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Sky-Watcher Equinox 80ED Review

Sky-Watcher’s Evostar 80 ED DS Pro is a pretty common telescope these days. Its combination of modest price, easy mounting and usefully wide field make an ideal starter’s imaging scope. But Sky-Watcher make another 80ED – the Equinox 80ED – that is a completely different telescope and seems much less common.

Here I take a look at the differences between the ED DS Pro and the Equinox at this size and compare the Equinox 80ED to a premium scope of similar aperture and focal length, the Tele Vue TV-76.

 

At A Glance

Telescope

Sky-Watcher Equinox 80ED

Aperture

80mm

Focal Length

500mm

Focal Ratio

F6.2

Length

~370mm

Weight

2.9 Kg

 Data from Me/SW.

 

What’s in the Box?

Like others in Sky-Watcher’s premium Equinox range, all you get is an OTA and case – unlike the better spec’d ED Pro.

 

Design and Build

The 80ED is available in two ranges, the ED DS Pro and the Equinox.

The ED DS Pro is the cheaper of the two, with a fixed dew-shield and a rolled tube in their familiar ‘black diamond’ (i.e. white and metallic black) colours with a white cast focuser. The other Sky-Watcher 80ED, the Equinox on review here, is different. For one thing, it comes in a shiny black all-CNC tube with a sliding dewshield and CNC focuser. But unlike the larger (100ED and 120ED) Equinox models, the optical spec’ is different too.

Optics

The most important thing to understand is that Equinox 80ED is F6.3 (500mm focal length), whilst the cheaper ED Pro is F7.5 (600mm focal length). Why? No idea. Does this matter? Well, on one hand, the ED DS Pro’s extra 1+ F-stops significantly increases exposure times for deep sky imaging. Whilst on the other, the slower lens has the potential to show less aberrations, both chromatic (false colour) and monochromatic (like astigmatism, coma and field curvature that distort star images in the outer parts of the field).

Otherwise, the lenses are both ED doublets that are Chinese made, but use glasses from premium Japanese/European brands. Sky-Watcher have strongly marketed their use of Ohara’s FPL53 for the positive crown element and a high-grade flint from Schott for the negative. FPL53 is one of the best high-fluoride ED glasses around and is used in many of the best apochromatic lenses.

The lens appears well coated (perhaps better than the typical ‘China green’ used on the ED Pro) and sits in a slim, non-adjustable cell.

Tube

The Equinox sports lots of piano-black, too many chrome parts and is a bit too shiny generally. However, the Equinox is beautifully built, whatever you think of the shiny finish. What looks like chrome is chrome, i.e. metal and not plastic (though I’ve heard it can flakes off). The tube looks plastic, but it isn’t - it’s beautifully anodised metal too, which is why the Equinox is heavy. In fact, the external build quality of the Equinox is almost too good, too slick and polished; it looks a bit cheap and flashy, a bit flat-screen TV, especially compared with something like a Tele Vue 76.

The other disadvantage of that CNC tube is that it’s fairly heavy for a scope of this size – about 2.6 Kg. For comparison, the Equinox is a lot heavier than either the Borg 90FL or Takahashi FC-76DC.

Look past the 80ED lens and you find concentric ridge baffles finished in matte black and a generally high level of internal quality as well.

Focuser

The Equinox focuser is a standard premium Chinese Crayford with a dual speed knob on the right. Mostly it’s anodised CNC-machined metal like the tube and is very precise and smooth in operation.  I can detect no play in the drawtube, even at full stretch, which is great news for imagers. Not only is it smooth, but the focuser has lots of travel, with a scale for imagers. The focuser remains smooth even with heavy eyepieces.

The Equinox throws in a final feature anyone using refractors on equatorial mounts will appreciate: a rotator for the focuser. The knurled chrome ring in front of the focuser twists to free the whole focuser for rotation. It’s intended as a camera rotator – allowing perfect framing for imaging - but I love rotators for visual use too: you can adjust eyepiece position without risking dumping an expensive diagonal and eyepiece on the floor. The Equinox rotator is a bit stiff, but is still a useful feature.

Mounting

The larger Equinox models come with tube rings, but the 80ED (and the 66ED too) have a small Vixen (eq5) compatible dovetail plate attached directly to the tube. This is a less flexible solution than rings, but at least there is a standard ¼-20 thread on the bottom for a camera tripod.

The Equinox 80ED is a bit heavier than the ED Pro, but it still mounts on just about anything, photo tripod and head included (as shown here). You could certainly start off with an EQ5 for imaging, especially since the short focal length will be less fussy about tracking errors.

Sky-Watcher’s Equinox 80ED (right) on a photo tripod, next to Tele Vue’s TV-76.

Equinox 80ED comes with a high-quality hard case, but no other accessories as standard (the diagonal shown is not in the package price).

Accessories

The Equinox lacks the diagonal, eyepiece and finder you get with the ED Pro, but the case is finer quality and lined with proper foam not packaging style ethafoam, like the ED Pro’s.

 

In Use – Daytime

Daytime views are sharp, but high-contrast subjects do show some false colour, as you can see from the photo of one of my local Jackdaws below. False colour is a little worse than a Tele Vue TV-76 and probably slightly worse than the slower ED Pro model too.

As this image shows, daytime views and photos through the Equinox 80ED are sharp but reveal some false colour.

Deep sky images show some field curvature at the edges, but good coverage. Brighter O-A stars reveal some bloat.

Cropped image of the Moon in twilight through Equinox 80ED shows good detail.

 

In Use – Astrophotography

The 80ED produces wide, sharp deep sky images. Bloating on bright O-A (blue-white) stars is typically a bit worse than the image above suggests, in which none of the stars are really bright. Field curvature on APS-C isn’t too bad, but a keen imager will want to get a good flattener or reducer.

Images of the Moon are small due to the short focal length (and thus image scale), but sharp and detailed nonetheless (see above).

 

In Use – The Night Sky

General Observing Notes

The Equinox is a refined scope to use. The focuser is smooth, largely free of image shift and accurate with its fine-focus knob. The long retractable dewshield protects the objective well. The view is generally good, though perhaps not quite as good as the (much more expensive) Tele Vue TV-76 I was testing alongside.

Cool Down

Cool down for a small doublet like this is fast, ideal for quick looks between showers.

Star Test

The star test looked pretty good, with nice diffraction rings either side of focus.

The Moon

The Moon showed good detail and took higher powers quite well, but I noticed more stray light bleeding into the black space around the Lunar limb than I did with the TV-76 and I thought contrast was slightly poorer too.

Mars

Turning to Mars just after opposition, with a disk size of about 14 arcsecs, views were much the same through the 80ED and TV-76, though the altaz mounts we were using were awkward at the high powers needed to resolve detail. Nonetheless, Syrtis Major was clearly seen in both scopes at 120x, a magnificationwhich still yielded a sharp image with the Equinox 80. I couldn’t see much difference between the two scopes on Mars, but thought high-power focus was a little snappier in the Tele Vue.

Deep Sky

If the Moon through the Equinox seemed a bit soft compared to the near-perfect view through the TV-76, the same couldn’t have been said of the deep sky objects we viewed earlier, before Moonrise. Both scopes gave a commendably flat sharp field, with excellent definition on the Orion Nebula and pinpoint stars in the Trapezium. Contrast on the nebulosity was much the same in both scopes, but I thought stars were a bit tighter and more diamond-like in the TV-76, though the difference was tiny. My mate observed that the view through the ED80 seemed wider and I agreed. When we checked, the FOV was much the same, as expected, but the fainter stars in the ED80 were brighter due to its larger aperture (80mm vs 76mm = 10% more light gathering).

M31 was similar in both scopes and looks great at this focal length which gets much of the galaxy in the field in a way bigger scopes just can’t. Short focal length refractors like this excel on star fields and open clusters, like those running up through Auriga (see image of M36 below).

 

Summary

If you want a low-ish cost wide-field astrograph, then the Equinox 80 is an excellent choice: with its fast lens and accurate dual-speed focuser it might make a better imaging scope than the Evostar ED DS Pro version. Interestingly, these days discounted prices for the Equinox are close to the DS Pro model.

You would need a flattener or reducer for serious or full-frame imaging, but this focal length leaves you spoiled for choice when it comes to reducers, with options from Tele Vue through William Optics and Borg too.

The Sky-Watcher Equinox ED is not bad as a grab-n-go or travel scope either, though a bit larger and heavier than the TV-76 that I was testing alongside. It will mount on most small mounts for visual use, including photo tripods.

Performance for both visual and imaging aren’t quite up to the premium standards of Tele Vue, Takahashi and Borg - with slightly less glitteringly pinpoint stars and more scattered light on bright objects like the Moon - but then neither is the price.

The Sky-Watcher Equinox 80ED is recommended as a grab-n-go visual scope or budget astrograph.

Updated by Roger Vine 2018

 

Sky-Watcher’s Equinox 80ED alongside Tele Vue TV-76.

 

 

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