Tele Vue Delos 10mm — image 1
Tele Vue

Tele Vue Delos 10mm

The most comfortable way to see a planet sharply. A tack-sharp 72-degree field with a full 20 mm of eye relief, the medium-high-power eyepiece you can look into for an hour without a single squint.

91/ 100
Polaris Score
Optical quality · Immersion · Comfort · Value
See the breakdown ↓
What it's for
Low power · wide fieldHigh power · narrow field

A medium-to-high-power eyepiece for detail work: planets, globulars, galaxies and planetary nebulae at a comfortable scale. Wide enough to be immersive, but this is a sharpshooter, not a rich-field sweeper.

Apparent Field
72°
Barrel Size
1.25"
Eye Relief
20mm
Focal Length
10mm
From$438

Lowest in 90 daysLowest ever tracked

Price tracked by PolarisObserved 120 timesTracking since Jun 2026

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The spacewalk

You don’t look at a field.
You look into the sky.

Every number on the spec sheet matters less than one feeling: how much sky wraps around your eye. Widen the apparent field and watch the black edge of the eyepiece slip away.

72° apparent field

At 72°, the black rim sits out at the corner of your attention rather than in front of you.
Try this eyepiece on your own scope in the Simulator →
01What it's good at

What it's best at — and the trade-offs.

A full 20 mm of eye relief at 10 mm focal length, which almost no competitor matches, making long high-power sessions effortless.
Best at
✓A full 20 mm of eye relief at 10 mm focal length, which almost no competitor matches, making long high-power sessions effortless.
✓Pinpoint stars and high contrast right to the edge of the 72-degree field, even at f/5.
✓One of the sharpest, most neutral planetary and lunar views available without stepping up to exotic glass.
Trade-offs
!Expensive for a single focal length, and you'll want two or three to cover the range.
!Heavy; a full kilo of eyepieces will rebalance a light Dob or refractor.
!The 72-degree field is generous but not the ultra-wide immersion of an 82 or 100-degree design.
02In your telescope

One eyepiece. A different job in every scope.

48× in a small refractor, 203× in a long SCT

An eyepiece has no magnification of its own — the telescope decides. The same eyepiece becomes 48× and 1.5° of sky in a little refractor, or 203× and a tight frame in a long SCT. Here’s what it does across common scopes.

Small apo refractor
480 mm · f/5.5
Magnification
48×
True field
1.5°
Exit pupil
1.8 mm
A wide, comfortable 48x and 1.5 degrees in the little refractor; more magnification than you'd think, with the whole field usably sharp.
8-inch Dobsonian
1200 mm · f/6
Magnification
120×
True field
36′
Exit pupil
1.7 mm
120x and a bright 1.7 mm exit pupil in the 8-inch Dob, the sweet spot for globulars, galaxies and the brighter planetary nebulae.
12-inch Dobsonian
1500 mm · f/5
Magnification
150×
True field
29′
Exit pupil
2.0 mm
150x in the big Dob with pinpoint stars to the edge; steady nights reward this scale on Jupiter and Saturn.
8-inch SCT
2032 mm · f/10
Magnification
203×
True field
21′
Exit pupil
1.0 mm
203x out of the long SCT with a 1 mm exit pupil, high-power lunar and planetary detail rendered with easy, relaxed viewing.
Exit pupil is how wide the beam of light leaving the eyepiece is. Around 5–6 mm is bright and immersive under dark skies; push much past 6 mm and you waste light, and under light pollution a smaller exit pupil shows more contrast.
03In plain English

The numbers, in plain English.

10mm FL · 72° AFOV · 1.25"
20 mm eye reliefThe signature spec
Effortless
You sit back from the lens and observe with glasses on, at a focal length where most eyepieces force your eye against the glass.
72° apparent fieldWide, not ultra-wide
Immersive
Enough field that a planet has room to drift and deep-sky objects sit in space, without the size and cost of a 100-degree eyepiece.
Edge sharpnessHolds at f/5
Pinpoint
Stars stay tight and neutral to the field stop even in fast scopes, the hard part of eyepiece design, solved.
~350 gRebalances light scopes
Substantial
You'll feel it in a small refractor or grab-and-go Dob; a fair trade for the view and comfort.
04What comes alive

The targets this eyepiece was born for.

Jupiter, Saturn, The Moon, Ring Nebula, M13 Hercules Cluster, Double stars
JupiterComes alive
Jupiter
Belts, festoons and the Great Red Spot in a sharp, high-contrast, and above all comfortable high-power view.
SaturnComes alive
Saturn
The Cassini Division and banded disc hold steady, framed with room to watch it drift.
The MoonComes alive
The Moon
Crater walls and rilles at the terminator, with the eye relief to scan for long stretches without fatigue.
Ring NebulaExcellent
Ring Nebula
Small but bright; this focal length lifts it from a smoke ring to a structured, three-dimensional shell.
M13 Hercules ClusterExcellent
M13 Hercules Cluster
Resolves cleanly into thousands of stars in an 8-inch and up, set in a sharp, dark field.
Excellent
Double stars
Tight pairs split cleanly thanks to the high contrast and edge-to-edge sharpness.
05Role in a collection

Where it sits in your eyepiece case.

Where it sits across 3 focal lengths

A good eyepiece collection isn’t a pile of glass — it’s two or three focal lengths that hand off from wide to tight. This is the anchor at the bottom of the ladder: the one you find and frame with. You buy it once, and it stays your low-power eyepiece for life.

32 mm
Low power · wide field
Find, frame and sweep. Your widest true field and the lowest useful magnification, the eyepiece you reach for first.
Veil Nebula · Pleiades · Milky Way star clouds
10 mmThis one
Medium power · the workhorse
Where most deep-sky objects look their best, galaxies, globulars and planetary nebulae at a comfortable scale.
M13 · Ring Nebula · most galaxies
7 mm
High power · detail
Planets, the Moon at the terminator, tight double stars and the smallest planetary nebulae. Steady-air nights only.
Jupiter · Saturn · lunar craters
06Build around it

What it pairs with.

The telescope · Pair it · Filter it
The telescope
What it goes into
Any scope, fast or slow
Its edge correction holds even at f/5, so it flatters Newtonians and refractors alike
8-inch and up for deep sky
Aperture turns the high power into resolved globulars and structured nebulae
Long SCT for planets
High native magnification plus this eyepiece's comfort is a superb planetary pairing
Pair it
What extends its range
A wide-field 2" eyepiece
The find-and-frame partner; you locate wide, then drop in the Delos to zoom
Another Delos or two
Parfocal within the line, so you barely touch the focuser swapping between them
Filter it
What transforms the view
Planetary / colour filters
The high contrast is a good base for teasing out belt and polar detail
OIII on planetary nebulae
At this focal length the Ring and similar shells take a filter well
07The Polaris Score

How it scores, and why.

91/100
91/ 100
Tele Vue Delos 10mm

Judged on delivering a sharp, high-contrast, genuinely comfortable medium-to-high-power view, it is close to flawless in any scope, fast or slow. The only real marks against it are price and weight, never the view itself.

Optical quality
95
Immersion
85
Comfort
96
Value
80

Polaris weighs how well the eyepiece does the job it was designed for — optics, immersion, comfort and value — never list price or brand.

08Who it's for

An honest fit check.

You want planets, the Moon and small deep-sky objects rendered as sharply as your scope can…
Buy it if you
✓You want planets, the Moon and small deep-sky objects rendered as sharply as your scope can manage, with zero eye strain.
✓You wear glasses, or simply hate pressing your eye into a tiny lens; the 20 mm of eye relief is transformative at this focal length.
✓You own a fast scope and want an eyepiece that stays pin-sharp to the edge without a coma corrector doing all the work.
✓You are building a buy-once eyepiece case and want the medium-high-power slot filled for good.
Look elsewhere if you
!You want the widest possible true field for sweeping; a long-focal-length wide-angle does that job, not this.
!You are on a tight budget, where a Celestron X-Cel or Explore Scientific gives most of the view for a quarter of the price.
!You need it to stay light; at over 350 grams it can rebalance a small scope.
!You already observe happily with short eye relief and won't pay a premium purely for comfort.
09The numbers

Full specifications.

4 measured and stated values
Optical
Focal Length10mm
Apparent Field72°
Comfort & handling
Eye Relief20mm
Fit & build
Barrel Size1.25"
Editor’s Take

The Delos took the one thing Tele Vue's legendary eyepieces asked you to give up, comfortable eye relief at high power, and simply gave it back. Once you've spent a night behind one, cramped short-focal-length eyepieces start to feel like a compromise you no longer have to make.

— The Skynocular verdict
10Alternatives

For a different goal, start here.

3 alternatives, each mapped to the goal it wins at
The rival

Pentax XW 10mm

The other 20 mm-eye-relief high-power reference; weather-sealed, 70 degrees, and the classic head-to-head with the Delos.

One step wider

Tele Vue Delos 14mm

The same eyepiece a notch lower in power, for a touch more field and a larger exit pupil.

→
Budget alternative

Celestron X-Cel LX 9mm

Most of the comfort and a good sharp view for a quarter of the price, if the Delos is a stretch.

→