Takahashi TPL-33 Plossl Eyepiece

Product Overview

The TPL-33 is a 33 mm Plossl eyepiece from Takahashi's TPL series, the line that replaced the company's earlier Abbe and LE eyepieces. It gives a 48° apparent field with 23 mm of eye relief, from four elements in two groups — the classic Plossl configuration, built in high-refraction, low-dispersion glass that Takahashi states cuts center-field chromatic aberration to roughly half the level of the Abbe series.

At 33 mm it is one of the lower-power members of the TPL range — a wide-true-field eyepiece for scanning star fields rather than resolving fine detail.

Who It's For

This is a good match if you want a low-power eyepiece for sweeping star fields, large open clusters and the Milky Way, with generous 23 mm eye relief for relaxed viewing. The 48° field is the traditional Plossl width — narrower than a modern wide-field design, and correspondingly simpler and less expensive to produce well.

It is a visual eyepiece. Imaging trains connect a camera directly and do not use one.

Key Features & Design

• 33 mm focal length: low power and a wide true field on most Takahashi telescopes — see Compatibility for real figures.
• 48° apparent field: the traditional Plossl field width, sharp across the center with mild softening toward the edge.
• 23 mm eye relief: generous eye position, comfortable over glasses for most frames.
• 4 elements in 2 groups: the symmetric Plossl configuration.
• High-refraction, low-dispersion glass: tightens center-field chromatic correction relative to Takahashi's earlier Abbe and LE eyepieces.
• Multi-coated optics: 99% visible-light transmission with a matte barrel finish to control stray light.

Optical Design

The Plossl design pairs two achromatic doublets symmetrically around the field stop — four elements in two groups, a formula that has stayed in production for decades because it produces a sharp, high-contrast image at reasonable cost. Takahashi's TPL series builds it in higher-refraction, lower-dispersion glass than the company's earlier Abbe and LE lines, which measurably tightens chromatic correction at the center of the field.

Takahashi describes the TPL series as sharp from the center out to roughly the halfway point of the 48° field, with mild star distortion toward the corners — typical of the Plossl form at this field width. Takahashi states that pairing the series with the 2x Ortho Barlow clearly improves flatfieldness, with the combination approaching full-field correction.

Recommended Uses

• Wide star fields and the Milky Way at low power.
• Large open clusters that overflow the field of a higher-power eyepiece.
• Relaxed viewing sessions where 23 mm of eye relief matters, including for glasses wearers.
• A low-power finder-style eyepiece for locating targets before switching to higher power.
• Paired with the 2x Ortho Barlow for a flatter field at roughly double the power.

Compatibility and Accessory Notes

• Magnification: divide your telescope's focal length by 33. An FS-60CB at 355 mm gives about 11x; an FC-100DZ at 800 mm gives about 24x; a Mewlon 210 at 2415 mm gives about 73x.
• Barrel: 31.7 mm — a standard 1.25-inch fit for Takahashi and most third-party diagonals and focusers.
• Diagonal: in a refractor you will normally use it behind a star diagonal. The Takahashi 1.25-inch prism diagonal is a direct pairing.
• 2x Ortho Barlow: Takahashi publishes that flatfieldness across the TPL series clearly improves when used through the 2x Ortho Barlow, at roughly double this eyepiece's magnification.
• Back focus: for adapter and spacing questions across your imaging or visual train, see the Takahashi Back Focus Guide.

Good to Know Before You Order

• 48° is a traditional field, not an ultra-wide one. An 82° or 100° eyepiece gives a more immersive view; the TPL trades that width for a simpler design that still delivers a sharp center field.
• Magnification depends on your telescope. The same 33 mm gives about 11x on a short 60 mm refractor and 73x on a Mewlon 210 — send us your telescope model and we will confirm where it lands in your eyepiece set.
• It is a visual eyepiece. Camera trains connect directly to the telescope or its corrector.
• 160 g is light — it will not register in most focuser-balance calculations.

Frequently Asked Questions

Is it difficult to set up?

No — it drops into a 1.25-inch diagonal or focuser and you focus. Nothing to assemble or adjust.

What magnification will I get?

Your telescope's focal length divided by 33. Send us your telescope model and we will work out where it fits alongside the eyepieces you already own.

How does it compare to Takahashi's older Abbe and LE eyepieces?

The TPL series uses higher-refraction, lower-dispersion glass, cutting center-field chromatic aberration to roughly half the Abbe level and about two-thirds of the LE level.

Is it good for deep-sky observing?

Yes — at 33 mm it gives one of the widest true fields in the TPL range, suited to large clusters and star fields rather than high-power planetary detail.

Can I use it with glasses?

23 mm of eye relief is comfortable for most glasses wearers.

Will it work with a Barlow?

Yes — the 2x Ortho Barlow doubles the magnification and, per Takahashi, improves the TPL series' flatfieldness at the same time.

Is it parfocal with other Takahashi eyepieces?

Switching between eyepiece families will call for a refocus.

Bottom Line

In short: a 33 mm Plossl eyepiece with a 48° field and 23 mm of eye relief, built from four elements in two groups with glass chosen to keep the center field free of chromatic aberration. It suits low-power, wide-field viewing, and flattens out further when paired with Takahashi's 2x Ortho Barlow.