The Sky-Watcher Esprit-ED100 quintuplet refractor – a real cat amongst the pigeons!













At the New Forest Observatory I have the most stunning refractor to review for Kieron at SCS Astro.  I have not been very happy with the Takahashi Sky 90s, mainly the difficulty in collimating them, and then the not too good performance even when collimated.  Specifically, even when collimated there is typically coma in the far corners of an APS size chip which is more than a bit annoying when the spec says that the imaging circle is a full 45mm with the reducer/flattner meaning it should actually fill a full-frame chip no problem.  My dissatisfaction with the Sky 90s, and hence my lack of progress with the mini-WASP array project has been extremely frustrating and led me to look for alternatives to the Sky 90 to populate the mini-WASP array.  Now having done my homework a couple of years back I was pretty much aware that there was nothing in the market refractor-wise that would help me out here.  However, not expecting any joy whatsoever, I asked Kieron at SCS Astro whether there was anything new on the market that could possibly suit my application.  Unbelievably a new scope from Sky-Watcher had appeared on the scene just a week earlier!  This looked like a very exciting new product indeed and Kieron has very kindly shipped me the brand new Sky-Watcher Esprit-100ED quintuplet refractor to review – wowser 🙂

The real joy and appreciation of a job really well done started as soon as I had opened the cardboard box – seriously.  Take a look at the first photo – there’s the Aluminium padded case holding its precious cargo – nothing new or novel in that – but now look closer.  The Aluminium case is suspended from an outer metal framework by 8 powerful springs!!  Oh yes – these guys know what they’re doing alright and they’ll be no cries of “it must have lost collimation in the shipping” with the care that Sky-Watcher have taking in packing their precious goods.  Well done guys, there are a  number of telescope manufacturers out there who could really take a leaf out of your book.  I am highly impressed.

Be careful removing the refractor from its case – it is heavy.  The bare OTA with no accessories at all weighed in at 6.3kg on the bathroom scales, but this is not “wasted” weight, this is precision-engineered sturdiness.  That 11:1 focus controller is silky smooth and there is absolutely no slack or slop in the drawtube assembly which feels like it could support a tank.  Looking down the business end of the scope is like looking into a black hole – absolutely no sign of reflection or light scatter from the inside of the OTA at all – even the flash used to take the photo got swallowed up in there.  The baffling looks superb.

Well, those are my immediate thoughts on taking this amazing piece of glass out of its box and any further discussion of its performance will now have to wait until I have completed the optical tests.  We have a 5-element objective here (hence the quintuplet) that is claimed to give zero detectable colour fringing.  The scope itself is f#5 giving a focal length of 500mm with the 100mm aperture – absolutely perfect for my applications and my M26C one-shot colour 10-Megapixel CCD.

O.K. let’s not beat around the bush any longer, what have we got here?  We have an FSQ-106 equivalent spec refractor (well 6mm off the aperture is neither here nor there) at less than half the price of the Japanese offering.  If Sky-Watcher (Chinese) have got the optical design right (and I have absolutely no reason to doubt that they have) then they have a potential “Tak-killer” on their books – and jolly good luck to them.  My main worry before trying the scope out for real is the possibility of lens flare from very bright stars due to all that glass – but I am pretty sure these guys have already thought of that and have that covered, but we’ll soon see anyway.

Keep watching the NFO site to see the next exciting installment on the Sky-Watcher Esprit-100ED quintuplet refractor review 🙂 🙂


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6 Responses to The Sky-Watcher Esprit-ED100 quintuplet refractor – a real cat amongst the pigeons!

  1. Stephen Collie says:

    I read your preliminary review and impressions of the Sky Watcher 100ED Triplet and would be very interested in hearing about how it performed. I do realize this is nearly 18 months past but Sky Watcher has since discontinued the 100ED 5 Element quintuplet and replaced with a 3 Element Triplet with an screw-on, 2 Element field flattener? I have contacted Sky Watcher without response – was the 100 Quintuplet problematic? Only 2 reviews of the Esprit series exist, the 120 and 150 although positive. Why would a manufacturer release a new line, boast about its optical perfection then pull one of the models from production

  2. Greg Parker says:

    The 100ED Quintuplet (5-elements) was fortunately sent to me on a sale or return basis – I returned it! Physically it was extremely well constructed and I was very sorry to return it as I wanted 2 of them for my mini-WASP array. Several problems, pinched optics, oily swarf from inside the OTA which fell onto the objective and stuck there – but the main problem was an unidentified optical issue which made all stars blurry with a bright halo around the edge. No chromatic aberration worth talking about, but I don’t think Sky Watcher had given any thought to the difficulty in collimating a short focal length 5 optical element system. Basically I personally don’t think it can be done in a time short enough for practical manufacture. I know how hard it is to accurately collimate just the two lenses in a Sky 90. Three lenses is going to be VERY tough, and 5 lenses is going to near nigh impossible. They pulled the 100ED Quintuplet because it couldn’t make spec I would imagine, great shame.

  3. Stephen Collie says:

    Hello Greg,

    Thank you for the information. Another inquiry to my SkyWatcher distributor and a dealer drew a blank about the accessories included in the Esprit 100ED triplet package. One said, no diagonal, the other said it is included. One said finder scope isn’t included, the other said it is. One said field flattener is an option, the other said it is included. While not interested in eyepieces, one said 28mm 2″ eyepiece is included, the other said it isn’t. Surely not a class act for poker-faced SkyWatcher – so a Televue NP101is appears to be the more expensive but logical alternative.

  4. Greg Parker says:

    Hi Stephen,
    You made the right decision. Until SkyWatcher and their distributors can find a bit of professionalism and quit acting like a 3rd world outfit they will continue to lose customers such as yourself. Great shame really as it wouldn’t take very much effort to not only create a first-rate product but to also sell it with pride.

  5. Stephen Collie says:

    Hi Greg,

    I spoke to a SkyWatcher representative today and claims the Esprit 100ED Triplet is popular and gaining acceptance (I still don’t know of anyone who owns one) a redesign of the Equinox 100 SFS Quintuplet is underway. No date yet on release. Knowing SkyWatcher if and when this happens, it will suddenly appear and none of the dealers will have any more information than their customers.

  6. Greg Parker says:

    Strange the way they go about business 🙂

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