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raanany

Sky Watcher 18" StarGate first review

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Hi folks. Some of you may remember my post from a few months ago where I asked for advice on eyepieces

Well, the scope has finally arrived and I’ve been out with it twice.

I’d like to share my impressions with you.

Build quality

While I wasn’t expecting iPhone quality fit and finish from an 18” telescope, I was hoping that for NIS 21000 (GBP 3500, USD 5335) I’d get something of higher quality. Materials are cheap and I was disappointed to find the following:

The four base mounted brackets comprising the bearings on which the two arched rails rest, were not accurately spaced. The distance between the rear pair was about 3mm narrower compared to the front pair. The front pair was correctly spaced but the rear one was too narrow. This caused the arched rails to get stuck. Friction was too high and it made the scope jerky to maneuver despite ample application of the supplied lubricant (vaseline).

IMG_0055.jpg.4df437dad18fd6d5ee4d7ce60f4 IMG_0057.jpg.7c22fd719b48348f6e2b0898aa7

After making some measurements I noticed I may be able to improve things by opening the screws that hold the brackets and moving them by as much as the frame will allow (very little). This didn’t eliminate the problem completely as I was only able to widen the spacing by less than a millimeter. However, it did change things from being marginally useable to just acceptable. I assume that with wear and tear the silicone pads on these brackets will slowly fit the metal arched rails better.

The manual obviously doesn’t say anything about the need to do this and I assume it’s simply the result of poor manufacturing precision and even poorer quality assurance.

The black plastic shield protecting the primary mirror is a joke. It’s made of the thinnest plastic you could think of and is flexible instead of being rigid and protective. Also, instead of hanging on to the mirror box it just rests there and can easily move or fall off. There’s a padded foam clumsily glued to its inside but it’s thin and I wouldn’t want to count on it for protection should the cover get pressed or moved. I was expecting a rigid cover that screws on to something and keeps a safe distance from the mirror it’s protecting rather than this sorry excuse. It will protect against a falling screw but don’t expect it to do much more.

IMG_0062.jpg.521f750e1bf7f4376e5eadb88b3 IMG_0063.jpg.e06cdd0e895759dfd099d1dd3c5

The Mirror with the metal part it’s mounted on are pretty heavy weighing around 22Kg and with its sharp edges should be handled with great care. If the plastic cover protecting the primary was as I expected, you could potentially hug the whole thing to your chest making it easier to carry but being so flimsy, you’d be smearing the “protective cover” all over the primary mirror if you did that. Instead you’re left with holding the mirror box like a huge and very heavy dinner plate projecting from your body. Not very easy.

All metal parts are made of cheap low quality metal. You won't find any high quality steel screws. The screws tend to jam and require pre-emptive lubrication. They are of such low quality that when I tried to unlock the secondary mirror in order to collimate it, the main screw’s head couldn’t handle the torque the screwdriver stripped the screw's head. Keep your shirt on, I know how to handle a screwdriver. I ended up buying a kit to drill it out. Picture attached.

IMG_0073.jpg.9b2e3c23edc28d6c4dc229bd0e5

Optics

This is where my opinion should be taken with caution. I’ve never looked through a telescope for more than a minute and even that was on 8-10 inch looking at the moon at company events.

With the StarGate, I had a look at the orion nebula, Andromeda Galaxy and of course, the moon. Andromeda looked like an elliptic cloud with a bright center. I couldn’t detect the spiral I was hoping to see. Could also be my eyes or lack of patience and experience. The orion nebula was quite beautiful. 

IMG_0069.jpg.9a46421971621eb5ef6a69f42c8

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Very interesting report. So its not all up &

running,  out of the box. Built to a price,

like every thing else, now days. :happy9:

 

Steve.

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Good to read a report on one of these, but clearly with issues. Great if you could continue to post any follow on observation / performance accounts and if you are able iron out any further initial problems.

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A different design concept of cause, yet a big leap in cost over a 400 flextube. As said, hope you can resolve the somewhat impracticable questionable design features and get favourable use out of this, expect that the mirrors will / ought to be very good.

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You can get a good quality 16" Lightbridge for £1900, a Lukehurst standard 18" for £3600, and a Summerian 16" Alkaid for £3200. For the price of the Stargate, and the quality intimated in this review, it's difficult to see where exactly Skywatcher are trying to compete with their new truss dob in the market place.

The mere hint of plasticy bits, and mods on essential working parts, would put me off for sure. At five hundred quid shy of four grand I think they are gonna realise that folks spending that sort of cash are a bit more discerning and demanding on quality, even if it is built to a price.

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Keep in mind you'll never be able to see the Andromeda galaxy as a spiral with a 18 inch scope. It's much bigger than the widest possible field of view with any eyepiece. What you observed is just the galaxy nucleus.

Be patient. A huge dobsonian is not exactly the kind of telescope I'd recommend to someone without a considerable amount of observing experience.

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It's very surprising and disappointing.  I've always found SW kit well put together, built to a price but perfectly functional.  What you've shown seems well below that standard.  I too would be interested to here updates.  BTW  the spiral structure of M31 is  a challenge even with an 18" scope unless you have a nice dark sky.

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Interesting review, thank you, Raanany.

I have the smaller brother (400p) which is built like a tank. I was thinking about getting a Stargate if my ship came in, but might have some second thoughts.

As a further comment, one or two frontal elliptical dust lanes in M31 can be seen in skies around Limiting Magnitude 5.5 and darker.

 

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Yeah, those build quality issues are hugely disappointing. There are not many reviews out there but so far I had read it's an excellent design. However this seems to be similar to what it's reported from Explore Scientific dobsonians.

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Not seen much detail in mine either!....I'm shocked at the quality of this scope for the money... Mine cost about the same as this and the build quality is rock solid with optics hand made by a craftsman. o

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12 minutes ago, Thonolan said:

Yeah, those build quality issues are hugely disappointing. There are not many reviews out there but so far I had read it's an excellent design. However this seems to be similar to what it's reported from Explore Scientific dobsonians.

The nearest ES scope is less than half the price of this though!  I would much rather have a Sumerian for my money based on this review. Most upsetting as its a considerable sum for a scope.

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5 minutes ago, Mrbloke said:

  I would much rather have a Sumerian for my money based on this review. 

nah you wouldn't trust me.

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That's a shame. 

To reiterate what someone else said earlier, I see dust lanes in M31 with 16" and NELM 5.5-5.6

Barry

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Very honest review.
Definitely some build issues with this scope that SW needs looking into. Doesn't make for pleasant reading to know that customers paying considerable money are finding serious build issues like this. There's just no excuse for the junk screws you describe (keeping my shirt fully on :) I have experienced these type fixings myself). You kinda expect them on a cheap toy, not a £3500 flagship Dob from SW. Very disappointing......

 

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6 hours ago, raanany said:

I’ve never looked through a telescope for more than a minute and even that was on 8-10 inch looking at the moon at company events.

Welcome to SGL :smiley:

Is this really your first telescope? If it is then you have jumped into the deep end. 

First things first, are you confident you have achieved collimation and allowed enough time for the mirror to cool to ambient temperature? 

I wonder what type of mirror is fitted to the telescope when sold in Israel. If you are able please post a photograph showing the rear of the mirror, we will then know if it is the early cast mirror or the more recent fused together mirror. 

I agree with the others, your experience regarding assembly is rather disappointing. 

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Thank you for the honest report. I hope you get a chance to try the scope out under good skies. M31 shows detail, in particular dust lanes but for spirals try M51 under dark skies.

Gerry

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2 hours ago, estwing said:

Mine cost about the same as this and the build quality is rock solid with optics hand made by a craftsman. o

Oh dear.. don't tell me this things! You are seriously tempting me for the future! 

 

To the Original Poster. Thank you for sharing your honest review. I cannot help agree with the previous posts about the fact that one should deserve much more for that price. In the case that you bought new, is there a chance to return it and get something else (maybe for the same price)? Just an idea of course.

Edited by Piero

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Hi there  that's crazy for that money  I would exspect good quality at least and if you do not mind me saying. A good gust of wind and it looks like it would fall over ,and boy it's ugly looking as well ,that said am sure the views are good with this scope am sure you will learn to love it 

pat

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i agree with bart, pat dont mix your words :happy7:realy feel for you though raanay, whats your next move, are you going to return it or keep it ?

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Hi,

Sorry to hear about your disappointment with the 450p & thanks for posting your review.  If the spacings are incorrect for the altitude bearings to run true, then I'd suggest contacting the supplier and reporting this (along with your other findings).  It may be important to do so before attempting mods - in case you are ultimately not satisfied ... it's a lot of money.

I had looked long and hard at this scope on the web a year and a half ago, and had been very tempted! I would have expected better from Skywatcher tbh. Personally, I thought it a good looking scope; and with the size of those alt bearings, had hoped it was a sign that care was being taken in the design to ensure smooth motions and balance. These are really key to the enjoyable use of a manual dob.

That mirror cover looks flimsy - if I remember correctly, someone reported the foam detaching and flopping down on the edge of the mirror - leaving a residue on the mirror surface. I see it coming away in your pic - watch out for this so - no one wants to have to clean glue gunk off a brand new mirror!!

Re Andromeda, I see 2 dark dust lanes in my 250px when cooled, collimated and dark adapted on a decent night.  You need a large fov for Andromeda - what EP were you using?

Best of luck, and keep us posted on how things go with the scope,

-Niall

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Thank you for this review. Often we see reviews that compare what you see through the scope, which is also important. But you describe the quality of the construction, which is equally important.

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