Telescope Comparison
Celestron EdgeHD 11" vs Celestron EdgeHD 8" + CGX
The price gap is real. The question is whether the extra capability is worth it at your stage.
First light
Celestron · 279mm · £4,499
The automated deep-sky platform
- 279mm 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
- 48kg total — requires a fixed garden spot or car transport
Celestron · 203mm · £2,999
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
- 28kg 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 EdgeHD 11" gathers 1.9× 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 EdgeHD 11"'s longer focal length reaches higher magnification with the same eyepiece — better reach for planetary detail. Celestron EdgeHD 8" + CGX'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 EdgeHD 8" + CGX's optical tube is 6.4kg 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 EdgeHD 11" | Celestron EdgeHD 8" + CGX |
|---|---|---|
| Planets | ||
| Moon | Excellent 279mm aperture and 2800mm focal length deliver extraordinary lunar detail — sub-1km features visible in good seeing | Excellent 203mm aperture and f/10 focal ratio deliver superb high-magnification lunar detail — rilles, central peaks, and subtle shadow gradients |
| Saturn | Excellent Cassini Division cleanly split, cloud banding on the disc visible, multiple moons; Encke gap possible in exceptional seeing | Excellent 203mm aperture and 2032mm focal length resolve the Cassini Division, cloud banding on the disc, and multiple moons |
| Jupiter | Excellent Multiple cloud belts with festoons and barges, GRS internal detail, moon shadow transits sharply defined | Excellent Multiple cloud belts, festoons, the Great Red Spot, and Galilean moon shadow transits visible in good seeing |
| Mars | Excellent 279mm aperture and 2800mm focal length exceed the rubric thresholds; dark surface markings, polar caps, and atmospheric features visible at opposition | Good At 203mm, polar cap and dark surface albedo features visible at opposition; benefits from steady seeing at these magnifications |
Deep sky | ||
| Orion Nebula (M42) | Good Trapezium stars cleanly resolved and nebulosity is bright with colour, but 2800mm focal length crops the outer wings — only the core region fits the field | Good Bright core and Trapezium resolved easily, but 2032mm focal length crops the full extent of the nebula — only the central region fits the field |
| Andromeda Galaxy (M31) | Moderate At 2800mm only the bright nuclear region is visible; the full extent of the galaxy vastly overfills the field of view | Moderate At 2032mm focal length, only the bright nucleus and inner core are visible — the outer spiral arms and full extent are well beyond the field of view |
| Open clusters | Moderate Most open clusters overfill the field at 2800mm; compact clusters like M11 fare best, but the Pleiades and Double Cluster are unusable | Moderate Most open clusters overfill the narrow field; compact clusters like M37 work, but the Pleiades and Hyades are far too large |
| Globular clusters | Excellent 279mm resolves individual stars across the full extent of M13, M3, M5 and others; the long focal length provides high magnification naturally | Good 203mm begins to resolve individual stars at the edges of M13 and M3; the high magnification suits these compact targets well |
| Faint galaxies | Excellent 279mm gathers enough light for Hickson groups, interacting pairs, and faint Virgo Cluster members; spiral arm structure visible in brighter galaxies | Good 203mm gathers enough light to reveal structure in brighter galaxies — dust lanes in M104, arms in M51 — and the narrow field suits their small apparent size |
| Milky Way / wide field | Not recommended 2800mm focal length produces far too narrow a field for any wide-field star sweeping | Not recommended 2032mm focal length produces an extremely narrow field — entirely unsuitable for wide-field star sweeping |
Other | ||
| Double stars | Excellent 279mm aperture at f/10 is ideal for double star work; Dawes limit ~0.42 arcseconds splits very tight pairs cleanly | Excellent 203mm aperture at f/10 delivers clean diffraction patterns and high resolving power; tight pairs like Porrima and Albireo are well split |
| Astrophotography (deep sky) | Good GoTo equatorial tracking and flat-field optics are excellent, but f/10 native is slow; the 0.7x reducer (f/7, 1960mm) is practically mandatory for reasonable exposure times | Good Flat-field corrector and equatorial GoTo mount make this a capable deep-sky imager, but native f/10 demands long exposures and precise guiding; the 0.7x reducer brings it closer to Excellent |
| Astrophotography (planetary) | Excellent 279mm aperture at 2800mm native focal length is outstanding for high-resolution planetary video capture with lucky imaging | Excellent 203mm aperture and 2032mm focal length are ideal for high-resolution planetary lucky imaging with a high-speed camera |
The real tradeoff
Both scopes are capable. The question is which one fits the way you actually observe.
Celestron EdgeHD 11"
- You'll wait 60–90 minutes for thermal equilibrium before you can even start a serious imaging session — this is an observatory instrument, and rushing cooldown means bloated stars and wasted subs.
- You'll see structure in Jupiter's Great Red Spot, resolve globulars right across their cores, and pull Hickson compact groups out of the sky — the 279mm aperture delivers views that the 8-inch simply cannot match, and you'll know it the first night you compare the two on M13.
- You'll need a second person to set up, a CGX-L class mount to carry the payload, and a permanent pier to make the whole enterprise sane — this is not a telescope you casually decide to take outside on a clear night.
Celestron EdgeHD 8" + CGX
- You'll spend your first few sessions learning the CGX's polar alignment routine and figuring out collimation, but once dialled in, you have a complete imaging platform out of the box — no separate mount purchase required.
- You'll get sharp, flat-field galaxy images at f/7 with the reducer, but you'll notice you need significantly longer integration times than refractor shooters to overcome the slower focal ratio — patience and clear skies become your most important accessories.
- You'll still groan carrying the 25kg total weight in two trips to the garden, but unlike the 11-inch, one reasonably fit person can actually manage it — this is about as portable as serious long-focal-length imaging gets.
The dark side
Every scope has a personality. Here’s where each one gets difficult.
Celestron
Celestron EdgeHD 11"
The OTA alone weighs approximately 13kg, and with camera, guidescope, and accessories the imaging payload can exceed 17kg — you need a CGX-L or equivalent class mount, which the £4,499 price does not include.
Mirror shift (mirror flop) during imaging sessions causes guiding errors; a mirror lock or off-axis guider is effectively required, adding cost and complexity to every imaging setup.
At 2800mm native focal length, the true field of view is so narrow that extended objects like M31, the Veil Nebula, and large open clusters simply cannot be framed — even with the 0.7x reducer you're still at 1960mm.
Celestron
Celestron EdgeHD 8" + CGX
At 2032mm focal length, autoguiding is non-negotiable for deep-sky imaging — even brief unguided exposures will show star trailing, so budget for a guide camera and guidescope from day one.
The corrector plate dews up aggressively in UK conditions; a dew shield and heater strip are near-mandatory running costs that aren't included in the box.
SCT collimation shifts during transport, so if you're not permanently mounted you'll need to learn star-testing and secondary mirror adjustment — and you'll be doing it regularly.
Which is right for you?
Two different buyers. Two different right answers.
The automated deep-sky platform
Celestron · Celestron EdgeHD 11"
You already have a permanent pier or observatory, you own a CGX-L or EQ6-class mount, and you want the highest-resolution planetary and galaxy imaging available in a commercial SCT. You're chasing detail — festoons on Jupiter, dust lanes in distant galaxies, resolved cores in globular clusters — and you're willing to spend 90 minutes on cooldown and manage a 17kg+ imaging train to get it. This is not your first telescope; it's the one you've been building toward.
The automated deep-sky platform
Celestron · Celestron EdgeHD 8" + CGX
You're stepping into serious long-focal-length astrophotography and you want a complete, mount-included system that can deliver flat-field galaxy and planetary nebula images without buying everything separately. You're comfortable learning collimation, polar alignment, and autoguiding, but you don't yet have a permanent observatory — you're willing to haul 25kg to the garden for a good night. If you want wide-field Milky Way shots or a grab-and-go visual scope, look elsewhere entirely, but if your target list is galaxies, planetaries, and planets, this is a capable and significantly more affordable entry point than the 11-inch.
Our verdict
At £2,999 versus £4,499, the Celestron EdgeHD 11" costs 50% more. It delivers 76mm more aperture — a real and visible advantage on faint targets.
If budget is a genuine constraint, the Celestron EdgeHD 8" + CGX will make you a happy observer. The Celestron EdgeHD 11"'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 EdgeHD 8" + CGX, use it for a year, then upgrade knowing exactly what you want.
Celestron EdgeHD 11"
View Celestron EdgeHD 11" →Celestron EdgeHD 8" + CGX
View Celestron EdgeHD 8" + CGX →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 EdgeHD 11" | Celestron EdgeHD 8" + CGX |
|---|---|---|
Apertureⓘ The most important spec — bigger = more light = better views | 279mm | 203mm |
Focal Length Longer = more magnification potential | 2800mm | 2032mm |
Focal Ratio Lower f-number = wider field of view; higher = more magnification per eyepiece | f/10.04 | f/10 |
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, EdgeHD flat-field corrector | StarBright XLT fully multi-coated, EdgeHD flat-field corrector |
How do you point it?
| Spec | Celestron EdgeHD 11" | Celestron EdgeHD 8" + CGX |
|---|---|---|
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 EdgeHD 11" | Celestron EdgeHD 8" + CGX |
|---|---|---|
Focuser Size 2" accepts wider eyepieces and gives better low-power views | 2" | 2" |
Focuser Type Rack-and-pinion is standard; Crayford and dual-speed are smoother | SCT rear-cell focuser (2" visual back included) | SCT rear-cell focuser (2" visual back included) |
Size & weight
| Spec | Celestron EdgeHD 11" | Celestron EdgeHD 8" + CGX |
|---|---|---|
OTA Weightⓘ Optical tube only — useful for comparing mount load capacity | 11.8kg | 5.4kg |
Total Weightⓘ Full setup including mount — this is what you lug to the car | 48kg | 28kg |
Tube Length | 584mm | 432mm |
Tube Material | Aluminium | Aluminium |
What's in the box?
| Spec | Celestron EdgeHD 11" | Celestron EdgeHD 8" + CGX |
|---|---|---|
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 EdgeHD 11" advantage · Amber highlight: Celestron EdgeHD 8" + CGX advantage · Greyed cells: equal or subjective.