Telescope Comparison
Sky-Watcher Esprit 100ED vs Vixen ED80Sf
The price gap is real. The question is whether the extra capability is worth it at your stage.
First light
Sky-Watcher · 100mm · £1,099
The custom-rig optical tube
- 100mm refractor — optical tube only, no mount included
- 550mm focal length at f/5.5
- 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
Vixen · 80mm · £649
The custom-rig optical tube
- 80mm refractor — optical tube only, no mount included
- 600mm focal length at f/7.5
- 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
Sky-Watcher Esprit 100ED gathers 1.6× 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 ED80Sf's longer focal length reaches higher magnification with the same eyepiece — better reach for planetary detail. Sky-Watcher Esprit 100ED's shorter focal length gives a wider true field — better for large open clusters and extended nebulae.
Focal ratio
Sky-Watcher Esprit 100ED's faster f/5.5 delivers wider fields with any eyepiece — better for open clusters and large nebulae. Vixen ED80Sf's f/7.5 provides more magnification per eyepiece — better for fine planetary detail.
Mount type
Neither scope includes a mount — both require a separate purchase before you can observe.
Weight (OTA)
Vixen ED80Sf's optical tube is 2.1kg 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 | Sky-Watcher Esprit 100ED | Vixen ED80Sf |
|---|---|---|
| Planets | ||
| Moon | Excellent 100mm aperture delivers sharp crater detail and clean terminator views; the fast focal ratio means lower magnification per eyepiece but detail is still crisp | Excellent 80mm aperture with ED glass delivers sharp, colour-free crater detail; f/7.5 handles high magnification well |
| Saturn | Good Rings clearly separated, Cassini Division visible in good seeing; 550mm focal length limits image scale at the eyepiece | Good Rings clearly defined, Cassini Division visible in steady seeing; 600mm focal length adequate for useful magnification with a short Barlow |
| Jupiter | Good Two main cloud belts and GRS visible; 100mm aperture resolves belt detail but the short focal length caps useful magnification | Good Main equatorial belts and GRS visible; ED glass keeps the limb clean, but 80mm limits fine belt detail |
| Mars | Moderate Disc and polar cap visible at opposition; 100mm and 550mm focal length are limiting for surface albedo features | Challenging Small orange disc visible at opposition; polar cap hints possible but aperture too small for surface detail |
Deep sky | ||
| Orion Nebula (M42) | Excellent 100mm gathers ample light, 550mm frames the full nebula with surrounding nebulosity; f/5.5 rewards both visual and imaging use | Excellent 80mm aperture and 600mm focal length frame the full nebula with surrounding structure; trapezium resolved |
| Andromeda Galaxy (M31) | Excellent 550mm captures the full extent of M31 including companion galaxies; 100mm aperture shows outer halo hints visually | Excellent 600mm focal length captures the full extent of the galaxy; bright core and inner dust lanes visible |
| Open clusters | Excellent 550mm focal length provides generous framing — the Double Cluster, Pleiades, and similar targets are beautifully presented | Excellent 600mm focal length gives wide true field — Pleiades, Double Cluster, and M35 all fit beautifully with pinpoint stars |
| Globular clusters | Moderate M13 and M5 appear granular with hints of edge resolution; core remains unresolved at 100mm | Moderate M13 and M3 appear as fuzzy concentrated balls; 80mm cannot resolve individual stars |
| Faint galaxies | Moderate 100mm shows brighter Messier galaxies as fuzzy patches; NGC targets require dark skies and are at the limit visually | Moderate Brighter Messier galaxies (M81/M82, M51) visible as faint smudges; no structure detail at 80mm |
| Milky Way / wide field | Good 550mm is slightly long for sweeping Milky Way panoramas but still delivers rich star fields; excellent for targeted regions like Cygnus | Good 600mm is slightly long for sweeping Milky Way fields but still delivers rich star clouds with a wide-field eyepiece |
Other | ||
| Double stars | Good 100mm resolves down to about 1.2 arcsec; chromatic correction is excellent but the fast focal ratio makes splitting tight pairs trickier than in a long-focus refractor | Good Clean ED optics split Albireo easily and handle tighter pairs like Castor; Dawes limit ~1.45 arcsec |
| Astrophotography (deep sky) | Not recommended No mount included — on a suitable equatorial GoTo mount this scope would rate Excellent (f/5.5, 100mm, flat field to full-frame), but as sold it cannot track | Not applicable |
| Astrophotography (planetary) | Moderate 100mm aperture is workable with a Barlow and planetary camera, but 550mm native focal length requires significant amplification; needs a tracking mount | Not applicable |
| Emission nebulae (imaging) | Excellent Fast f/5.5 ratio and 550mm focal length are ideal for large emission targets like the Veil, Rosette, and Heart Nebulae on APS-C or full-frame sensors | Not applicable |
| Galaxy groups (imaging) | Good 550mm frames targets like the Leo Triplet and Markarian's Chain well on APS-C; 100mm gathers enough light for reasonable exposure times | Not applicable |
The real tradeoff
Both scopes are capable. The question is which one fits the way you actually observe.
Sky-Watcher Esprit 100ED
- You'll mount up, plug in your camera, and spend most of your session framing deep-sky targets — the integrated field flattener means you're not fiddling with extra corrector spacing, you're just nailing 55mm back-focus and shooting, and the f/5.5 speed means shorter sub-exposures for a given signal level compared to the Vixen's f/7.5.
- You'll see the difference on your screen the next morning: pinpoint stars across a full-frame sensor, the entire Veil Nebula complex in a single frame, and enough focal length at 550mm to still resolve the Leo Triplet into three distinct galaxies — this scope rewards you for investing in a solid mount and guiding setup.
- You'll occasionally drop an eyepiece in and enjoy clean views of the Moon, split the Trapezium, and resolve M13 into a granular ball — but you'll always sense you're borrowing visual time from an instrument that was built to sit behind a camera, not behind your eye.
Vixen ED80Sf
- You'll grab this tube, toss it on whatever mount you have, and be observing in minutes — at under 2.5kg it's genuinely portable in a way the Esprit never will be, and you'll find yourself using it on weeknights precisely because setup is trivial.
- You'll spend your evenings sweeping open clusters and tracing nebula outlines at the eyepiece, appreciating the colour-clean ED views on the lunar terminator and Saturn's rings — the f/7.5 focal ratio gives you a more forgiving, slower cone of light that's comfortable for visual use at moderate magnifications.
- You'll dip into astrophotography and get surprisingly pleasing results on APS-C with a field flattener, but you'll notice the 80mm aperture running out of steam on faint targets sooner than you'd like — longer exposures and more total integration time are the tax you pay for portability.
The dark side
Every scope has a personality. Here’s where each one gets difficult.
Sky-Watcher
Sky-Watcher Esprit 100ED
The OTA is £1099 before you buy a single accessory — once you add an equatorial mount capable of handling 6–7kg of imaging payload, a guidescope, and a camera, you're realistically looking at £2500–£3000+ for a working system.
The integrated field flattener demands exactly 55mm of back-focus spacing; get it wrong and your corner stars stretch into seagulls, so you'll need spacer rings and careful measurement before your first imaging session.
Some narrowband filters produce halos or uneven illumination across full-frame sensors at f/5.5 — if you're shooting Ha or OIII on a full-frame camera, test your filter compatibility before committing to a workflow.
Vixen
Vixen ED80Sf
The standard model ships with a 1.25"-only focuser, which locks you out of 2" wide-field eyepieces and limits your accessory upgrade path compared to the Esprit's 2" focuser.
At 80mm aperture you're paying premium ED-glass pricing — £649 — for light-gathering power that won't resolve globular clusters or reveal faint galaxy structure the way even a modest 100mm scope can.
Without a dedicated field flattener, camera sensor edges show coma and field curvature at f/7.5 — so astrophotography still demands an additional corrector purchase on top of the OTA, mount, and camera costs.
Which is right for you?
Two different buyers. Two different right answers.
The custom-rig optical tube
Sky-Watcher · Sky-Watcher Esprit 100ED
You already own a solid equatorial mount — or you're ready to buy one — and your primary goal is deep-sky astrophotography. You've outgrown an 80mm refractor and want flat, pinpoint stars across a large sensor without bolting on external correctors. You're comfortable spending £2500+ on a complete imaging rig and you understand that back-focus spacing, guiding, and post-processing are all part of the hobby. You might put an eyepiece in occasionally, but you judge a session's success by what your stacking software produces, not what your eye saw at the focuser.
The custom-rig optical tube
Vixen · Vixen ED80Sf
You want a single, lightweight tube that you'll actually take outside on a clear weeknight — something that delivers clean, colour-free views of the Moon, planets, and bright deep-sky objects, and that can double as an entry-level imaging platform when you're ready to experiment. You value build precision and portability over raw aperture, and you're willing to accept that 80mm will never punch as deep as 100mm. You're not yet committed to a full imaging workflow, and you'd rather spend less on the OTA now while you figure out whether astrophotography or visual observing is your long-term path.
Our verdict
At £649 versus £1,099, the Sky-Watcher Esprit 100ED costs 69% more. It delivers 20mm more aperture — a real and visible advantage on faint targets.
If budget is a genuine constraint, the Vixen ED80Sf will make you a happy observer. The Sky-Watcher Esprit 100ED'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 Vixen ED80Sf, use it for a year, then upgrade knowing exactly what you want.
Sky-Watcher Esprit 100ED
View Sky-Watcher Esprit 100ED →Vixen ED80Sf
View Vixen ED80Sf →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 Esprit 100ED | Vixen ED80Sf |
|---|---|---|
Apertureⓘ The most important spec — bigger = more light = better views | 100mm | 80mm |
Focal Length Longer = more magnification potential | 550mm | 600mm |
Focal Ratio Lower f-number = wider field of view; higher = more magnification per eyepiece | f/5.5 | f/7.5 |
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 triplet with FMC on all air-to-glass surfaces | Fully multi-coated ED doublet on all air-to-glass surfaces |
How do you point it?
| Spec | Sky-Watcher Esprit 100ED | Vixen ED80Sf |
|---|---|---|
Mount Type The mechanical system that holds and moves the telescope | None (OTA only) | 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 Esprit 100ED | Vixen ED80Sf |
|---|---|---|
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 | Dual-speed Crayford (10:1 reduction, with 1.25" adapter) | Dual-speed Crayford (with 1.25" adapter) |
Size & weight
| Spec | Sky-Watcher Esprit 100ED | Vixen ED80Sf |
|---|---|---|
OTA Weightⓘ Optical tube only — useful for comparing mount load capacity | 3.9kg | 1.8kg |
Tube Length | 535mm | 528mm |
Tube Material | Aluminium, white powder coat | Aluminium |
What's in the box?
| Spec | Sky-Watcher Esprit 100ED | Vixen ED80Sf |
|---|---|---|
Diagonal Tilts the eyepiece 90° for comfortable viewing — useful on refractors |
Blue highlight: Sky-Watcher Esprit 100ED advantage · Amber highlight: Vixen ED80Sf advantage · Greyed cells: equal or subjective.