Telescope Comparison
Celestron NexStar 6SE vs Celestron NexStar 8SE
The price gap is real. The question is whether the extra capability is worth it at your stage.
First light
Celestron · 150mm · £999
The automated deep-sky platform
- 150mm schmidt-cassegrain on a computerised mount with motorised tracking
- Good for: Moon, planets, bright nebulae, star clusters, and deep-sky objects
- GoTo system finds any object in its database after initial star alignment — no star atlas needed
- Tracking motors keep objects centred as Earth rotates — useful above 100×, essential for photography
- 11.5kg total — requires a fixed garden spot or car transport
Celestron · 203mm · £1,860
The automated deep-sky platform
- 203mm schmidt-cassegrain on a computerised mount with motorised tracking
- Good for: Moon, planets, bright nebulae, star clusters, and deep-sky objects
- GoTo system finds any object in its database after initial star alignment — no star atlas needed
- Tracking motors keep objects centred as Earth rotates — useful above 100×, essential for photography
- 18kg total — requires a fixed garden spot or car transport
The full picture
The numbers that separate these two scopes — and what they mean at the eyepiece.
Aperture
Celestron NexStar 8SE gathers 1.8× more light. On bright targets — Moon, Saturn, Jupiter — you won't notice. On fainter targets — dim galaxies, faint globular clusters — the gap is real.
Focal length
Celestron NexStar 8SE's longer focal length reaches higher magnification with the same eyepiece — better reach for planetary detail. Celestron NexStar 6SE's shorter focal length gives a wider true field — better for large open clusters and extended nebulae.
Focal ratio
Same focal ratio — the same eyepiece gives equivalent magnification and true field in both scopes.
Mount type
Same mount type — setup experience and ergonomics will be similar. Differences lie in build quality and included accessories.
Weight (OTA)
Celestron NexStar 6SE's optical tube is 1.9kg lighter. Relevant if you plan to use it on multiple mounts or carry the tube to dark-sky sites separately.
Optical design
Both Schmidt-Cassegrain designs — versatile, compact, good for planets and deep-sky. Differences come from aperture and mount.
At the eyepiece
| Target | Celestron NexStar 6SE | Celestron NexStar 8SE |
|---|---|---|
| Planets | ||
| Moon | Excellent 150mm aperture and f/10 focal ratio reward high magnification — craterlets, rilles, and sharp terminator shadows are all accessible | Excellent 203mm aperture at f/10 is ideal for high-magnification lunar detail — craterlets, rilles, and terminator shadow features are crisp and rewarding |
| Saturn | Excellent 150mm and 1500mm focal length put Cassini Division, ring shadow, and disc banding within reach in steady seeing | Excellent 203mm aperture and 2032mm focal length put this firmly in the top tier — Cassini Division, ring shadow, and cloud banding visible in good seeing |
| Jupiter | Excellent Multiple cloud belts, Great Red Spot, and moon shadow transits visible; 1500mm focal length gives a generously sized disc | Excellent Multiple cloud belts, the Great Red Spot, and Galilean moon shadow transits are all accessible at 200×–300× |
| Mars | Good Polar cap and major dark albedo features visible at opposition; 150mm is below the 200mm threshold for truly detailed Mars observation | Good 203mm aperture resolves dark albedo features and polar caps at opposition; focal length supports high magnification but aperture is just short of the 'Excellent' threshold |
Deep sky | ||
| Orion Nebula (M42) | Good Bright nebulosity and Trapezium are impressive, but the 1500mm focal length crops the full extent of the nebula; f/10 doesn't favour wide-field context | Good Bright core and Trapezium are vivid, but 2032mm focal length restricts the field — you see the central region only, not the full nebula extent |
| Andromeda Galaxy (M31) | Moderate 1500mm focal length frames only the bright core — the outer halo and full disc extend well beyond the field even with a wide eyepiece | Moderate 2032mm focal length shows only the bright nucleus and inner core — the outer halo and dust lanes are cropped well beyond the field of view |
| Open clusters | Moderate Larger clusters like the Pleiades and Double Cluster overfill the field; works better on compact clusters like M35 or M11 | Moderate The very narrow field of view means most open clusters overfill the eyepiece; individual stars are sharp but the cluster context is lost |
| Globular clusters | Good M13 and M5 show granular texture with partial star resolution at the edges; 150mm is below the threshold for full resolution across the cluster | Excellent 203mm aperture resolves individual stars across the outer regions of M13, M22, and similar globulars; the long focal length magnifies them beautifully |
| Faint galaxies | Good 150mm gathers enough light to show structure in brighter galaxies like M51 and M104; fainter targets appear as dim smudges | Good 203mm gathers enough light to show structure in brighter galaxies (M81, M82, M51) and detect fainter ones as diffuse smudges |
| Milky Way / wide field | Not recommended 1500mm focal length gives far too narrow a field for sweeping Milky Way views — this scope is the opposite of a wide-field instrument | Not recommended 2032mm focal length gives far too narrow a field — this scope cannot produce sweeping star field views |
Other | ||
| Double stars | Excellent 150mm aperture and f/10 focal ratio produce clean Airy discs — excellent for splitting close pairs and showing colour contrast | Excellent 203mm aperture at f/10 is textbook for splitting close doubles — clean diffraction pattern and high magnification potential |
| Astrophotography (deep sky) | Moderate Alt-az GoTo mount causes field rotation limiting exposures to a few seconds; usable for EAA and short-exposure stacking but not long-exposure imaging | Moderate GoTo tracking is present but the alt-az mount introduces field rotation, limiting exposures to ~15–30 seconds; an equatorial wedge or EAA live stacking improves results |
| Astrophotography (planetary) | Good 1500mm focal length and tracking mount suit lucky-imaging with a planetary camera; 150mm aperture gives solid detail but falls short of 200mm+ scopes | Excellent 203mm aperture and 2032mm focal length are ideal for high-resolution lucky imaging of planets; the GoTo mount tracks well enough for video capture |
The real tradeoff
Both scopes are capable. The question is which one fits the way you actually observe.
Celestron NexStar 6SE
- You'll carry less weight to your observing spot and set up faster — the 6SE is noticeably lighter and more compact, and on a cold night that difference in portability is the difference between going out and staying in.
- You'll see Jupiter's belts and the Cassini Division clearly, and you'll split tight doubles like Porrima beautifully at f/10, but when you push to fainter deep-sky targets you'll notice you're running out of light-gathering power before you run out of sky — M13 looks granular but doesn't fully resolve, and faint galaxies remain soft smudges.
- You'll save £400 at the eyepiece, and that budget goes a long way toward the 2-inch visual back the scope doesn't include, a wider eyepiece, or a decent planetary filter set — accessories that meaningfully improve what you'll actually see through this scope.
Celestron NexStar 8SE
- You'll wait longer for cool-down — 30 to 60 minutes on a cold night — and you'll learn to set up early and do your GoTo alignment while the tube reaches thermal equilibrium, because until it does, planetary views look like you're observing through a heat shimmer.
- You'll see the payoff of that extra 53mm of aperture most clearly on deep-sky: globular clusters like M13 start genuinely resolving individual stars at the edges rather than just looking grainy, and compact galaxies show hints of real structure that the 6SE can only suggest.
- You'll feel the single-arm mount's limits more acutely — heavier accessories and the bigger tube mean more flex and longer vibration damping, so you'll develop a habit of not touching the focuser and waiting a beat before looking after any adjustment.
The dark side
Every scope has a personality. Here’s where each one gets difficult.
Celestron
Celestron NexStar 6SE
The single-arm fork mount vibrates for 2–3 seconds after every focus touch — at 200× on Saturn, that's an eternity of wobbling image before you can judge the view.
No 2-inch visual back is included, and the stock 1.25-inch setup with the supplied 25mm Plössl gives you only a 0.8° true field at 60× — even with GoTo finding your target, centering and framing feels claustrophobic until you buy the adapter and a wider eyepiece.
The enclosed SCT tube needs 30–45 minutes to cool down in cold weather; thermal currents visibly degrade planetary sharpness until equilibrium, so your first half-hour of observing is wasted on high-magnification targets.
Celestron
Celestron NexStar 8SE
The sealed 8-inch tube takes 30–60 minutes to cool down — longer than the 6SE — and until it does, your planetary views are noticeably soft from internal thermal currents, which is especially painful given that planets are this scope's best trick.
The single-arm fork mount flexes under heavy accessories like binoviewers or cameras, and that flex translates directly into vibration at high magnification — the bigger tube amplifies the mount's weaknesses compared to the lighter 6SE.
The alt-az GoTo mount causes field rotation during tracking, limiting deep-sky exposures to roughly 15–30 seconds before star trails appear — if you're hoping to grow into astrophotography, this mount is a dead end beyond EAA and quick planetary captures.
Which is right for you?
Two different buyers. Two different right answers.
The automated deep-sky platform
Celestron · Celestron NexStar 6SE
You'll love the 6SE if you're an intermediate observer stepping up from a small refractor or tabletop scope who wants serious planetary and lunar detail with GoTo convenience but doesn't want to spend more than £1,000. You observe from a suburban balcony or small garden, portability matters to you, and your main targets are planets, the Moon, double stars, and bright compact deep-sky objects like globulars and planetary nebulae. This isn't for you if you dream of sweeping the Milky Way in wide-field views, want to do long-exposure deep-sky astrophotography, or find a few minutes of GoTo alignment too fussy for a weeknight session.
The automated deep-sky platform
Celestron · Celestron NexStar 8SE
You'll love the 8SE if you want the most aperture you can realistically carry in one trip and you're willing to pay £400 more — and wait longer for cool-down — to get noticeably more detail on globular clusters, compact galaxies, and planetary nebulae alongside excellent planetary views. You're an intermediate observer who values GoTo tracking and may want to explore electronic-assisted astronomy with live stacking. This isn't for you if you're a beginner looking for a simple first scope on a budget, if you want wide-field views of large nebulae and open clusters, or if long-exposure deep-sky imaging is your end goal — the alt-az mount and field rotation will frustrate you before you ever get a usable frame.
Our verdict
At £999 versus £1,860, the Celestron NexStar 8SE costs 86% more. It delivers 53mm more aperture — a real and visible advantage on faint targets.
If budget is a genuine constraint, the Celestron NexStar 6SE will make you a happy observer. The Celestron NexStar 8SE's optical advantage on faint targets is real and you are unlikely to regret it if you can stretch. If I had to choose without knowing your situation: start with the Celestron NexStar 6SE, use it for a year, then upgrade knowing exactly what you want.
Celestron NexStar 6SE
View Celestron NexStar 6SE →Celestron NexStar 8SE
View Celestron NexStar 8SE →Deep field: Full specifications
Every data point, for those who want to go further.
Full specifications
Fields highlighted in blue or amber indicate the better value for that spec. Data is manufacturer-stated and may vary.
How much can it see?
| Spec | Celestron NexStar 6SE | Celestron NexStar 8SE |
|---|---|---|
Apertureⓘ The most important spec — bigger = more light = better views | 150mm | 203mm |
Focal Length Longer = more magnification potential | 1500mm | 2032mm |
Focal Ratio Lower f-number = wider field of view; higher = more magnification per eyepiece | f/10 | f/10.01 |
Optical Design The type of optics — each design has different strengths | Schmidt-Cassegrain | Schmidt-Cassegrain |
Coatings Better coatings = more light transmission through the optics | StarBright XLT fully multi-coated on all optical surfaces | StarBright XLT fully multi-coated on all optical surfaces |
How do you point it?
| Spec | Celestron NexStar 6SE | Celestron NexStar 8SE |
|---|---|---|
Mount Type The mechanical system that holds and moves the telescope | GoTo (Computerised) | GoTo (Computerised) |
GoTo Computer-controlled pointing — finds any of thousands of objects automatically | ||
Tracking Motor keeps objects centred as the Earth rotates — essential for astrophotography |
The focuser
| Spec | Celestron NexStar 6SE | Celestron NexStar 8SE |
|---|---|---|
Focuser Size 2" accepts wider eyepieces and gives better low-power views | 1.25" | 1.25" |
Focuser Type Rack-and-pinion is standard; Crayford and dual-speed are smoother | SCT rear-cell focuser | SCT rear-cell focuser |
Size & weight
| Spec | Celestron NexStar 6SE | Celestron NexStar 8SE |
|---|---|---|
OTA Weightⓘ Optical tube only — useful for comparing mount load capacity | 3.5kg | 5.44kg |
Total Weightⓘ Full setup including mount — this is what you lug to the car | 11.5kg | 18kg |
Tube Length | 394mm | 432mm |
Tube Material | Aluminium | Aluminium |
What's in the box?
| Spec | Celestron NexStar 6SE | Celestron NexStar 8SE |
|---|---|---|
Eyepieces Included eyepieces — more is better, but quality matters more than quantity | 25mm Plössl | 25mm Plössl |
Finder Scope Helps you locate areas of the sky before switching to the main eyepiece | StarPointer red dot finder | StarPointer red dot finder |
Diagonal Tilts the eyepiece 90° for comfortable viewing — useful on refractors |
Blue highlight: Celestron NexStar 6SE advantage · Amber highlight: Celestron NexStar 8SE advantage · Greyed cells: equal or subjective.