Telescope Types & Comparisons
Refractor vs Reflector: Which Should You Buy?
At the same price a reflector gives you substantially more aperture. A refractor gives you a sealed tube with nothing to maintain. That is the entire trade.
By Scooter M. · Published · How we pick
Buy the reflector if you want to see more. Buy the refractor if you want to maintain nothing. At a given price a reflector gives roughly half again as much aperture, and that is a real difference on anything faint.
The arithmetic behind the trade
light ratio = (aperture 1 / aperture 2) squared
A 130mm reflector against a 102mm refractor: (130 / 102)squared = 1.62
The reflector collects 62 percent more light and resolves 0.89 arcseconds against the refractor's 1.14. Run your own pair through the aperture calculator.
The reason is manufacturing. A mirror needs one surface figured accurately and can be supported across its whole back; a lens needs several precisely figured surfaces in high-quality glass and can only be held at the rim. The cost gap widens quickly with size, which is why large refractors are rare and large reflectors are not.
Pros and cons, side by side
| Refractor | Newtonian reflector | |
|---|---|---|
| Aperture at the same price | Smaller | Larger, by roughly 30 percent |
| Maintenance | None | Occasional collimation, occasional mirror clean |
| Cool-down | Minimal | 20 to 45 minutes |
| Optical flaw to expect | Chromatic aberration, a violet fringe on bright objects | Coma at the field edge on fast tubes |
| Image orientation | Upside down, or mirrored with a diagonal | Upside down |
| Robustness | Sealed tube, nothing to knock out of alignment | Open tube, mirrors can shift |
| Best at | The Moon, planets, double stars, wide star fields | Deep sky, and everything else per dollar |
What chromatic aberration actually looks like
A simple lens brings different colors to focus at slightly different points, so a bright object gets a faint violet fringe. On the Moon's limb and on Venus it is visible; on anything faint it is not, because there is not enough light for the fringe to show.
It is worse in short-focus refractors, which is why an f/10 tube shows less of it than an f/5 one of the same aperture. Apochromatic refractors correct it properly using exotic glass, and they cost several times what a beginner telescope does.
What collimation actually involves
Collimation means aligning the two mirrors of a Newtonian so they point at each other correctly. It takes a few minutes with a cheap tool, it needs doing occasionally rather than every session, and a Dobsonian that lives indoors and is carried gently can go months without needing it.
It is the single most over-feared aspect of owning a reflector. The collimation guide walks through it step by step, and most people find it takes less time than assembling a tripod.
How this is funded: the buy buttons below are Amazon Associates links, and a qualifying purchase earns us a commission at no extra cost to you. It cannot move the ranking, because the order here is set by aperture per dollar, and no commission rate changes how much light a mirror collects. Full disclosure.
| # | Telescope | Best for | Aperture | Price |
|---|---|---|---|---|
| 1 | No image Sky-Watcher Heritage 130 Tabletop DobsonianTop pickThe same 130mm parabolic mirror as scopes costing far more, on a base with no tripod to wobble and nothing to set up. | Most aperture per dollar | 130mm260x useful | Check price#ad |
| 2 | No image Celestron AstroMaster 102AZ102mm of refractor at f/6.5, which means a short tube and a wide field. A no-maintenance scope with real aperture behind it. | Wide-field refractor views | 102mm (4 in)204x useful | Check price#ad |
| 3 | No image Sky-Watcher Classic 200P Dobsonian (8-inch)Eight inches of aperture on the simplest mount ever designed. This is the telescope experienced observers tell beginners to buy. | The one you will not outgrow | 200mm (8 in)400x useful | Check price#ad |
| 4 | No image Celestron AstroMaster LT 70AZ70mm of honest refractor optics at f/10. It will show you Saturn's rings as a small sharp oval, and it will not pretend otherwise. | The smallest scope worth owning | 70mm (2.76 in)140x useful | Check price#ad |
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Top pick · Most aperture per dollar
Sky-Watcher Heritage 130 Tabletop Dobsonian
The same 130mm parabolic mirror as scopes costing far more, on a base with no tripod to wobble and nothing to set up.
What the aperture allows
- Maximum useful magnification
- 260x
- 2 × 130mm of aperture
- Resolving limit (Dawes)
- 0.89 arcseconds
- 116 ÷ 130mm
- Cassini division (0.7″)
- Out of reach
- this aperture cannot resolve it
Worked example: a 25mm eyepiece in this telescope gives 650mm ÷ 25mm = 26x.
This is the aperture-per-dollar champion of the beginner shelf and it is not close. You get the same 130mm parabolic mirror found in telescopes at twice the price, and you get it without paying for a tripod, a slow-motion assembly or a hand controller.
Two times 130mm is 260x of useful magnification. Dawes' limit at 130mm works out to 116 divided by 130, which is 0.89 arcseconds. The Cassini division in Saturn's rings spans roughly 0.7 arcseconds at its widest, so this telescope sits right at the edge of showing it on a still night and will show the rings themselves easily.
The catch is the word tabletop. It needs a surface at roughly chest height when you are seated. A garden table works, a plastic patio chair does not, and buying one without thinking about where it will stand is the single most common regret with this design.
The tube collapses, which is what makes it live in a cupboard rather than a garage. That matters more than it sounds: the telescope you can carry outside in one trip is the telescope you use.
What it does well
- The most aperture you can buy at this price, by a clear margin
- Nothing to assemble, no tripod to wobble, ready in the time it takes to carry it outside
- Collapsible tube stores in a cupboard and keeps its collimation
- The Dobsonian motion is intuitive: you push the tube where you want to look
What it costs you
- Needs a solid table or stool at the right height, which is a real constraint
- The helical focuser is coarser than a rack-and-pinion or a Crayford
- Open tube design collects dust and needs the odd mirror clean
Skip this one if: Skip it if you have nowhere to stand it. On the ground it points at treetops, and on a wobbly plastic table every view shakes.
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Pick 2 · Wide-field refractor views
Celestron AstroMaster 102AZ
102mm of refractor at f/6.5, which means a short tube and a wide field. A no-maintenance scope with real aperture behind it.
What the aperture allows
- Maximum useful magnification
- 204x
- 2 × 102mm of aperture
- Resolving limit (Dawes)
- 1.14 arcseconds
- 116 ÷ 102mm
- Cassini division (0.7″)
- Out of reach
- this aperture cannot resolve it
Celestron publishes 241x as this telescope’s highest useful magnification. Our figure is 204x, from two times the aperture in millimeters. The gap of 37x comes from the slightly more generous per-inch constant makers use. Neither number describes a typical night: the atmosphere usually settles the question well below both.
Worked example: a 25mm eyepiece in this telescope gives 660mm ÷ 25mm = 26x.
102mm collects 2.1 times the light of a 70mm refractor, which is the ratio 102 over 70, squared. That is the difference between the Orion Nebula as a smudge and the Orion Nebula as a shape.
Two times 102mm gives 204x of useful magnification; Celestron publishes 241x. Its published Dawes limit of 1.14 arcseconds is short of the Cassini division, so expect the rings as a clean separated ring rather than a ring with a gap in it.
The short f/6.5 tube is the interesting part. It gives a wide true field for a refractor, which makes large open clusters and Milky Way star fields genuinely rewarding, and it keeps the tube short enough to be easy to handle.
Refractor maintenance is the real selling point for a household that will not enjoy collimating anything. There is nothing to align and nothing to clean.
What it does well
- Real aperture with zero maintenance
- Wide field for a refractor: good on clusters as well as planets
- Short tube balances easily on a simple mount
What it costs you
- A fast achromat shows more color fringing on bright objects than an f/10 tube
- The AZ mount is basic; expect to nudge rather than glide
- Still 102mm, so faint galaxies remain out of reach
Skip this one if: Skip it if the planets are the whole point. A long f/10 refractor or a Dobsonian will show them with less false color.
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Pick 3 · The one you will not outgrow
Sky-Watcher Classic 200P Dobsonian (8-inch)
Eight inches of aperture on the simplest mount ever designed. This is the telescope experienced observers tell beginners to buy.
What the aperture allows
- Maximum useful magnification
- 400x
- 2 × 200mm of aperture
- Resolving limit (Dawes)
- 0.58 arcseconds
- 116 ÷ 200mm
- Cassini division (0.7″)
- Within reach
- on a steady night, at high magnification
200mm is a different category of instrument, not an incremental upgrade. Against the 70mm refractor at the other end of this list the light-gathering ratio is 200 divided by 70, squared: 8.2 times more light reaching your eye.
Two times 200mm gives 400x of useful magnification, which is more than the atmosphere delivers on all but a handful of nights a year. In practice this telescope is limited by the sky rather than by its optics, which is exactly the position you want to be in.
Dawes' limit at 200mm is 116 divided by 200, which is 0.58 arcseconds. The Cassini division, at roughly 0.7 arcseconds, is comfortably inside that. So is the Great Red Spot, and so are hundreds of Messier objects a 70mm scope simply cannot reach.
The honest cost is bulk. The tube is long and the base is wide, and this is a telescope you carry outside in two trips. Everyone who owns one tells the same story: they used it far more once they stopped storing it somewhere awkward.
What it does well
- The aperture-per-dollar figure that no other design at this price approaches
- A mount that cannot be wobbly, because there is almost nothing to it
- The 2-inch focuser takes wide-field eyepieces the cheaper models cannot
- Genuinely a lifetime telescope; nobody outgrows eight inches of aperture in a hurry
What it costs you
- Big and heavy: two trips outside, and it needs real storage space
- No tracking, so at 200x objects drift out of view in well under a minute
- Needs collimation checks, and the mirror takes 30 to 45 minutes to reach outside temperature
Skip this one if: Skip it if you live upstairs with no lift, or if the observing spot is a fire escape. The best telescope in this list is the wrong one if carrying it is a chore.
| Optical design | Newtonian reflector, borosilicate parabolic primary with 94 percent reflective coatingsSource: Classic 200P Dobsonian — manufacturer specifications (retrieved September 1, 2026) |
|---|---|
| Aperture | 200mm (8 in)Source: Classic 200P Dobsonian — manufacturer specifications (retrieved September 1, 2026) |
| Mount | Dobsonian rocker box with Teflon bearings and a patented tension control handleSource: Classic 200P Dobsonian — manufacturer specifications (retrieved September 1, 2026) |
| Light gathering vs the eye | 816xSky-Watcher's own published figure.Source: Classic 200P Dobsonian — manufacturer specifications (retrieved September 1, 2026) |
| Focuser | 2-inch Crayford with a 1.25-inch adapterSource: Classic 200P Dobsonian — manufacturer specifications (retrieved September 1, 2026) |
| Versus the 6-inch model | 78 percent brighter than the 150mm versionSky-Watcher's own published comparison.Source: Classic 200P Dobsonian — manufacturer specifications (retrieved September 1, 2026) |
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Pick 4 · The smallest scope worth owning
Celestron AstroMaster LT 70AZ
70mm of honest refractor optics at f/10. It will show you Saturn's rings as a small sharp oval, and it will not pretend otherwise.
What the aperture allows
- Maximum useful magnification
- 140x
- 2 × 70mm of aperture
- Resolving limit (Dawes)
- 1.66 arcseconds
- 116 ÷ 70mm
- Cassini division (0.7″)
- Out of reach
- this aperture cannot resolve it
Celestron publishes 165x as this telescope’s highest useful magnification. Our figure is 140x, from two times the aperture in millimeters. The gap of 25x comes from the slightly more generous per-inch constant makers use. Neither number describes a typical night: the atmosphere usually settles the question well below both.
Worked example: a 25mm eyepiece in this telescope gives 700mm ÷ 25mm = 28x.
70mm is the floor. Below it a telescope struggles to beat a decent pair of binoculars, and that is a real comparison rather than a rhetorical one.
Two times 70mm gives 140x of useful magnification. Celestron publishes 165x for this tube. Either way, a box on the same shelf advertising 525x is describing an eyepiece swap, not an optical capability.
At f/10 the long focal length does the refractor's classic favor: it is forgiving of cheap eyepieces and it produces high-contrast views of the Moon and the bright planets. Deep-sky objects are mostly beyond it, and it is better to know that going in.
Its published Dawes limit of 1.66 arcseconds means it will not split the tightest doubles or show the Cassini division. It will show the rings, four moons of Jupiter, the phases of Venus, and a lunar terminator that people remember for years.
What it does well
- Sealed tube: no collimation, no mirror cleaning, essentially no maintenance
- Light enough that carrying it outside is never the reason it stays indoors
- The f/10 focal ratio is forgiving of the budget eyepieces it ships with
- Genuinely good on the Moon and the bright planets, which is what most first-timers actually look at
What it costs you
- 70mm collects too little light for galaxies and most nebulae
- The alt-azimuth mount has no slow-motion control on the LT version
- Chromatic aberration puts a faint violet fringe on very bright objects
Skip this one if: Skip it if what you actually want is deep sky. No amount of eyepiece will make 70mm show you a spiral arm.
Questions people actually ask
Which is better, a refractor or a reflector telescope?
Neither in general. At the same price a reflector gives roughly 30 percent more aperture, which is over 60 percent more light. A refractor needs no maintenance and no cool-down. Choose the reflector for what you can see and the refractor for convenience.
Why are reflector telescopes cheaper?
A mirror needs only one surface figured accurately and can be supported across its whole back. A lens needs several precisely figured surfaces in high-quality glass and can only be held at its rim. The cost difference grows quickly with aperture.
Do refractors show sharper images?
At small apertures, often yes, because there is no central obstruction and nothing to misalign. At larger apertures the reflector's extra light and finer resolving limit outweigh that advantage comfortably.
How often do you need to collimate a reflector?
Occasionally rather than routinely. A telescope that lives indoors and is carried carefully can go months. It is worth checking before an important session, and it takes a few minutes with a cheap tool.
Read next
Best aperture per dollar
Dobsonian Telescopes, and Why Experienced Observers Recommend Them
Why a Dobsonian gives the most aperture per dollar, what the design costs you, and which size to buy.
Top pick: Sky-Watcher Classic 200P Dobsonian (8-inch)
Collimation: Aligning a Reflector's Mirrors
What collimation is, how to tell when a reflector needs it, and why it matters far less than beginners fear.
How to Choose a First Telescope
The five questions that decide a first telescope, in the order that matters, with the arithmetic behind each one.
Top pick: Sky-Watcher Heritage 130 Tabletop Dobsonian
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