Celestron SkyMaster Pro ED 20x80 review

The short answer

Only if color fringing specifically bothers you. Every published figure governing how much light reaches your eye is identical to the cheaper non-ED Pro 20x80, because both are 20x on 80mm. The ED adds color correction Celestron does not quantify, and costs 43 percent more weight plus the sight rail.

This is the top of Celestron's SkyMaster range, and reviewing it is unusually straightforward because the model directly below it shares its aperture and magnification exactly. That turns a vague question — is ED glass worth it? — into a narrow one: what, on the published specifications, actually changes?

What ED glass does, and the one number nobody publishes

Different wavelengths of light refract by slightly different amounts through ordinary glass. The practical result in a binocular is chromatic aberration — a faint purple or green edge on high-contrast objects: the limb of the Moon, the disc of Jupiter, a bright star toward the edge of the field. Extra-low dispersion glass uses rare-earth formulations to pull those wavelengths closer to a common focus.

The effect is real and well understood. The problem for a buyer is that it is also the only claim on this spec sheet that cannot be verified from the spec sheet. Celestron describes the ED glass as virtually eliminating chromatic aberration and publishes no figure at all for it: no residual dispersion value, no comparison against the non-ED model, nothing a reader could check or a competitor could dispute.

Three published light figures, and all three are reproducible

Celestron publishes an exit pupil, a twilight factor and a relative brightness for this model. All three are arithmetic on the two numbers in its name, which is worth demonstrating because it shows they are industry conventions rather than measurements of this particular instrument.

• Exit pupil: objective divided by magnification. 80 / 20 = 4.0mm — published as 4.0mm.
• Twilight factor: the square root of magnification times objective. The square root of 20 x 80 = the square root of 1600 = 40 — published as 40.
• Relative brightness: the exit pupil squared. 4 x 4 = 16 — published as 16.

Now apply the same three formulas to the non-ED SkyMaster Pro 20x80. It is also 20x on 80mm, so it returns 4.0mm, 40 and 16 — the same three numbers, to the decimal. Nothing about ED glass changes how much light arrives at your eye. It changes what the light does once it gets there. That is the single most useful thing to understand before spending the difference, and the box does not say it. This model is also the exception in its own tier: on the Pro ED 7x50 and the Pro ED 15x70, where the division gives a non-round figure, the published exit pupil is lower than the formula and lower than the same sheet's relative brightness implies.

Where the two Pro 20x80s actually differ

Four rows move in the ED's favor: the objective glass, a slightly wider field, the explicit IPX7 rating, and a tripod adapter built onto a balance compensation rail rather than bolted on. Three move against it: 37 oz of extra weight, a close focus that lengthens from 66 ft to over 98, and the loss of the reflex sight rail.

The weight is the one that will decide it for most people. 123.2 oz is 7.7 lbs against 5.4 — about 43 percent heavier for exactly the same aperture. At this scale a binocular is already a tripod instrument, so this is not about handholding; it is about whether your tripod head holds it still, and whether it comes along on the drive to a dark site.

The comparison that undermines it

If you have accepted 7.7 lbs, you are close to accepting 8.75, and that is where this model runs into its own sibling.

• SkyMaster 25x100: 140 oz, 100mm objectives — about 14 percent more weight than the Pro ED
• 100 squared over 80 squared = about 1.56 times the light, for that 14 percent

Fifty-six percent more light for fourteen percent more mass is a far better exchange rate than color correction for forty-three percent more mass. That does not make the ED a bad instrument — it is much the better-built of the two, and the 25x100 is water resistant rather than waterproof, plain multi-coated rather than XLT, and focuses each eyepiece separately. But if your reason for tolerating a heavy binocular is to see more, the aperture is where the weight should go.

Still a tripod instrument, and now without a rail

At 20x, every tremor in your hands is multiplied twenty times, and 7.7 lbs settles the question on its own. The built-in adapter sits on a balance compensation rail, which is a genuinely nicer arrangement than a bolt-on bracket because you can slide the binocular to balance it over the tripod head. The tripod itself is not included and a photo tripod that holds a camera steady will visibly tremble under this.

The missing sight rail deserves one more sentence, because it is the kind of omission that only shows up on a cold night. A 3.4 degree field is about seven Moon-widths. Pointing that at a faint galaxy by eye, in the dark, with your head at an awkward angle behind a 7.7 lb instrument, is the hardest part of using one of these — and the cheaper model in the same family ships with the mount for the accessory that solves it. Our binocular tripod adapter guide covers the mounting side.

Quick picks

The Pro ED 20x80 against the two models it has to beat

#	Product	Best for	Price
1	Celestron SkyMaster Pro ED 20x80 The best-corrected glass in the SkyMaster line, with identical light-gathering to the model below it and the heaviest body short of the 25x100.	Someone who already owns a heavy tripod and is bothered by color fringing	$399.95 on Amazon $449.95 · 11% off #ad How we’re funded · price as of October 18, 2026
2	Celestron SkyMaster Pro 20x80 The same aperture, the same magnification, the same published light figures — 37 oz lighter, and it keeps the reflex sight rail the ED drops.	Almost everyone who was considering the ED	$299.99 on Amazon $349.95 · 14% off #ad How we’re funded · price as of October 18, 2026
3	Celestron SkyMaster 25x100 About 1.56 times the light of any 80mm for only about 14 percent more weight than the ED — the better use of mass, if not of money.	Anyone whose answer to more weight is more aperture	$459.99 on Amazon $519.95 · 12% off #ad How we’re funded · price as of October 18, 2026

Rows link to the full write-up further down this page. Prices come from the live price layer only; where there is no live figure the button reads “Check price” rather than showing a number we remembered.

Who this is actually for

That last row is worth saying plainly on a site mostly about children's optics. Nothing in the SkyMaster Pro ED range is a sensible first binocular for a young observer: a handheld 7x50 puts more light into a dark-adapted young eye and needs no mount at all. This page exists because the parent who caught the interest eventually comes looking, not because a 7.7 lb binocular belongs under a tree.

What we did and did not do

We have not handled or looked through this binocular and we do not say otherwise. Every figure above was read from Celestron's own published specification pages for the Pro ED 20x80, the non-ED Pro 20x80 and the 25x100, re-checked on the date at the top of this page, and linked in the sources below. The exit pupil, twilight factor and relative brightness derivations, the weight ratios, the pound conversions and the area-based light ratios are our arithmetic on those published figures, shown in full so you can redo each one.

We have deliberately not estimated how much visible improvement the ED glass delivers. Celestron publishes no figure for it, we have not observed it, and a number invented for that row would be the easiest thing on this page to get away with and the least defensible. Our standing method is on the methodology page.

One availability note, because it affects what you will find when you click: at the time of writing this model is listed out of stock on Celestron's own store while carrying a live offer at the major retailer. That is why our buy button goes where it does, and why the price beside it comes from the live feed on the date shown rather than from us.

The picks in full

Pick 1

Celestron SkyMaster Pro ED 20x80

Someone who already owns a heavy tripod and is bothered by color fringing

The arithmetic

Both of Celestron's own published light figures here are reproducible from the two numbers in the name, which is a useful check that they are conventions rather than measurements. Exit pupil is 80 divided by 20 = 4.0mm, exactly as published. Twilight factor is the square root of 20 x 80 = the square root of 1600 = 40, exactly as published. Relative brightness is the exit pupil squared, 4 x 4 = 16, exactly as published. All three therefore match the non-ED SkyMaster Pro 20x80 to the decimal, because that model is also 20x on 80mm: nothing about ED glass changes how much light arrives. The figure that does change is weight. 123.2 oz is 7.7 lbs, against 86.4 oz for the non-ED Pro 20x80 — the ED version is about 43 percent heavier for the same aperture and the same magnification. For scale against the next model up, the 25x100 gathers about 1.56 times the light (100 squared over 80 squared) for only about 1.14 times the weight, so this is the one SkyMaster where the extra mass buys glass quality rather than aperture.

ED stands for extra-low dispersion. Ordinary glass bends different wavelengths by slightly different amounts, so a bright object can show a faint colored edge — purple or green fringing on the limb of the Moon, on Jupiter, or on a bright star near the field edge. ED glass uses rare-earth formulations to bring those wavelengths closer to a common focus.

That is a real optical effect and it is the entire reason this model exists. The difficulty, for a site that publishes arithmetic, is that Celestron states the benefit without quantifying it. The spec page says the ED glass virtually eliminates chromatic aberration, and publishes no number for it — no figure for residual dispersion, no comparison against the non-ED model. Every other claim on this page we can check; this is the one we cannot.

What we can check is everything around it, and this is where the review gets interesting. Celestron publishes a twilight factor of 40 and a relative brightness of 16. Both are reproducible from the two numbers in the name: the square root of 20 times 80 is the square root of 1600, which is 40; and relative brightness is the exit pupil squared, 4 times 4, which is 16. The exit pupil itself is 80 divided by 20 = 4.0mm, also exactly as published.

Which means all three figures are identical to the non-ED Pro 20x80, because that model is also 20x on 80mm. ED glass does not change how much light arrives. It changes what happens to the light at the edges of the spectrum. That distinction is the whole buying decision here, and nothing on the carton makes it for you.

Build quality is genuinely the best in the line: waterproof to IPX7 and nitrogen filled, fully multi-coated with XLT, BaK-4 porro prisms, a limited lifetime warranty, and a built-in tripod adapter on a balance compensation rail rather than a bolt-on bracket. It also publishes the widest field of the two 80mm Pro models at 3.4 degrees against 3.2 — 178 ft at 1000 yards against 168.

Skip it if

You want more sky rather than cleaner sky. Every published figure that governs how much you can see — exit pupil, twilight factor, relative brightness — is identical to the non-ED Pro 20x80, which is both cheaper and 37 oz lighter. If you have not personally been annoyed by purple fringing on a bright star or the lunar limb, this upgrade is solving a problem you do not have.

Published specifications for the Celestron SkyMaster Pro ED 20x80

Item number	72035
Magnification	20x
Objective diameter	80mm (3.15")
Prisms	BaK-4 porro
Coatings	Fully multi-coated, XLT, with Extra-Low Dispersion (ED) objective glass
Angular field of view	3.4 degrees
Linear field of view	178 ft at 1000 yds (59 m)
Exit pupil	4.0mm (.16")
Eye relief	15.4mm (.61")
Close focus	98.4 ft (30 m)
Interpupillary distance	56mm-72mm (2.20"-2.83")
Diopter adjustment	Plus or minus 3
Twilight factor	40
Relative brightness	16
Weight	123.2 oz (3492 g)
Dimensions	335mm x 230mm x 94mm (13.2" x 9.1" x 3.7")
Tripod adaptable	Yes, built-in adapter on a balance compensation rail
Weather sealing	Waterproof (IPX7), nitrogen filled
Included	Objective lens caps, eyepiece covers, rainguard, neck strap, lens cloth, non-silica desiccant, deluxe nylon case, manual
Warranty	Limited lifetime
What the box does not do	No tripod, and at 7.7 lbs this needs a substantial one rather than a photo tripod — the built-in adapter is a mounting point, not a mount. No reflex sight rail, which the cheaper non-ED Pro 20x80 does include, so there is no provision for a red dot finder on a 3.4 degree field. Celestron describes the ED glass as virtually eliminating chromatic aberration but publishes no figure for it, so the headline benefit of this model is the one thing on its spec sheet that cannot be checked. A 98.4 ft close focus is longer than the non-ED model's 66.2 ft and rules out most daytime use.

Specifications from Celestron — SkyMaster Pro ED 20x80 specifications. We have not handled this one — everything above is the published spec sheet plus our own arithmetic on it.

$399.95 on Amazon

$449.95 · 11% off

#ad How we’re funded · price as of October 18, 2026

Pick 2

Celestron SkyMaster Pro 20x80

Almost everyone who was considering the ED

The arithmetic

The interesting comparison is against the 25x100 above rather than against a hand-held binocular. This is 86.4 oz against 140 — 5.4 lbs against 8.75 — for 80mm objectives against 100mm, which by the square of the ratio is about 64 percent of the light. Both land on the same 4mm exit pupil, because dividing 80 by 20 and 100 by 25 gives the same answer. What the Pro adds over the bigger model is sealing and coatings that Celestron publishes as fully multi-coated with XLT, against plain multi-coated on the 25x100, plus a rail for a red dot finder — which matters more than it sounds, because aiming a 3.2 degree field at a faint object is genuinely hard.

This is the honest recommendation for most readers who arrived looking at the ED, and it is already our best giant binocular pick.

It is 86.4 oz against the ED's 123.2 — 5.4 lbs against 7.7, which is about 43 percent less to hold steady on a tripod head and in a bag. At this weight class that is not a refinement; it is the difference between a binocular that gets carried to a dark site and one that stays in the cupboard.

It also keeps something the ED quietly loses. Celestron lists a detachable reflex sight rail on the non-ED Pro 20x80 and lists no rail at all on the ED. On a 3.2 or 3.4 degree field, aiming at something faint is genuinely the hard part, and a rail that accepts a red dot finder is the standard fix. Paying more to lose it is a strange trade.

What you give up: the XLT coatings are on both, but the ED objective glass is not, and the non-ED publishes a narrower field (3.2 degrees, 168 ft at 1000 yards) and a shorter close focus of 66.2 ft — which is actually the better figure if you ever point it at anything on the ground.

Skip it if

Color fringing on bright objects is specifically what is bothering you, or you need IPX7 rather than just waterproof-and-nitrogen-filled. Those are the two things the ED genuinely adds, and if either is your actual problem the cheaper model will not fix it.

Published specifications for the Celestron SkyMaster Pro 20x80

Item number	72031
Magnification	20x
Objective diameter	80mm (3.15")
Prisms	BaK-4 porro
Coatings	Fully multi-coated, XLT
Angular field of view	3.2 degrees
Linear field of view	168 ft at 1000 yds (56 m)
Exit pupil	4mm (.15")
Eye relief	15.5mm (.61")
Close focus	66.2 ft (20.2 m)
Tripod adaptable	Yes
Weather sealing	Waterproof, nitrogen filled
Also included	Detachable reflex sight rail for an optional red dot finder
Weight	86.4 oz (2449 g)
Warranty	Limited lifetime
What the box does not do	Still too heavy to hold: at 20x and 5.4 lbs this wants a tripod for anything longer than a glance, and no tripod is included. The 4mm exit pupil is narrower than a dark-adapted eye can use, and a 66 ft close focus rules out most daytime use.

Specifications from Celestron — SkyMaster Pro 20x80 specifications. We have not handled this one — everything above is the published spec sheet plus our own arithmetic on it.

$299.99 on Amazon

$349.95 · 14% off

#ad How we’re funded · price as of October 18, 2026

Pick 3

Celestron SkyMaster 25x100

Anyone whose answer to more weight is more aperture

The arithmetic

100mm objectives put this in telescope territory: each side gathers about the same light as the 102mm refractors we review, and the pair gathers roughly twice what a 70mm telescope does. The arithmetic that decides whether you enjoy it is the weight against the magnification. 140 oz is 8.75 lbs, and at 25x every tremor in your hands is multiplied twenty-five times, so this is a tripod instrument in the same way a telescope is — not as a refinement, as a requirement. Objective divided by magnification gives a 4mm exit pupil, narrower than a dark-adapted adult eye, so it is less forgiving of a bright sky than a 7x50.

Put the two side by side and the weight argument turns awkward for the ED. The 25x100 is 140 oz against 123.2 — only about 14 percent heavier — and 100mm objectives gather about 1.56 times the light of 80mm ones by the ratio of their areas.

So if you have already accepted that this is a tripod instrument and that you will carry something heavy, the extra mass buys considerably more sky in the 25x100 than it buys optical polish in the ED. Each 100mm side gathers roughly what a 102mm refractor does. Our full 25x100 review covers the mounting problem, which is the real cost of owning one.

The honest counterweight: it is the least well-built model in the line. Water resistant, not waterproof. Plain multi-coated, not XLT. No rail. Individual eyepiece focus. Its exit pupil is the same 4mm as both 80mm models, because 100 divided by 25 lands on the same number — so extended objects do not look brighter through it, there is simply more aperture resolving more detail and reaching fainter stars.

Which of the three to buy comes down to one question, and we lay all seven SkyMasters out against it on which SkyMaster should you buy.

Skip it if

You need weather sealing or a field wider than 3 degrees. This is water resistant rather than waterproof, uses plain multi-coating rather than XLT, and has individual eyepiece focus, so each side is refocused separately. It is also the heaviest thing in the line at 8.75 lbs.

Published specifications for the Celestron SkyMaster 25x100

Item number	71017
Magnification	25x
Objective diameter	100mm (3.94")
Prisms	BaK-4 porro
Coatings	Multi-coated
Angular field of view	3 degrees
Linear field of view	156 ft at 1000 yds (52 m)
Exit pupil	4mm (.15")
Eye relief	15mm (.59")
Close focus	80 ft (24.4 m)
Focus	Individual eyepiece focus
Tripod adaptable	Yes, integrated tripod adapter rod
Weather sealing	Water resistant
Weight	140 oz (3969 g)
Included	Nylon carrying case, rainguard, lens caps, neck strap
Warranty	Limited lifetime
What the box does not do	No tripod, and the one you own may not be enough — 8.75 lbs at full extension is more than many photo tripods will hold steady. The 80 ft close focus makes it useless for anything terrestrial nearby, individual eyepiece focus means refocusing each side when you change target distance, and water resistant is not waterproof.

Specifications from Celestron — SkyMaster 25x100 specifications. We have not handled this one — everything above is the published spec sheet plus our own arithmetic on it.

$459.99 on Amazon

$519.95 · 12% off

#ad How we’re funded · price as of October 18, 2026