or rubber rim of the eyepiece to keep the lens from being scratched during use. An eyepiece might have a “designed” eye relief of 15mm (and the eye relief will truly measure 15mm from the eye lens to where the image forms). However, if the eye lens is recessed 3mm below the eye guard, the Ramsden Disk forms only 12mm above the eyepiece body (the 15mm “designed” eye relief, less the 3mm of eye relief made unusable by having the eye lens recessed into the body of the eyepiece). This “usable” eye relief of 12mm (measured from the rolled-down eyeguard – the closest point you can get your eye to the eye lens – to where the image forms) is the eye relief figure we would measure and list in this website.

Why is it important to list the “usable” eye relief? For those people who don’t wear eyeglasses while observing, a few mm difference between the eye relief they expect from the manufacturer’s literature and the shorter eye relief they actually get in real life doesn’t mean a lot. They can simply move a little closer to the eyepiece to see the full field, and never realize that the eye relief is a little shorter than they expected. However, some people must wear eyeglasses while observing, because of severe astigmatism. These observers can’t move closer to the eyepiece if the eye relief is shorter than expected because their glasses get in the way. For these people, the real life “usable” eye relief is more important than the technically correct but sometimes not fully usable “designed” eye relief. We measure and list the actual usable eye relief so that people in the real world can pick the eyepieces that will work best for them.

Focal Length:
This is the length of the effective optical path of a telescopeor eyepiece (the distance from the main mirror or lens where the lightis gathered to the point where the prime focus image is formed). Focallength is typically expressed in millimeters.

The longer the focallength, the higher the magnification and the narrower the field of viewwith any given eyepiece. The shorter the focal length, the lower themagnification and the wider the field of view with the same eyepiece.

Number of optical elements:
8 lenses/5 groups
Barrel Size:
The industry standard diameter, as of 2011, is 1.25" and is the most common.  Other sizes available are .965" and 2".
The weight of this product.
15.1 oz.
5 years
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Telescope Eyepiece Formula
To calculate the magnification and approximate actual field of view of this eyepiece on your telescope, enter the focal length of your telescope below and press the "Calculate" button.

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Takahashi - 7mm 1.25" 90° Ultra Wide/Flat Field

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Takahashi - 7mm 1.25" 90° Ultra Wide/Flat FieldSize comparison of a typical Takahashi 1.25" eyepiece with a typical Takahashi Ultra Wide/Flat Field.
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Our Product #: TAKUW07
Manufacturer Product #: TEA0007
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The high power Takahashi 7mm Ultra Wide/Flat Field 1.25” eyepiece has an ultra-wide 90° apparent field of view, free of coma and spherical aberrations, with pin point stars across its remarkably flat field . . .

. . . our 38th year