Takahashi TPL-6 Plossl Eyepiece

Product Overview

The TPL-6 is a 6mm eyepiece from Takahashi's TPL Plossl series, the successor to the older Abbe and LE lines. It uses a 4-elements-in-2-groups Plossl design built with high-refraction, low-dispersion glass, giving a 48° apparent field of view and 4.5mm of eye relief. It weighs 55g and uses the standard 31.7mm (1.25”) barrel.

Who It's For

This is a good match if you want the shortest, highest-power focal length in the TPL series — for planetary detail, lunar close-ups, and tight double stars on nights when the seeing supports it.

Key Features & Design

• 4-element, 2-group Plossl design: the current evolution of Takahashi's Plossl line, replacing the older Abbe and LE series.
• High-refraction, low-dispersion glass: Takahashi states this cuts chromatic aberration at the center of the field to roughly half the level of the Abbe series and two-thirds that of the LE series.
• Multilayer coatings at 99% transmission: keeps the image bright despite the four-element count.
• Matte-finished interior: reduces stray light and internal reflections for better contrast.
• 48° apparent field of view and 4.5mm eye relief at this focal length.

Optical / Mechanical Design

Takahashi describes the TPL series as sharp from the center out to roughly halfway across the field, with only mild star distortion at the corners on its own — and notes that pairing a TPL eyepiece with the 2x Ortho Barlow (sold separately) measurably flattens the field, producing close to full-field correction. At 6mm, the TPL-6 sits at the short end of the series, where the Plossl design's center-field sharpness is what matters most for planetary and lunar detail.

Recommended Uses

On a Takahashi TSA-120 (900mm, f/7.5) the TPL-6 gives about 150x, a strong planetary and lunar magnification on a night of good seeing. On a Takahashi FS-60CB (355mm, f/5.9) the same eyepiece yields roughly 59x, useful high power for a small travel refractor. Divide any Takahashi tube's focal length by 6mm for the magnification on your own setup.

Compatibility and Accessory Notes

The 31.7mm (1.25”) barrel fits any Takahashi focuser, star diagonal, or 2″-to-1.25” adapter in the current lineup. Takahashi's own literature notes that combining the TPL-6 with the 2x Ortho Barlow improves flat-field performance across the whole view — worth considering if you already use a Barlow in your kit or are deciding whether to add one.

Good to Know Before You Order

Not parfocal: a refocus is needed when swapping the TPL-6 in from another eyepiece in your case.

4.5mm eye relief is tight: comfortable bare-eyed; eyeglass wearers may find a longer-eye-relief eyepiece easier at this magnification, or may prefer observing without glasses and adjusting focus to compensate.

Frequently Asked Questions

Is it difficult to set up?

No — it threads directly into a standard 1.25” focuser or diagonal. The short eye relief takes a little care in eye placement, but there's no assembly involved.

What is it best used for?

High-power visual observing — planetary detail, lunar close-ups, and tighter double stars, on nights with steady seeing.

How does it compare to the Starbase OR-6mm?

Both are 6mm, 4-element eyepieces with a 1.25” barrel. The TPL series uses Takahashi's higher-refraction, low-dispersion glass and multilayer coatings rated at 99% transmission, positioning it a step up from the Starbase budget line at a correspondingly higher price.

What telescopes does it fit?

Any Takahashi refractor or reflector with a standard 1.25” focuser or diagonal.

Bottom Line

A 6mm Plossl eyepiece with a 48° field, 4.5mm eye relief, and a 55g weight — the highest-power option in Takahashi's TPL series, built around high-refraction, low-dispersion glass for planetary and lunar detail. If you're building a full eyepiece set and want help matching focal lengths to your telescope, send us your setup and we'll work it out with you.