Telescope Comparison
Askar 80PHQ vs Sky-Watcher Evostar 100ED
The price gap is real. The question is whether the extra capability is worth it at your stage.
First light
Askar · 80mm · £799
The custom-rig optical tube
- 80mm refractor — optical tube only, no mount included
- 448mm focal length at f/5.6
- 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
Sky-Watcher · 100mm · £449
The custom-rig optical tube
- 100mm refractor — optical tube only, no mount included
- 900mm focal length at f/9
- 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 Evostar 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
Sky-Watcher Evostar 100ED's longer focal length reaches higher magnification with the same eyepiece — better reach for planetary detail. Askar 80PHQ's shorter focal length gives a wider true field — better for large open clusters and extended nebulae.
Focal ratio
Askar 80PHQ's faster f/5.6 delivers wider fields with any eyepiece — better for open clusters and large nebulae. Sky-Watcher Evostar 100ED's f/9 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)
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 | Askar 80PHQ | Sky-Watcher Evostar 100ED |
|---|---|---|
| Planets | ||
| Moon | Excellent 80mm aperture delivers sharp lunar detail; short focal length limits magnification but crater fields and terminator are crisp | Excellent 100mm aperture and f/9 focal ratio reward high magnification with sharp, high-contrast lunar detail |
| Saturn | Good Rings clearly visible at modest magnification; 448mm focal length limits high-power planetary detail | Good 900mm focal length and clean ED optics show rings, Cassini Division in good seeing, and subtle disc banding |
| Jupiter | Good Main cloud belts and Galilean moons visible, but the short focal length constrains useful magnification | Good 100mm resolves two or more cloud belts, GRS, and moon shadow transits; f/9 handles high power well |
| Mars | Challenging Small disc visible at opposition; 80mm aperture and 448mm focal length insufficient to resolve surface features reliably | Moderate Disc visible with polar cap and large albedo features at opposition, but 100mm limits fine surface detail |
Deep sky | ||
| Orion Nebula (M42) | Excellent Bright target framed beautifully by the wide field; f/5.6 speed and sub-600mm focal length show full nebula extent | Good Bright nebula core and trapezium well shown, but 900mm focal length crops the outer wings |
| Andromeda Galaxy (M31) | Excellent 448mm focal length captures the full extent of M31 including outer halo; 80mm aperture adequate for the bright core and dust lanes | Good Bright core and inner halo visible; 900mm frames only the central region, missing the full extent |
| Open clusters | Excellent Wide field at 448mm frames large clusters like the Double Cluster, Pleiades, and Hyades superbly | Good Compact clusters like M35 frame well; larger groups like the Double Cluster fill the low-power field |
| Globular clusters | Moderate 80mm aperture shows bright globulars like M13 as granular but unresolved fuzzy patches | Moderate M13 and M5 appear granular at high power but the core remains unresolved at 100mm |
| Faint galaxies | Moderate 80mm aperture detects brighter Messier galaxies as smudges; insufficient light grasp for dim NGC targets visually | Moderate Brighter Messier galaxies detectable as smudges; 100mm lacks the aperture for structure or faint targets |
| Milky Way / wide field | Excellent 448mm focal length at f/5.6 — ideal for sweeping rich star fields and Milky Way structure | Not recommended 900mm focal length produces too narrow a field for sweeping Milky Way star fields |
Other | ||
| Double stars | Good 80mm resolves wider doubles cleanly; the fast f/5.6 focal ratio is less ideal than a long-FL refractor for tight pairs | Excellent Clean ED optics at f/9 produce tight diffraction patterns; Dawes limit around 1.2 arcseconds |
| Astrophotography (deep sky) | Not recommended OTA only with no mount — requires a separate equatorial or GoTo mount for any deep-sky imaging; on a suitable mount this would rate Excellent | Not applicable |
| Astrophotography (planetary) | Challenging 80mm aperture and 448mm focal length undersized for planetary imaging; a Barlow helps but cannot overcome the aperture limit | Not applicable |
| Wide-field emission nebulae (imaging) | Excellent Fast f/5.6 quad APO with integrated flattener is purpose-built for targets like the Veil, North America, and Rosette Nebulae on a suitable mount | Not applicable |
The real tradeoff
Both scopes are capable. The question is which one fits the way you actually observe.
Askar 80PHQ
- You'll spend your evenings framing enormous nebula complexes — the Veil, the Heart and Soul side by side — and watching sub-exposures stack into deeply detailed wide-field portraits, because the f/5.6 speed and integrated field flattener mean you're collecting usable data from the moment guiding locks on.
- You'll never fiddle with a separate field flattener or agonise over corrector spacing on a new camera — but you will need to nail the 55mm back-focus distance precisely, and if you get it wrong, you'll see stretched stars in the corners that no amount of post-processing can fix.
- You'll appreciate how light and compact the tube is when you're loading the car for a dark-sky trip, but when you do stick an eyepiece in for a quick visual peek, you'll be reminded that 80mm of aperture at 448mm focal length delivers pleasant wide-field sweeps and not much else — planets will look like featureless dots.
Sky-Watcher Evostar 100ED
- You'll spend your sessions chasing fine detail — tracing Hadley Rille at 200×, splitting Epsilon Lyrae, watching the Cassini Division sharpen as the seeing steadies — and the clean, low-fringing views from the ED doublet at f/9 will keep you at the eyepiece longer than you planned.
- You'll find the 100mm aperture hits a genuine sweet spot for high-contrast planetary and lunar work in a refractor, showing you real surface detail on Jupiter and Saturn rather than just coloured blobs, but you'll also notice you run out of light grasp on faint deep-sky targets sooner than friends with 8-inch reflectors.
- You can bolt a camera on and get sharp, well-corrected star fields, but you'll be stacking significantly longer total integration times at f/9 to match what a fast astrograph captures — and if you want wide-field Milky Way mosaics, you'll be shooting many more panels than someone with a 448mm focal length.
The dark side
Every scope has a personality. Here’s where each one gets difficult.
Askar
Askar 80PHQ
The £799 price buys only the tube — you'll still need a mount, guide scope, guide camera, and imaging camera, so your actual system cost can easily triple or quadruple the OTA price before you capture a single frame.
The 80mm aperture is the smallest in the serious astrograph class; compared to 100–130mm APO refractors, you're collecting less light per sub-exposure and will need longer total integration times to reach the same signal-to-noise on faint targets.
Some users report the stock focuser can flex or slip under heavy camera payloads, and getting the back-focus spacing wrong by even a millimetre or two introduces noticeable field curvature and corner star elongation that undermines the whole point of the integrated quadruplet design.
Sky-Watcher
Sky-Watcher Evostar 100ED
At £449 the OTA is a bargain, but it ships with no mount, no diagonal, no finder, and no eyepieces — budget at least another £300–500 for visual accessories and a usable mount, far more if you want imaging-capable tracking.
As an ED doublet rather than a triplet, there is residual chromatic aberration visible on the brightest stars and the lunar limb — noticeably better than an achromat, but not as surgically clean as a triplet or quadruplet APO at this aperture.
The 4.4 kg tube plus accessories demands at least a mid-range equatorial mount for stable imaging, and the 900mm f/9 focal length means long exposures and high sensitivity to tracking errors — this is not a grab-and-shoot imaging setup.
Which is right for you?
Two different buyers. Two different right answers.
The custom-rig optical tube
Askar · Askar 80PHQ
You already own a solid equatorial mount and a cooled astro camera, and what you want is a compact, fast astrograph that delivers flat, pinpoint stars across a full-frame sensor without the hassle of spacing a separate field flattener. You're drawn to big, sweeping deep-sky targets — wide nebula complexes, galaxy groups, Milky Way star fields — and you value short exposure times over visual use. You're comfortable with back-focus calculations and imaging workflows, and you accept that 80mm of aperture means you're trading raw light grasp for portability and optical speed. This is not for you if you want to look through an eyepiece with any regularity, if you need a complete ready-to-use system, or if your primary targets are planets.
The custom-rig optical tube
Sky-Watcher · Sky-Watcher Evostar 100ED
You love the Moon, planets, and double stars, and you want a refractor that delivers genuinely crisp, low-fringing views at high magnification without breaking the bank. You're building your own system around a mount you already own or plan to choose yourself, and you appreciate that the Evostar 100ED can pull double duty as an occasional imaging OTA when you're ready to try astrophotography — even if it won't match a dedicated astrograph's speed. You value the extra 20mm of aperture over the 80PHQ for visual light grasp and resolving power. This is not for you if your primary goal is fast wide-field deep-sky imaging, if you need a complete out-of-the-box package, or if you want to capture sprawling nebula mosaics without spending all night on integration time.
Our verdict
At £449 versus £799, the Askar 80PHQ costs 78% more. The extra money buys a more capable mount and better build quality, not larger optics.
For most buyers starting out, the Sky-Watcher Evostar 100ED is the sensible choice — put the savings into a better eyepiece. The Askar 80PHQ makes sense once you know exactly why you need what it offers. If I had to choose: the Sky-Watcher Evostar 100ED, and spend the difference on a quality eyepiece.
Askar 80PHQ
View Askar 80PHQ →Sky-Watcher Evostar 100ED
View Sky-Watcher Evostar 100ED →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 | Askar 80PHQ | Sky-Watcher Evostar 100ED |
|---|---|---|
Apertureⓘ The most important spec — bigger = more light = better views | 80mm | 100mm |
Focal Length Longer = more magnification potential | 448mm | 900mm |
Focal Ratio Lower f-number = wider field of view; higher = more magnification per eyepiece | f/5.6 | f/9 |
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 PHQ quadruplet on all surfaces | Fully multi-coated ED doublet |
How do you point it?
| Spec | Askar 80PHQ | Sky-Watcher Evostar 100ED |
|---|---|---|
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 | Askar 80PHQ | Sky-Watcher Evostar 100ED |
|---|---|---|
Focuser Size 2" accepts wider eyepieces and gives better low-power views | 2" / 1.25" | 2" |
Focuser Type Rack-and-pinion is standard; Crayford and dual-speed are smoother | Dual-speed Crayford 2" (with 1.25" adapter) | Dual-speed Crayford (with 1.25" adapter) |
Size & weight
| Spec | Askar 80PHQ | Sky-Watcher Evostar 100ED |
|---|---|---|
OTA Weightⓘ Optical tube only — useful for comparing mount load capacity | 2.8kg | 2.6kg |
Tube Length | 360mm | 720mm |
Tube Material | Aluminium | Aluminium |
What's in the box?
| Spec | Askar 80PHQ | Sky-Watcher Evostar 100ED |
|---|---|---|
Diagonal Tilts the eyepiece 90° for comfortable viewing — useful on refractors |
Blue highlight: Askar 80PHQ advantage · Amber highlight: Sky-Watcher Evostar 100ED advantage · Greyed cells: equal or subjective.