Telescope Comparison
Celestron StarSense Explorer DX 102AZ vs Sky-Watcher Evostar 72ED
The Celestron StarSense Explorer DX 102AZ is a complete setup. The Sky-Watcher Evostar 72ED needs a mount before it's usable.
First light
Celestron · 102mm · £229
The simple alt-az visual scope
- 102mm refractor on a simple alt-az mount
- Good for: Moon, planets, bright open clusters
- No alignment required — quick to set up, intuitive to move
- Finding objects requires learning to star-hop: navigate with a finder scope and sky chart
- 7.5kg total — manageable to carry to dark-sky sites
Sky-Watcher · 72mm · £199
The custom-rig optical tube
- 72mm refractor — optical tube only, no mount included
- 420mm focal length at f/5.83
- Requires a compatible mount before you can observe anything
- Best for: observers who already own a suitable mount or are building a specific imaging rig
- Not a complete purchase — budget at least £100–300 extra for a mount before observing
The full picture
The numbers that separate these two scopes — and what they mean at the eyepiece.
Aperture
Celestron StarSense Explorer DX 102AZ gathers 2× 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 StarSense Explorer DX 102AZ's longer focal length reaches higher magnification with the same eyepiece — better reach for planetary detail. Sky-Watcher Evostar 72ED's shorter focal length gives a wider true field — better for large open clusters and extended nebulae.
Focal ratio
Sky-Watcher Evostar 72ED's faster f/5.83 delivers wider fields with any eyepiece — better for open clusters and large nebulae. Celestron StarSense Explorer DX 102AZ's f/6.47 provides more magnification per eyepiece — better for fine planetary detail.
Mount type
Sky-Watcher Evostar 72ED has no mount — add a compatible mount before you can observe. Celestron StarSense Explorer DX 102AZ is a complete ready-to-use system.
Weight (OTA)
Sky-Watcher Evostar 72ED's optical tube is 1.8kg lighter. Relevant if you plan to use it on multiple mounts or carry the tube to dark-sky sites separately.
Optical design
Both are refractors — no mirrors to collimate, good contrast, colour-free stars with ED or APO glass. The differences between them are in aperture, focal ratio, and glass quality.
At the eyepiece
| Target | Celestron StarSense Explorer DX 102AZ | Sky-Watcher Evostar 72ED |
|---|---|---|
| Planets | ||
| Moon | Excellent 102mm aperture delivers sharp crater detail, rilles, and mountain shadows; chromatic aberration adds a purple fringe at high power but doesn't obscure detail | Moderate 72mm aperture shows craters and terminator detail, but short focal length (420mm) means high magnification requires very short eyepieces; ED glass gives clean, colour-free views |
| Saturn | Good Rings clearly defined at 100–130×, Cassini Division visible in steady seeing; 660mm focal length limits magnification headroom without a Barlow | Moderate Rings visible and disc discernible at 70–100×, but Cassini Division needs excellent seeing; 420mm focal length keeps the image small |
| Jupiter | Good Two main cloud belts and Galilean moons easily seen; some chromatic aberration softens fine detail at higher magnifications | Moderate Disc and two main equatorial belts visible, but fine banding and GRS detail require more aperture and focal length |
| Mars | Moderate Small orange disc visible at opposition with hints of the polar cap; 102mm aperture and 660mm focal length limit surface detail | Challenging Small orange disc visible at opposition; polar cap may be glimpsed in excellent seeing but surface detail is beyond this aperture |
Deep sky | ||
| Orion Nebula (M42) | Excellent 102mm gathers enough light for bright nebulosity and the Trapezium; 660mm focal length frames the full nebula extent well | Good Short focal length frames the full nebula complex nicely; 72mm shows the bright core and surrounding nebulosity but fainter wisps need more aperture |
| Andromeda Galaxy (M31) | Excellent 660mm focal length captures the bright core and inner halo in a single field; 102mm aperture helps reveal outer structure from dark sites | Excellent 420mm focal length captures the full extent of M31 including companion galaxies; visually the core is bright but outer arms need dark skies |
| Open clusters | Excellent 660mm focal length gives wide enough true fields to frame the Pleiades, Double Cluster, and other showpiece clusters | Excellent Wide field of view at 420mm is ideal — Pleiades, Double Cluster, and M35 are beautifully framed with surrounding star context |
| Globular clusters | Moderate M13 and M22 appear as bright, grainy balls; 102mm cannot resolve individual stars across the cluster | Challenging 72mm cannot resolve individual stars; M13 and M3 appear as fuzzy, unresolved glows |
| Faint galaxies | Moderate Brighter Messier galaxies like M81/M82 visible as faint smudges; limited by 102mm light grasp | Challenging 72mm aperture limits detection to only the brightest galaxies; most appear as faint smudges or are invisible |
| Milky Way / wide field | Good 660mm focal length is slightly long for true sweeping panoramas but still delivers pleasant rich-field views of star clouds | Excellent 420mm at f/5.8 is a natural wide-field instrument — sweeping Milky Way star fields and large-scale structures are this scope's visual sweet spot |
Other | ||
| Double stars | Excellent 102mm cleanly splits Albireo, Mizar, and wider doubles; close pairs below 1.5" are limited by chromatic aberration at f/6.5 | Good 72mm resolves wider doubles like Albireo cleanly with good colour; closer pairs below ~2 arcseconds are beyond the Dawes limit |
| Astrophotography (planetary) | Not applicable | Challenging 72mm aperture and 420mm focal length produce a very small planetary image scale; a Barlow helps but cannot overcome the aperture limit |
| Wide-field astrophotography (nebulae and Milky Way) | Not applicable | Excellent This is the scope's primary design purpose — fast focal ratio, ED glass, and compact size pair perfectly with a star tracker for large emission nebulae, Milky Way panels, and galaxy fields |
The real tradeoff
Both scopes are capable. The question is which one fits the way you actually observe.
Celestron StarSense Explorer DX 102AZ
- You'll unbox this, mount your phone, and be staring at Saturn's rings within fifteen minutes — the StarSense app plate-solves the sky in real time and literally draws an arrow to your target, which means you'll visit more objects in your first evening than most beginners find in a month.
- At 102mm you have enough aperture to make the Moon genuinely exciting — crater walls, shadow detail along the terminator, even the Cassini Division on a steady night — but you'll learn to live with a persistent purple fringe around anything bright, because that's what a fast achromat does.
- Every object drifts out of your eyepiece in under a minute at higher powers, and you'll spend half your time nudging a slightly stiff alt-az mount back on target instead of just looking — there's no motor drive, so the experience is guided finding followed by manual tracking.
Sky-Watcher Evostar 72ED
- You'll open the box and find a beautifully compact OTA — and nothing else; no mount, no diagonal, no eyepieces, no finder — so your first session doesn't happen until you've budgeted another £200–£400 for a star tracker or EQ mount plus accessories.
- Your real reward comes when you attach a DSLR or mirrorless camera: the ED glass delivers tight, colour-corrected stars across a huge 3°+ field, and even 30-second tracked exposures will pull pink nebulosity out of Orion or reveal the full extent of Andromeda in a way no visual scope at this price can match.
- If you do point this at Jupiter or the Moon with an eyepiece, you'll see a small, clean disc with noticeably less chromatic aberration than the StarSense's achromat — but 72mm of aperture runs out of resolution fast, and you'll feel the limits long before the Celestron does on planets.
The dark side
Every scope has a personality. Here’s where each one gets difficult.
Celestron
Celestron StarSense Explorer DX 102AZ
Chromatic aberration is baked into the f/6.5 achromat design — expect a visible purple halo around the Moon's limb and Jupiter that no filter fully removes.
The StarSense system depends on your smartphone's rear camera for plate-solving; older or budget phones can struggle in light-polluted skies, and if your phone isn't compatible, the scope's signature feature is gone.
The kit eyepieces are basic Kellners with short eye relief at higher powers — you'll likely want to replace them quickly, and the alt-az mount's slightly jerky fine-adjustment feel makes high-magnification tracking more frustrating than it should be.
Sky-Watcher
Sky-Watcher Evostar 72ED
The OTA-only package at £199 is deceptive — by the time you add a mount, diagonal, finder, and eyepieces, your total spend can easily exceed £400–£500, making it significantly more expensive than the Celestron's ready-to-observe £229.
Without a dedicated field flattener (sold separately), stars toward the edges of your camera sensor will show noticeable curvature and elongation, undermining the very imaging performance you bought this scope for.
The stock rack-and-pinion focuser can flex under the weight of a DSLR and accessories, which introduces star trailing in long exposures — many owners end up upgrading to a Crayford-style focuser to get the imaging rigidity the optics deserve.
Which is right for you?
Two different buyers. Two different right answers.
The simple alt-az visual scope
Celestron · Celestron StarSense Explorer DX 102AZ
You're new to astronomy, you want to look through an eyepiece tonight, and your biggest fear is spending an hour squinting at a star chart and never finding anything. You want the Moon to look spectacular, you want to spot Saturn's rings and Jupiter's belts with your own eyes, and you want a complete grab-and-go kit that the whole family can use without collimation or laptop software. You don't care about astrophotography beyond a quick phone snap of the Moon, and you'd rather spend £229 once than piece together a system over months.
The custom-rig optical tube
Sky-Watcher · Sky-Watcher Evostar 72ED
You've already been shooting the Milky Way with a DSLR on a tripod and you're ready to take the next step — you want a fast, colour-corrected optic that will frame huge nebulae and galaxy fields when paired with a star tracker you either own or plan to buy. You're comfortable investing in a system piece by piece, you understand that visual performance through 72mm will never rival a larger scope, and your excitement comes from seeing colour and structure emerge in stacked images, not from real-time views through an eyepiece.
Our verdict
This comparison has a catch: the Sky-Watcher Evostar 72ED is a bare optical tube. You cannot use it without a separate mount — which adds meaningful cost and complexity. The Celestron StarSense Explorer DX 102AZ is a complete, ready-to-observe package.
For most buyers, the Celestron StarSense Explorer DX 102AZ is the right choice — you can observe the same night it arrives. The Sky-Watcher Evostar 72ED makes sense if you already own a compatible mount, or are deliberately building a specific imaging setup piece by piece. If I had to choose for a first telescope: the Celestron StarSense Explorer DX 102AZ, without hesitation.
Celestron StarSense Explorer DX 102AZ
View Celestron StarSense Explorer DX 102AZ →Sky-Watcher Evostar 72ED
View Sky-Watcher Evostar 72ED →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 StarSense Explorer DX 102AZ | Sky-Watcher Evostar 72ED |
|---|---|---|
Apertureⓘ The most important spec — bigger = more light = better views | 102mm | 72mm |
Focal Length Longer = more magnification potential | 660mm | 420mm |
Focal Ratio Lower f-number = wider field of view; higher = more magnification per eyepiece | f/6.47 | f/5.83 |
Optical Design The type of optics — each design has different strengths | Refractor | Refractor |
Coatings Better coatings = more light transmission through the optics | Fully multi-coated achromatic refractor | Fully multi-coated ED doublet |
How do you point it?
| Spec | Celestron StarSense Explorer DX 102AZ | Sky-Watcher Evostar 72ED |
|---|---|---|
Mount Type The mechanical system that holds and moves the telescope | Alt-Az | None (OTA only) |
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 StarSense Explorer DX 102AZ | Sky-Watcher Evostar 72ED |
|---|---|---|
Focuser Size 2" accepts wider eyepieces and gives better low-power views | 1.25" | 2" |
Focuser Type Rack-and-pinion is standard; Crayford and dual-speed are smoother | Rack and pinion | Dual-speed Crayford (with 1.25" adapter) |
Size & weight
| Spec | Celestron StarSense Explorer DX 102AZ | Sky-Watcher Evostar 72ED |
|---|---|---|
OTA Weightⓘ Optical tube only — useful for comparing mount load capacity | 3.2kg | 1.4kg |
Total Weight Full setup including mount — this is what you lug to the car | 7.5kg | — |
Tube Length | 660mm | 390mm |
Tube Material | Aluminium | Aluminium |
What's in the box?
| Spec | Celestron StarSense Explorer DX 102AZ | Sky-Watcher Evostar 72ED |
|---|---|---|
Eyepieces Included eyepieces — more is better, but quality matters more than quantity | 25mm and 10mm Kellner | — |
Finder Scope Helps you locate areas of the sky before switching to the main eyepiece | StarSense sky recognition dock (uses your smartphone) | — |
Diagonalⓘ Tilts the eyepiece 90° for comfortable viewing — useful on refractors |
Blue highlight: Celestron StarSense Explorer DX 102AZ advantage · Amber highlight: Sky-Watcher Evostar 72ED advantage · Greyed cells: equal or subjective.