Binoculars
Celestron SkyMaster Pro 20x80 review
The giant binocular that a normal tripod can carry, with the one feature the bigger model forgets.
By Scooter M. · published September 27, 2026
I'm not an astronomer and I don't have a lab. I'm someone who's genuinely into this — I read the manuals, compile the published specs, and do the arithmetic the box doesn't do for you. No lab coat. How we pick.
How this is funded. Lens & Lightyear earns a commission when you buy through a link on this page, at no extra cost to you. It does not change which products we pick or what we say about them — every card below carries a real reason to skip it. Prices are pulled live and were last verified October 18, 2026. Full disclosure.
The short answer
This is the giant binocular to buy first. It gathers about 64 percent of the light of the 25x100 at 62 percent of the weight, adds waterproofing and better coatings, and carries the Pro tier's rail for a red dot finder. It still needs a tripod.
There is one model above this in the line: the Pro ED 20x80, which adds extra-low dispersion glass for about 43 percent more weight and publishes the same exit pupil, twilight factor and relative brightness as this one. Giant binoculars fail for two reasons: people cannot hold them, and people cannot aim them. Only the two Pro models in Celestron's SkyMaster family address the second problem, with a rail that accepts a red dot finder. Which of the seven to buy is worked through on which SkyMaster should you buy.
The aiming problem nobody warns you about
A 3.2 degree field sounds generous until you try to put it on something specific. The sky is 180 degrees across; a faint galaxy has no signpost; and unlike a telescope, a binocular usually has no finder at all.
Celestron's answer here is a detachable reflex sight rail — the same idea as the red dot finder on a telescope. Add one and the binocular becomes pointable; without it you are sweeping and hoping, which is fine for the Milky Way and frustrating for a target.
Where the specifications actually differ
| SkyMaster Pro 20x80 | SkyMaster 25x100 | |
|---|---|---|
| Objectives | 80mm | 100mm |
| Light gathered | about 64% of the 25x100 | 100% (the baseline here) |
| Exit pupil | 4mm | 4mm |
| Angular field | 3.2 degrees | 3 degrees |
| Linear field at 1000 yds | 168 ft | 156 ft |
| Eye relief | 15.5mm | 15mm |
| Coatings | Fully multi-coated, XLT | Multi-coated |
| Sealing | Waterproof, nitrogen filled | Water resistant |
| Finder rail | Yes, detachable | No |
| Weight | 86.4 oz (5.4 lbs) | 140 oz (8.75 lbs) |
Celestron's published specifications for items 72031 and 71017. Light ratio is our arithmetic: 80 divided by 100, squared.
Note the exit pupil row. Both land on exactly 4mm, because 80 divided by 20 and 100 divided by 25 give the same answer — so the bigger pair is not *brighter* per unit of image, it simply resolves more detail and reaches deeper.
Quick picks
The Pro 20x80 against its siblings
| # | Product | Best for | Price |
|---|---|---|---|
| 1 |  Celestron SkyMaster Pro 20x80 80mm objectives, 4mm exit pupil, waterproof, XLT coated, with a rail for a red dot finder. | Anyone who wants giant-binocular views without giant-binocular problems | |
| 2 |  Celestron SkyMaster 25x100 100mm objectives and a 3 degree field, at 8.75 lbs. | Maximum light, if your mount can take it | |
| 3 |  Celestron SkyMaster 15x70 70mm at 15x with a 4.7mm exit pupil — the widest pupil of the three. | The lightest way into the family |
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.
Still a tripod instrument
Five and a half pounds at 20x is not hand-holdable for observing, however good your intentions. Tremor is magnified twenty times, and the weight guarantees your arms give out before your patience does.
- Capacity first. 5.4 lbs is within reach of a decent photo tripod, unlike the 25x100's 8.75 lbs. That is the practical argument for this model.
- Height second. Astronomy means looking up. A tripod that reaches your standing eye level saves your neck — see our tripod adapter guide.
- A reclining chair is the cheat code. Lying back with the binocular on a mount, or even braced on a cushion, beats standing for overhead targets.
Who this is for
| Situation | Verdict |
|---|---|
| You want giant binoculars and own a normal tripod | Buy it. The best balance in the family. |
| Dew or damp evenings are normal where you live | Buy it. It is the sealed one. |
| You want the deepest views and own a heavy mount | The 25x100. |
| You are not sure giant binoculars are for you | The 15x70 first. |
| Hand-held is a requirement | A 7x50 or 10x50 — nothing this size is hand-held. |
| A child is the user | No. See binoculars by age. |
What we did and did not do
We have not handled these binoculars. Every specification above was read from Celestron's own published pages for items 72031 and 71017, linked below and checked on the date at the top of this page. The light ratio and exit pupil figures are arithmetic on those specifications.
No price appears in this prose. Live figures come only from our price feed with the date they were checked. Our full method is on the methodology page.
The picks in full
Pick 1
Celestron SkyMaster Pro 20x80
Anyone who wants giant-binocular views without giant-binocular problems
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 giant binocular we would buy, and the reasons are all in specifications the bigger model does not match.
Sealing: Celestron publishes waterproof and nitrogen filled here, against *water resistant* on the 25x100. Dew is the standard enemy of an evening outdoors, and a sealed instrument survives it.
Coatings: fully multi-coated with Celestron's XLT treatment, against plain multi-coated on the bigger pair. More of the light that enters reaches your eye.
The finder rail: a detachable reflex sight rail for an optional red dot finder. Aiming a 3.2 degree field at a faint object is the real difficulty with any giant binocular, and this is the only one in the family that offers a fix.
The honest costs: 80mm gathers about 64 percent of what 100mm does, 15.5mm of eye relief is tight in glasses, the 66 ft close focus rules out daytime use, and no tripod is included.
Skip it if
You expect to hand-hold it. At 86.4 oz — 5.4 lbs — and 20x, this still needs a tripod for anything beyond a brief look.
| 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.
Pick 2
Celestron SkyMaster 25x100
Maximum light, if your mount can take it
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.
The bigger sibling gathers about 56 percent more light, which under a dark sky is a real and visible step on faint objects.
What it asks in return is a serious mount: 8.75 lbs at 25x is beyond what many tripods hold steady, and there is no rail to add a finder.
If you observe from a fixed spot with a heavy tripod already in the garage, it is the more capable instrument. Full review.
Skip it if
Your tripod is an ordinary photo tripod, or dew is common where you observe — it is water resistant rather than waterproof, and it has no finder rail.
| 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.
Pick 3
Celestron SkyMaster 15x70
The lightest way into the family
The arithmetic
The counter-intuitive number: 70 / 15 = 4.7mm exit pupil, against 7.1mm for a 7x50. More objective glass, but spread across more magnification — so into a child's fully dark-adapted 7mm pupil this delivers roughly (4.7 / 7.1) squared, about 44 percent of the light the cheaper 7x50 does. The 70mm advantage is real only for an adult eye that no longer dilates past 5mm, or on a tripod where the extra reach pays. At 48 oz it is 1.76 times the weight of a 7x50 and 15x magnifies hand tremor fifteen times: this is a tripod instrument, not a handheld one.
The entry point, at roughly 3 lbs, and the only one in the family that can be lifted briefly by hand without the view swimming.
Its 4.7mm exit pupil is the widest here, which makes it slightly more forgiving under a dark sky than either 4mm model.
It is also the cheapest way to discover whether two-eyed observing suits you. Full review.
Skip it if
You want the extra aperture and already plan to mount it. 70mm against 80mm is about 77 percent of the light.
| Magnification | 15x |
|---|---|
| Objective lens | 70mm (2.75") |
| Prism glass | BaK-4 |
| Lens coatings | Multi-coated |
| Angular field of view | 4.4 degrees |
| Linear field at 1000 yds | 231 ft (77 m) |
| Exit pupil | 4.7mm (.18") |
| Eye relief | 18mm (.71") |
| Close focus | 43 ft (13 m) |
| Weight | 48 oz (1361 g) |
| Tripod adaptable | Yes |
| Environmental | Water resistant |
| What the box does not do | No tripod and no tripod adapter in the box, and it genuinely needs both — 48 oz at 15x cannot be held steady by anyone, let alone a child. Water resistant, not waterproof. A 43 ft close focus rules out any daytime use in a garden. |
Specifications from Celestron — SkyMaster 15x70 specifications. We have not handled this one — everything above is the published spec sheet plus our own arithmetic on it.
Questions people actually ask
- Are the SkyMaster Pro 20x80 binoculars worth it over the standard SkyMaster?
- For the sealing and coatings, yes. The Pro line is waterproof and nitrogen filled with fully multi-coated XLT optics, where the standard SkyMasters are water resistant with plain multi-coating. The Pro 20x80 also has a detachable rail for a red dot finder.
- Can you hold 20x80 binoculars by hand?
- Not for observing. At 86.4 oz — 5.4 lbs — and 20x magnification, hand tremor is multiplied twenty times and your arms tire quickly. A tripod is needed, though a normal photo tripod can usually carry this pair where it cannot carry a 25x100.
- How do you aim giant binoculars at a faint object?
- With a finder or from a known star. This model has a detachable reflex sight rail for an optional red dot finder, which is the only such fitting in Celestron's SkyMaster family. Otherwise, sweep from a bright signpost star rather than from nothing.
- What is the exit pupil of 20x80 binoculars?
- 4mm — the objective divided by the magnification. That is narrower than a dark-adapted adult pupil, so under a bright sky a 7x50 with its 7.1mm exit pupil looks more forgiving, while under a dark sky the 80mm aperture shows far more.
- Are these good for daytime use?
- Not really. The close focus is 66.2 ft, so nothing nearby will focus, and 5.4 lbs at 20x is unwieldy for wildlife. A 42mm roof prism pair is the right tool for daylight.
Sources
Read next
Where to go from here
- Celestron SkyMaster Pro ED 20x80 review
Top of the SkyMaster line. Every published light figure matches the cheaper Pro 20x80 exactly, because it is the same 20x on the same 80mm — so what you are buying is color correction, for 43 percent more weight and no sight rail.
- Celestron SkyMaster 25x100 review
100mm per side puts this in telescope territory, and 8.75 lbs at 25x puts it permanently on a tripod. The arithmetic on what that buys, and what it costs.
- Celestron SkyMaster 15x70 review
The big-binocular option, reviewed honestly: 70mm objectives that deliver less light to a dark-adapted child's eye than a 7x50, and 48 oz that demand a tripod.
- Which Celestron SkyMaster should you buy?
12x60, 15x70, 25x70, 20x80, Pro 15x70, Pro 20x80 or 25x100? Compared on Celestron's own published figures, with the exit-pupil arithmetic that separates them.
- Putting binoculars on a tripod: adapter, tripod, and the height nobody checks
The cheapest fix for the most common binocular disappointment. Which binoculars accept an adapter, what tripod height actually matters for looking up, and what this will not fix.
- The best binoculars for stargazing with kids
The exit pupil calculation that decides which binoculars suit a child, and what a 7x50 actually shows on a first clear night.
- The best stargazing binoculars under $100
Three pairs under $100, judged on exit pupil, prism glass and steadiness rather than on magnification claims — plus the two corners this budget always cuts.
- The best telescope for deep space
Galaxies and nebulae are won with aperture and dark skies, never magnification. What limiting magnitude means in practice, and the telescopes that reach deepest here.