Takahashi TOE 3.3mm Eyepiece - 1.25"

Product Overview

The TOE 3.3 mm is the shortest focal length in Takahashi's TOE range — a 1.25″ eyepiece built for high-magnification visual observing. Its six-element optical design minimises spherical and chromatic aberration, and the 52° apparent field matches that of Takahashi's LE series, with 10 mm of eye relief.

At 3.3 mm, this is a planetary and double-star eyepiece. On a 1000 mm telescope it delivers roughly 300x; on a 2500 mm Mewlon, above 750x — magnifications that reward good optics and steady seeing.

Who It's For

This is a good match if you observe planets, the Moon, or close double stars and want the shortest focal length in the TOE line on a premium telescope.

Key Features & Design

• 3.3 mm focal length: the highest magnification in the TOE range.
• 52° apparent field: matched to Takahashi's LE series.
• 10 mm eye relief: consistent across the TOE line.
• Six-element design: minimises spherical and chromatic aberration.
• 1.25″ barrel: fits any standard 1.25″ focuser or diagonal.

Optical / Mechanical Design

A short-focal-length eyepiece is the hardest kind to build well. Aberrations that stay invisible at 25 mm become obvious at 3.3 mm, and simple designs tend to give up eye relief as focal length falls — which is why cheap high-power eyepieces are so uncomfortable to use. The TOE answers both with six elements: enough degrees of freedom to control spherical and chromatic error while holding eye relief at 10 mm even at this focal length. Takahashi's stated aim for the range is performance close to the diffraction limit across the whole field when paired with a premium telescope.

Recommended Uses

High-magnification visual observing: planetary detail, lunar features at the terminator, and splitting close double stars.

Compatibility and Accessory Notes

The 1.25″ barrel fits any standard 1.25″ focuser, diagonal, or 2″-to-1.25″ adapter. Takahashi publishes this eyepiece as not parfocal, so refocusing is needed when swapping to another eyepiece. The TOE line also includes 4 mm, 5.5 mm, 7.5 mm and 10 mm focal lengths, which we stock — if you are building a set and want to space the magnifications sensibly on your telescope, tell us the focal length and we will suggest a combination.

Good to Know Before You Order

A visual eyepiece: the TOE is designed for the eye rather than a sensor, and has no application in a prime-focus imaging train.

Not parfocal: swapping between TOE focal lengths needs a touch of refocusing.

Magnification depends on your telescope: divide your focal length by 3.3. On longer instruments this eyepiece reaches magnifications that only steady seeing will support — which is exactly what it is built for, and worth pairing with a longer TOE for nights when the air is not cooperating.

Frequently Asked Questions

Is it difficult to set up?

No — it drops into a 1.25″ focuser or diagonal like any eyepiece. It does need refocusing when you swap eyepieces, since the TOEs are not parfocal.

What magnification will I get?

Your telescope's focal length divided by 3.3. A 1000 mm telescope gives about 300x.

What is it best used for?

Planets, the Moon, and close double stars — targets that reward high magnification.

Is the eye relief comfortable?

10 mm, which is generous for a 3.3 mm eyepiece; short focal lengths in simpler designs typically offer far less.

Can I use it for astrophotography?

It is a visual eyepiece and has no application in a prime-focus imaging train.

Bottom Line

Takahashi's shortest TOE — a six-element 3.3 mm eyepiece with a 52° field and 10 mm of eye relief, made for the nights when the seeing lets you push the magnification.