Celestron Ultima Edge 15mm — image 1
Celestron

Celestron Ultima Edge 15mm

A 15mm Celestron Ultima Edge: the workhorse magnification where most galaxies, globulars and nebulae look their best, from a flat-field 65-degree eyepiece that stays sharp to the edge in fast scopes.

80/ 100
Polaris Score
Optical quality · Immersion · Comfort · Value
See the breakdown ↓
What it's for
Low power · wide fieldHigh power · narrow field

Medium power. At 15mm this is the workhorse magnification where most galaxies, globulars and nebulae look their best.

Apparent Field
65°
Barrel Size
1.25"
Eye Relief
16mm
Focal Length
15mm
From$159.95

Lowest in 90 daysLowest ever tracked

Price tracked by PolarisObserved 103 timesTracking since Jul 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.

65° apparent field

At 65°, 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.

Comfortable 16mm eye relief across the line.
Best at
✓Comfortable 16mm eye relief across the line.
✓A genuinely flat field: sharp corner to corner, even in f/5 Newtonians.
✓At 15mm it lands squarely in medium power territory, exactly where most deep-sky objects look their best.
Trade-offs
!A 65-degree field, wider than a Plössl but short of a true ultra-wide.
!The lineup covers fewer focal lengths than the big modular ranges.
!Eyecup adjustment is basic.
02In your telescope

One eyepiece. A different job in every scope.

32× in a small refractor, 135× in a long SCT

An eyepiece has no magnification of its own — the telescope decides. The same eyepiece becomes 32× and 2.0° of sky in a little refractor, or 135× 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
32×
True field
2.0°
Exit pupil
2.7 mm
32× across a 2.0° field at a 2.7mm exit pupil, right in the deep-sky sweet spot, bright and easy on the eye.
8-inch Dobsonian
1200 mm · f/6
Magnification
80×
True field
49′
Exit pupil
2.5 mm
80× across a 49′ field at a 2.5mm exit pupil, right in the deep-sky sweet spot, bright and easy on the eye.
12-inch Dobsonian
1500 mm · f/5
Magnification
100×
True field
39′
Exit pupil
3.0 mm
100× across a 39′ field at a 3mm exit pupil, right in the deep-sky sweet spot, bright and easy on the eye.
8-inch SCT
2032 mm · f/10
Magnification
135×
True field
29′
Exit pupil
1.5 mm
135× across a 29′ field at a 1.5mm exit pupil, crisp medium power for galaxies, clusters and planetary nebulae.
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.

15mm FL · 65° AFOV · 1.25"
Focal lengthMid power
15mm
About 80x in an 8 inch f/5.9 Dobsonian and 135x in an 8 inch SCT. The general-purpose range where galaxies keep a dark background and cluster stars begin to separate cleanly.
Apparent fieldWide
65°
Sixty-five degrees gives a genuinely open view without pushing the optical design past what it can correct at fast focal ratios. You gain immersion without paying for it at the field edge.
Eye reliefComfortable
16mm
Comfortable for extended viewing and usable with thin spectacles, so you can settle in on a faint object rather than constantly repositioning.
BarrelStandard
1.25"
Fits every standard focuser and diagonal, with no adapters and no weight concerns on a light focuser.
OpticsFlat field
Fully multi-coated
Full multi-coating plus a design aimed at field flatness means stars stay pointlike well out toward the edge, which matters more in everyday use than a few extra degrees of field.
04What comes alive

The targets this eyepiece was born for.

M13 globular cluster, The Whirlpool (M51), The Dumbbell Nebula (M27), M81 and M82, The Ring…
M13 globular clusterComes alive
M13 globular cluster
Resolves to the core with pinpoint stars across the field.
The Whirlpool (M51)Excellent
The Whirlpool (M51)
Two cores and a hint of the bridging spiral arm.
The Dumbbell Nebula (M27)Comes alive
The Dumbbell Nebula (M27)
The apple-core shape framed with dark sky around it.
M81 and M82Excellent
M81 and M82
Both galaxies in one field, one soft, one edge-on and streaky.
The Ring Nebula (M57)Excellent
The Ring Nebula (M57)
A clean smoke ring at a comfortable scale.
The Trapezium in OrionExcellent
The Trapezium in Orion
Four stars split cleanly inside the glowing nebula.
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
15 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 1.25-inch focuser
Fits essentially every telescope made.
Fast, short scopes love this field
A fast Newtonian or refractor turns this focal length into a rich, wide sweep.
Pair it
What extends its range
A high-power eyepiece (~9mm)
Locate and frame with this one, then swap to high power for planets and small objects.
Filter it
What transforms the view
A mild broadband light-pollution filter
Lifts contrast on galaxies and clusters from the suburbs at medium power.
07The Polaris Score

How it scores, and why.

80/100
80/ 100
Celestron Ultima Edge 15mm

Judged as the workhorse magnification where most galaxies, globulars and nebulae look their best, it earns its score on a genuinely flat field: sharp corner to corner, even in f/5 newtonians. The comfortable eye relief lifts it further. It is honest about being a specialist, not an all-rounder.

Optical quality
80
Immersion
75
Comfort
84
Value
82

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 the workhorse magnification where most galaxies, globulars and nebulae…
Buy it if you
✓Observers who want the workhorse magnification where most galaxies, globulars and nebulae look their best.
✓Anyone who observes in eyeglasses; the eye relief here is long enough to see the whole field.
✓Observers who value on-axis contrast over a sprawling field.
Look elsewhere if you
!Anyone chasing the absolute widest field, who should look at a 100-degree eyepiece.
!Grab-and-go observers watching every gram, since this is not the lightest option.
!Planetary specialists who want the last ounce of high-power contrast from an orthoscopic.
09The numbers

Full specifications.

4 measured and stated values
Optical
Focal Length15mm
Apparent Field65°
Comfort & handling
Eye Relief16mm
Fit & build
Barrel Size1.25"
Editor’s Take

Sweep it across a rich star field and the reason to own this focal length is obvious in a second. That is what the Ultima Edge is for.

— The Skynocular verdict
10Alternatives

For a different goal, start here.

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

Celestron Ultima Edge 24mm

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

→
More magnification

Celestron Ultima Edge 10mm

The same line at higher power, for planets and the smallest deep-sky detail.

→
Cross-shop

Tele Vue Panoptic

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

→