Tele Vue 76 versus SkyWatcher Equinox 80 ED

It’s getting hard to recall that back a few years APO refractors were only really available from a few “boutique” manufacturers: think Takahashi, Astro-Physics and TeleVue. Then along came a telescope that looked much like the previous efforts from the Chinese, but with a proper apochromatic lens, (instead of a low-power-visual-only fast achromat): welcome the ED80.

The original ED80 caused quite a stir, even if it still had the tube and mechanicals from the previous era and was bigger and had a longer focal length than many wanted. Now, barely five years on, the world of small APOs has changed completely. Most small refractors are now Chinese made; TeleVue has quietly dropped its line of semi-apos and appears to be concentrating on high-end Petzvals; Astro-physics have said they will never make another small APO again, because they just can’t compete on price. Meanwhile, Chinese-made APOs no longer feature agricultural tubes and focusers, no longer have slow f-ratios.

So when a friend bought a Skywatcher Equinox 80ED, one of the newest Chinese APOs with a spec’ that competes directly with Tele Vue’s much more expensive 76, I couldn’t wait to compare them.

Design and Build

Tele Vue

For a full discussion of Tele Vue’s little 76, see the separate review. Suffice to say that mine is an early one with the gloss anodising and chrome drawtube. In other ways it is much like any other Tele Vue, past and present, with a slim unbaffled tube finished in ivory powder coat, a sliding dew shield with screw-on lens cap and a simple, high quality rack and pinion focuser. The lens specification is fairly ordinary these days, although it was once very fast: a 76mm (3 inch) F6.3 doublet apochromat. Tele Vue have been able to make the 76 very small and slim using their standard approach of replacing knife edge baffles in the tube with a lining of flocking paper, so the tube is the  bare diameter of the lens and no more. The 76 looks lovely: elegant and small and very solid.

The TV76 uses the standard Tele Vue clamshell with its camera thread and TV-mount compatible threads on the base. If you want to mount on a Vixen dovetail, an adapter is available.

The TeleVue comes with a soft case as standard that is easily carry-on portable in any situation.

Sky Watcher

The Equinox ED80 has the same shiny black tube and chrome highlights as the 120ED I own and which is reviewed separately. It’s actually quite a bit longer and fatter than the TV76 and a bit heavier too, but the mounting shoe with its Vixen dovetail and ¼-20 thread means at least you don’t need to add tube rings. The ED80 looks gaudy and plasticky in pictures (at least it does to me), but this is mostly an illusion. In fact the ED80 is almost all CNC-fabricated metal, with just a few plastic parts, mainly in the focuser. The tube is very solidly built and the long dew-shield slides with precision and heft. The interior is very well baffled and matt-black painted, showing care in manufacture in areas which don’t generally show.

The focuser is standard fare for a Chinese APO and isn’t quite the same quality as the tube. It is a Crayford (i.e. the tube is moved by friction, not a rack) and has a dual speed mechanism and a scale on the drawtube that is handy for photographers. It looks a bit cheap and nasty to me, and though it is smooth and precise, it is definitely more plasticky and flimsy than the TeleVue’s and probably wouldn’t be as robust long term. One very nice feature of the focuser is the rotator: loosen the shiny ridged collar and the whole thing turns to give you the best position without risk of dropping your diagonal or camera. However, that ridged collar is chromed plastic and the chrome wears off in heavy use.

The lens on the ED80 has the same look and cell design as the bigger 120, but unlike the 120 the lens is not the same one as the cheaper ED Pro. That scope has a focal ratio of F7.5, but in the Equinox it’s just F6 – a proper fast APO. The lens has a dark green coating (“China Green”, as some call it), that is OK but not as good as the TeleVue’s.

The Equinox comes with a nice (if rather large) hard case.

In Use - Daytime

In use during the daytime, the TV76 has more contrast, less light scatter and less chromatic aberration. The difference is subtle, but you can see it in these two photos which were taken of the same view. The TV76 is a little crisper, with less violet bloom over the branches.

    

TV76

 

Equinox 80

In Use – The Night Sky

With both scopes setup side-by-side in the late winter snow at the end of my garden, where we could catch Mars and the Moon (just one day past full) on the rise, it was already brutally cold and frosty, so this was going to be a fairly swift comparison! The fact that both scopes share the same focal ratio meant that we could swap eyepieces between them to get identical powers.

The first target was the Moon and it was immediately obvious that, although basically similar in both scopes, the view through the Tele Vue was a bit more pleasing. We swapped between eyepieces to give powers ranging from 15x to 120x, mainly TV Plossls, Radians and the Nagler 3-6mm zoom. Neither scope showed much chromatic aberration either side of focus, but the ED80 gave a slight tinge of purple to shadows and the Moon’s limb in focus. What’s more, the Equinox didn’t seem quite as sharp and the Moon’s limb was suffused with a glow of scattered light absent in the Tele Vue, making the view through the TV76 seem whiter and harder and with more contrast.

On the mechanical side, nice though the dual-speed focuser of the Equinox is, it didn’t offer much greater utility than the super-smooth rack and pinion on the Tele Vue (some have said that the more recent satin-tubed focusers aren’t quite as smooth as the chrome-tubed ones and I agree).

If the Moon through the Equinox seemed a bit soft compared to the perfect view through the TV76, 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 TV76, 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 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.

Turning to Mars just after opposition with a disk size of about 14 arcsecs, views were much the same, 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. I couldn’t see much difference between the two, but thought high-power focus was a little snappier in the 76.

Having found the scopes evenly matched on deep sky and Mars, I turned back to the Moon to see if I had been imagining it, but no, the TV76 was sharper, cleaner and with less unfocussed light and better contrast.

I didn’t test the Equinox for astrophotography, but its owner has since shown me some very nice DSLR images taken through it, including a particularly good one of M31 with a lot of detail in the dust lanes and a nice flat field with just a little more violet bloat on O-A stars compared to the same image taken through his FS128.

Summary

If you want a low cost wide-field astrograph, then the Equinox 80 is an excellent choice, with its fast lens and accurate dual-speed focuser. It’s not bad as a grab-n-go or travel scope either, though a bit larger and heavier than the 76.

The owner of the Equinox 80 is convinced that the Chinese will eventually kill off boutique APO manufacturers like Tele Vue. I hope he’s wrong. For one thing, I don’t see any signs of Skywatcher innovating in the way Tele Vue have over the years. Sure, the Equinox has a more polished look than the TV76, has a rotating dual speed Crayford as standard and is a lot cheaper. Shinier and better equipped it may be, but the Skywatcher is also significantly bigger and heavier. The main reason I hope it doesn’t kill the little Tele Vue, though, is the view.

You see, the view through the Skywatcher is OK, good even. But compare the two side-by-side and the Equinox isn’t as sharp, doesn’t have the contrast, has slightly less glitteringly pinpoint stars and shows more scattered light on bright objects like the Moon. For me a small refractor needs to be virtually perfect to make it more attractive as a visual scope than, say, a small SCT or Mak’; the TV76 is, the Equinox isn’t.

The Equinox 80 is recommended as a budget astrograph or grab-n-go, but don’t expect to get (quite) premium APO build quality or view.