Baader Classic Ortho 6mm — image 1
Baader Planetarium

Baader Classic Ortho 6mm

A 6mm Baader Classic Ortho: a dedicated high-power eyepiece for planets, the Moon and tight double stars, from a four-element orthoscopic built for maximum contrast on planets and the Moon.

73/ 100
Polaris Score
Optical quality · Immersion · Comfort · Value
See the breakdown ↓
What it's for
Low power · wide fieldHigh power · narrow field

High power. At 6mm this is a dedicated high-power eyepiece for planets, the Moon and tight double stars; it is not meant for framing large deep-sky objects.

Apparent Field
50°
Barrel Size
1.25"
Eye Relief
5mm
Focal Length
6mm
From$108

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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.

50° apparent field

At 50°, you are aware of the field edge, like looking down a short, comfortable tube.
Try this eyepiece on your own scope in the Simulator →
01What it's good at

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

Superb on-axis contrast and light throughput; four elements scatter almost nothing.
Best at
✓Superb on-axis contrast and light throughput; four elements scatter almost nothing.
✓Superb on-axis contrast and light throughput; four elements scatter almost nothing.
✓At 6mm it lands squarely in high power territory, exactly where planetary and lunar detail lives.
Trade-offs
!A narrow 50-degree field; the object drifts through quickly on an undriven mount.
!Tight eye relief at short focal lengths, which is uncomfortable for eyeglass wearers.
!Not the eyepiece for large deep-sky objects that want a wide field.
02In your telescope

One eyepiece. A different job in every scope.

80× in a small refractor, 339× in a long SCT

An eyepiece has no magnification of its own — the telescope decides. The same eyepiece becomes 80× and 38′ of sky in a little refractor, or 339× 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
80×
True field
38′
Exit pupil
1.1 mm
80× across a 38′ field at a 1.1mm exit pupil, crisp medium power for galaxies, clusters and planetary nebulae.
8-inch Dobsonian
1200 mm · f/6
Magnification
200×
True field
15′
Exit pupil
1.0 mm
200× across a 15′ field at a 1mm exit pupil, high power for planets, the Moon and tight doubles.
12-inch Dobsonian
1500 mm · f/5
Magnification
250×
True field
12′
Exit pupil
1.2 mm
250× across a 12′ field at a 1.2mm exit pupil, crisp medium power for galaxies, clusters and planetary nebulae.
8-inch SCT
2032 mm · f/10
Magnification
339×
True field
9′
Exit pupil
0.6 mm
339× across a 9′ field at a 0.6mm exit pupil, very high power, worth it only on the steadiest nights.
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.

6mm FL · 50° AFOV · 1.25"
Focal lengthVery high power
6mm
About 200x in an 8 inch f/5.9 Dobsonian and 339x in an 8 inch SCT. That is the top of the useful range for most nights, and it is exactly where an orthoscopic design is meant to be used: planets, the lunar terminator and tight double stars.
Apparent fieldClassic
50°
Fifty degrees is a modest field by modern standards, and deliberately so. Fewer elements mean less scattered light and higher contrast, which on a planet matters more than field width. In an undriven Dobsonian it does mean nudging the tube frequently at this power.
Eye reliefVery tight
5mm
Five millimetres puts your eye almost against the lens. Glasses are impossible and even eyelashes become a nuisance, which is the long-standing price of short-focal-length orthoscopics. Some observers prefer a longer eyepiece with a Barlow for this reason.
BarrelStandard
1.25"
Fits any focuser or diagonal, and the light weight means it will not shift a Dobsonian's balance when you swap it in at high power.
OpticsPlanetary specialist
Fully multi-coated
A four-element Abbe orthoscopic with full multi-coating: very few air-to-glass surfaces, so very little light is scattered. That is why this simple design still outperforms complex wide-field eyepieces on planetary contrast.
04What comes alive

The targets this eyepiece was born for.

Jupiter’s cloud belts, Saturn’s rings, Lunar craters at the terminator, Izar and tight…
Jupiter’s cloud beltsComes alive
Jupiter’s cloud belts
The two main belts and festoons resolve on steady nights.
Saturn’s ringsComes alive
Saturn’s rings
The Cassini Division opens up at this magnification.
Lunar craters at the terminatorExcellent
Lunar craters at the terminator
Crater walls and central peaks throw hard shadows.
Excellent
Izar and tight double stars
Splits pairs under an arcsecond apart when the air is calm.
Mars at oppositionExcellent
Mars at opposition
Polar cap and dark albedo markings when Mars is close.
The Ring Nebula (M57)Excellent
The Ring Nebula (M57)
Tightens the smoke ring and darkens the sky around it.
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
13 mm
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
6 mmThis one
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 1.25-inch focuser
Fits essentially every telescope made.
Longer focal length scopes reward it
The higher the scope’s focal length, the more planetary scale you get from this eyepiece.
Pair it
What extends its range
A low-power finder eyepiece (~10mm)
Use the long eyepiece to locate and frame, then drop in this one for detail.
Filter it
What transforms the view
A neutral-density Moon filter
Tames the glare of a bright gibbous Moon at high power so detail returns.
07The Polaris Score

How it scores, and why.

73/100
73/ 100
Baader Classic Ortho 6mm

Judged as a dedicated high-power eyepiece for planets, the Moon and tight double stars, it earns its score on superb on-axis contrast and light throughput; four elements scatter almost nothing. Tighter eye relief at this focal length is the main thing holding it back. It is honest about being a specialist, not an all-rounder.

Optical quality
86
Immersion
56
Comfort
42
Value
84

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.

Observers who want a dedicated high-power eyepiece for planets, the Moon and tight double…
Buy it if you
✓Observers who want a dedicated high-power eyepiece for planets, the Moon and tight double stars.
✓Observers happy to take their glasses off at the eyepiece.
✓Observers who value on-axis contrast over a sprawling field.
Look elsewhere if you
!Anyone who has looked through a wide-field eyepiece and cannot go back to a 52-degree tunnel.
!Eyeglass wearers, who will not comfortably reach the full field at this focal length.
!Anyone hoping to frame large nebulae; that is a job for a low-power eyepiece.
09The numbers

Full specifications.

4 measured and stated values
Optical
Focal Length6mm
Apparent Field50°
Comfort & handling
Eye Relief5mm
Fit & build
Barrel Size1.25"
Editor’s Take

Point it at a planet on a steady night and the case makes itself. This is where the Classic Ortho earns its keep.

— The Skynocular verdict
10Alternatives

For a different goal, start here.

2 alternatives, each mapped to the goal it wins at
Wider, lower power

Baader Classic Ortho 10mm

The same optics with more true field, for framing larger objects and finding your way around.

→
Cross-shop

Celestron X-Cel LX

A natural alternative at a similar price point, if you want to compare field and feel before committing.

→