Telescope Comparison
Sky-Watcher Evostar 80ED + HEQ5 Pro vs Vixen SD81S
The Sky-Watcher Evostar 80ED + HEQ5 Pro is a complete setup. The Vixen SD81S needs a mount before it's usable.
First light
Sky-Watcher · 80mm · £690
The automated deep-sky platform
- 80mm refractor 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
- 22.5kg total — requires a fixed garden spot or car transport
Vixen · 81mm · £1,199
The custom-rig optical tube
- 81mm refractor — optical tube only, no mount included
- 625mm focal length at f/7.72
- 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
Vixen SD81S gathers 1× 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
Vixen SD81S's longer focal length reaches higher magnification with the same eyepiece — better reach for planetary detail. Sky-Watcher Evostar 80ED + HEQ5 Pro's shorter focal length gives a wider true field — better for large open clusters and extended nebulae.
Focal ratio
Sky-Watcher Evostar 80ED + HEQ5 Pro's faster f/7.5 delivers wider fields with any eyepiece — better for open clusters and large nebulae. Vixen SD81S's f/7.72 provides more magnification per eyepiece — better for fine planetary detail.
Mount type
Vixen SD81S has no mount — add a compatible mount before you can observe. Sky-Watcher Evostar 80ED + HEQ5 Pro is a complete ready-to-use system.
Weight (OTA)
Similar optical tube weight. Any portability difference between these setups comes from the mount, not the tube itself.
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 | Sky-Watcher Evostar 80ED + HEQ5 Pro | Vixen SD81S |
|---|---|---|
| Planets | ||
| Moon | Good 80mm aperture delivers sharp, colour-free craters and terminator detail; f/7.5 limits extreme magnification compared to longer focal length scopes | Excellent 81mm aperture with superb colour correction delivers crisp, fringe-free lunar detail; f/7.7 supports rewarding high-magnification views |
| Saturn | Moderate Rings clearly visible and disc shows colour, but 600mm focal length keeps the image small — Cassini Division requires excellent seeing and high-power eyepieces | Good Rings clearly defined, Cassini Division visible in good seeing; 625mm focal length limits image scale but clean optics compensate |
| Jupiter | Moderate Main equatorial belts visible; 80mm aperture and 600mm focal length limit detail on the Great Red Spot and festoons | Good Main equatorial belts and GRS visible with high contrast and no false colour; aperture limits finer belt detail |
| Mars | Challenging Small orange disc visible at opposition; polar cap glimpsable in ideal conditions but surface albedo features are beyond this aperture | Challenging Small disc visible at opposition with possible polar cap hint, but 81mm aperture cannot resolve surface albedo features |
Deep sky | ||
| Orion Nebula (M42) | Excellent Wide 600mm field frames the full nebula and Running Man beautifully — bright enough to show structure visually and a superb imaging target | Excellent 625mm focal length frames the nebula well; 81mm gathers enough light to show core structure and nebulosity wings |
| Andromeda Galaxy (M31) | Excellent 600mm focal length captures the full galaxy extent including companion galaxies; one of this scope's signature imaging targets | Excellent 625mm focal length captures the galaxy's full extent; core and dust lanes visible, though outer halo is faint at 81mm |
| Open clusters | Excellent Wide field perfectly frames the Double Cluster, Pleiades, and other large clusters with pin-sharp stars across the field | Excellent Wide true field at 625mm beautifully frames clusters like the Pleiades and Double Cluster with pinpoint stars |
| Globular clusters | Challenging 80mm aperture cannot resolve individual stars — M13 and M3 appear as fuzzy, unresolved glows | Challenging 81mm cannot resolve individual stars — globulars appear as fuzzy, concentrated glows |
| Faint galaxies | Moderate Visually limited by 80mm aperture; however, with camera and stacked exposures, many faint galaxies are accessible photographically | Moderate Brighter Messier galaxies visible as diffuse patches; 81mm lacks the light grasp for structure or fainter NGC targets |
| Milky Way / wide field | Good 600mm focal length is at the long end for sweeping Milky Way fields visually, but on camera the wide field and fast optics capture rich starfields well | Good 625mm focal length is moderately wide; rich starfields are enjoyable but the scope is too narrow for grand sweeping views |
Other | ||
| Double stars | Good Clean ED optics split well-separated doubles cleanly; Dawes limit at 80mm is ~1.45 arcsec, so tight pairs are out of reach | Good Clean optics and near-zero chromatic aberration make this a satisfying double star scope; Dawes limit around 1.4 arcseconds |
| Astrophotography (deep sky) | Excellent HEQ5 Pro GoTo mount with tracking, 80mm ED optics at f/7.5 (f/6.3 with reducer), and massive payload headroom make this a benchmark widefield imaging rig | Not recommended No mount or tracking included; when paired with a suitable equatorial mount this would rate Excellent (81mm, f/7.7, superb correction) |
| Astrophotography (planetary) | Challenging 80mm aperture and 600mm focal length produce a small planetary disc — limited detail even with lucky imaging techniques | Moderate Clean optics suit planetary capture, but 81mm aperture and 625mm focal length limit resolution and image scale |
The real tradeoff
Both scopes are capable. The question is which one fits the way you actually observe.
Sky-Watcher Evostar 80ED + HEQ5 Pro
- You'll spend the first ten minutes of every session on polar alignment, but once locked in, the HEQ5 Pro's computerized tracking will hold your target steady for 3–5 minute exposures without a guide camera.
- You get a complete imaging system out of the box — mount, head, tripod, and computerized GoTo — so your first night is spent imaging, not assembling.
- Your observing sessions reward patience with wide nebulae: you'll frame the full Orion region, the Heart Nebula, or the North America Nebula in a single shot, and stack them into publishable results.
Vixen SD81S
- You'll choose your own mount, which means months of research, compatibility checking, and careful budgeting — but you'll own a system tailored exactly to your needs and budget.
- You can grab the OTA alone and hike to a dark site, slap it on an alt-azimuth mount for a night of pure visual observing, then take the same optical tube to an equatorial rig the next weekend for imaging.
- Your observing sessions reward optical perfectionism: Saturn's Cassini Division splits cleanly, lunar craters show knife-edge definition, and you'll see colour-free star images that make lesser ED scopes look purple by comparison.
The dark side
Every scope has a personality. Here’s where each one gets difficult.
Sky-Watcher
Sky-Watcher Evostar 80ED + HEQ5 Pro
80mm aperture means faint galaxies and globular clusters remain dim smudges; planetary detail is modest and high magnification work shows the limits of modest aperture.
The ED doublet exhibits slight residual chromatic aberration on bright stars at high magnification, and without the separate field flattener (not included), edge stars will show coma on camera sensors.
The HEQ5 Pro mount head weighs ~10 kg and requires careful polar alignment every session — this is not a grab-and-go setup, and the full rig demands a sturdy tripod and patience to balance.
Serious astrophotography requires additional investment in astronomy camera, guidescope, autoguiding software, image stacking software, and filters — the bundle price is only the beginning.
Vixen
Vixen SD81S
Sold as OTA only: no mount, finder, diagonal, or eyepiece included, so total system cost will exceed £2000 when you add even a modest equatorial mount.
81mm aperture is a hard ceiling for resolving fine planetary detail or faint deep-sky objects; it is not meaningfully more capable than the 80mm Evostar for visual deep-sky work.
Vixen's proprietary dovetail and accessory ecosystem may require adapters to work with third-party mounts, guide scopes, or camera rotators, adding cost and compatibility headaches.
The SD flattener/reducer essential for serious imaging costs £250–£350 additional and is not included; even as an SD-optimized scope, field curvature without it will degrade edge stars on camera sensors.
Which is right for you?
Two different buyers. Two different right answers.
The automated deep-sky platform
Sky-Watcher · Sky-Watcher Evostar 80ED + HEQ5 Pro
You're an intermediate observer ready to commit to astrophotography but want a complete, proven, mount-included system that removes the barrier to your first guided exposure; you'll image wide nebulae and galaxies, tolerate modest visual performance, and value the HEQ5 Pro's reliability and massive payload headroom for future upgrades.
The custom-rig optical tube
Vixen · Vixen SD81S
You're a visual observer or experienced imager who knows exactly which mount you want, refuses compromise on optical purity, and will spend £300–400 more for a system tailored to your needs; you value grab-and-go portability, clean high-magnification lunar and planetary views, and the freedom to pair this OTA with any mount on the market.
Our verdict
This comparison has a catch: the Vixen SD81S is a bare optical tube. You cannot use it without a separate mount — which adds meaningful cost and complexity. The Sky-Watcher Evostar 80ED + HEQ5 Pro is a complete, ready-to-observe package.
For most buyers, the Sky-Watcher Evostar 80ED + HEQ5 Pro is the right choice — you can observe the same night it arrives. The Vixen SD81S 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 Sky-Watcher Evostar 80ED + HEQ5 Pro, without hesitation.
Sky-Watcher Evostar 80ED + HEQ5 Pro
View Sky-Watcher Evostar 80ED + HEQ5 Pro →Vixen SD81S
View Vixen SD81S →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 | Sky-Watcher Evostar 80ED + HEQ5 Pro | Vixen SD81S |
|---|---|---|
Apertureⓘ The most important spec — bigger = more light = better views | 80mm | 81mm |
Focal Length Longer = more magnification potential | 600mm | 625mm |
Focal Ratio Lower f-number = wider field of view; higher = more magnification per eyepiece | f/7.5 | f/7.72 |
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 ED glass, FMC on all air-to-glass surfaces | Fully multi-coated SD (Super Duplex) glass doublet |
How do you point it?
| Spec | Sky-Watcher Evostar 80ED + HEQ5 Pro | Vixen SD81S |
|---|---|---|
Mount Type The mechanical system that holds and moves the telescope | GoTo (Computerised) | 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 | Sky-Watcher Evostar 80ED + HEQ5 Pro | Vixen SD81S |
|---|---|---|
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 | Crayford dual-speed (with 1.25" adapter) | Dual-speed Crayford (with 1.25" adapter) |
Size & weight
| Spec | Sky-Watcher Evostar 80ED + HEQ5 Pro | Vixen SD81S |
|---|---|---|
OTA Weightⓘ Optical tube only — useful for comparing mount load capacity | 2.2kg | 2kg |
Total Weight Full setup including mount — this is what you lug to the car | 22.5kg | — |
Tube Length | 600mm | 540mm |
Tube Material | Aluminium, white powder coat | Aluminium |
What's in the box?
| Spec | Sky-Watcher Evostar 80ED + HEQ5 Pro | Vixen SD81S |
|---|---|---|
Eyepieces Included eyepieces — more is better, but quality matters more than quantity | 25mm Super eyepiece | — |
Finder Scope Helps you locate areas of the sky before switching to the main eyepiece | 8x50 right-angle correct-image finder with illuminated reticle | — |
Diagonal Tilts the eyepiece 90° for comfortable viewing — useful on refractors |
Blue highlight: Sky-Watcher Evostar 80ED + HEQ5 Pro advantage · Amber highlight: Vixen SD81S advantage · Greyed cells: equal or subjective.