The Skywatcher Evostar ED150 DS Pro Is Here !

[Paz]

Thanks John for the time that you have put into these reviews they have been very interesting and helpful to read.

[Anderscn]

If the Skywatcher 120ED is so good, I can’t see why the 150ED shouldn’t be also. The problems with the two scopes should pretty straight forward to resolve by any optical/telescope company.

The 150ED just seems to be rushed out on the market before it was finished.

 

Best Regards,

Anders

Edited August 9, 2018 by Anderscn

[Moonshane]

21 hours ago, Ben the Ignorant said:

That's why people have to learn to center their doublet themselves.

Set all the screws at the same depth on one lens.

Orient the scope so two screws from the other lens are at the bottom and loosen the other screw(s).

Use those two screws like a spring-loaded finder's screws, the weight of the lens will act as the spring force.

Tighten top screw(s) gently.

That's it.

Sounds familiar.....as. Newtonian owner ?

[nightfisher]

4 hours ago, DRT said:

Does it really matter which of those things caused the problem, Jules?

Either of those things should have been caught and fixed by the QA process.

 

No It does not matter and I will drop out of this thread

Edited August 9, 2018 by nightfisher

[DRT]

59 minutes ago, nightfisher said:

No It does not matter and I will drop out of this thread

Whatever I said that caused offence was not intended, but for the life of me I cannot work out what it was.

[John]

I think the issue with the 1st scope I tried was most likely caused in transit, probably in the UK. The scope may well have left the factory in good order. I think what caused the poor star test with that scope was a decentered element in the objective. Apparently, if the optical design of the lens requires quite a lot of curvature in one or more of the lens surfaces, the sensitivity of the lens overall to one element not quite having it's central axis directly aligned with the other element becomes much more critical. The objective cell should be designed to cater for this of course and to enable the scope to survive the sort of knocks that might reasonably occur in transit. More packing around the case and the scope inside would have helped here as well.

With the 2nd scope, it was pretty clear to me that sloppy manufacture and no final QC checking had left the objective lens tilted and the tilted lens retaining ring was evidence of this. There may also be other reasons for the tilt inside the cell which I've not been able to examine. I've no doubt that the scope left the factory this way.

Either of these scenarios is very unsatisfactory. If the scopes optics cannot survive reasonable transport handling then the objective cell design needs to be examined and the packaging improved. If poorly assembled scopes can leave the production line without being picked up then the assembly methods need to be reviewed and the quality checks improved.

The ball is very much in Synta/Skywatcher's court I feel.

 

 

 

[FLO]

7 hours ago, tooth_dr said:

How does the Es Reid test work? Do you keep checking scopes until you get one that ‘passes’ or is one scope adjusted (if needed) until it passes?

No. We send a telescope to Es’. He puts it on his bench for assessment. If he finds an aberration/fault that can be adjusted out then he does that. If it cannot be corrected then the telescope is rejected and returned to the distributor or manufacturer. We then send him another. Es’ does the clever stuff, we just move telescopes around ?

HTH, 

Steve 

[nightfisher]

42 minutes ago, DRT said:

Whatever I said that caused offence was not intended, but for the life of me I cannot work out what it was.

Derek, think you misunderstood my reply and looking back i worded it incorrectly, just a case of i cant add any more to the thread, probably all the painkillers i have taken today for a bad back....ignore me

[John]

34 minutes ago, nightfisher said:

Derek, think you misunderstood my reply and looking back i worded it incorrectly, just a case of i cant add any more to the thread, probably all the painkillers i have taken today for a bad back....ignore me

Hope your back improves Jules. They can make one a bit grumpy, I know from experience

[Stu]

2 minutes ago, John said:

Hope your back improves Jules. They can make one a bit grumpy, I know from experience

Indeed backs are rubbish! Very grumpy making at times. Hope it improves soon Jules

[DRT]

2 hours ago, nightfisher said:

Derek, think you misunderstood my reply and looking back i worded it incorrectly, just a case of i cant add any more to the thread, probably all the painkillers i have taken today for a bad back....ignore me

No problem, Jules - I hope your back improves soon.

[Special K]

I’m pretty surprised by the quality issues as the ED range has a good track record. 

Just a silly question because I don’t have experience of using cheshires:  on the first scope, the collimation check appeared to be ok but then failed the startest.  Is that to be expected?  I’m assuming a star test is more revealing than a Cheshire test.  Or was it possible the collimation was ok per the Cheshire but it could not detect the likely bent tube?  I just thought a Cheshire would have identified the misalignment of the overall system.  Sorry if I’m being dim!

 

[John]

2 hours ago, Special K said:

I’m pretty surprised by the quality issues as the ED range has a good track record. 

Just a silly question because I don’t have experience of using cheshires:  on the first scope, the collimation check appeared to be ok but then failed the startest.  Is that to be expected?  I’m assuming a star test is more revealing than a Cheshire test.  Or was it possible the collimation was ok per the Cheshire but it could not detect the likely bent tube?  I just thought a Cheshire would have identified the misalignment of the overall system.  Sorry if I’m being dim!

 

The cheshire test only establishes whether the objective elements are purpendicular to the optical axis of the scope, if they are not the "tilt" shows through the reflections of the illuminated cheshire eyepiece face not being aligned. Before you do the cheshire test you should establish that the focuser optical axis is true with the centre of the objective, using a collimated laser, because focuser tilt can cause the cheshire test to be poor. Having eliminatated focuser tilt and objective tilt with the 1st scope I was expecting a decent star test but it was not too good as I recorded in the report. Establishing the cause of this is more complex because you would need to remove the objective lens and check a few things such as an incorrect or uneven air space or one element having a degree of "wedge" to it - the latter is quite rare with modern production I think.

The other thing that can cause a poor star test is where the central optical axis of the 2 objective elements have become mis-aligned. This is known as de-centering. It can be adjusted out through the 12 centering hex screws (6 per element) which are under the felt covering around the edge of the lens cell that I showed in my photos. Sorting out these latter issues would have required breaking the seals holding the objective retaining ring in place which I felt was well beyond my remit with these scopes - they did not belong to me after all !

The laser and cheshire tests would have picked up on a bent tube as well but there was no sign at all of that with these scopes - they were pristine cosmetically.

 

[Special K]

Thanks for explaining that John!  (I should get some of these doohickies one day but I just trust to star testing for now) 

Something makes me think that dealing with smaller objectives is easier and that the problems increase exponentially with larger refractor lenses. That’s just a hunch based on the exponential price points on 6” scopes!  In the case of this scope Skywatcher have tightened the budget a little too far to account for proper QA at the point of assembly. 

I still hold out a lot of hope for this design and look forward to news of the comparisons we are keen to hear about. I suppose the biggest comparison for me is how it will weigh up against your ED120.

As a consumer, I would be thinking in this vein:  if I wanted a SW ED design and quality was pretty equal, it would all be about aperture and size with the cost this brings.  My assumption would be that I’d be getting a bigger version of my proven ED80. I think the one thing that could sway me in favor of a shorter focal length (such as my f/5.9) is the smaller FOV.  Having said this, f/8 seems to be the most popular.  Ultimately, I’d like to see how this stacks up against the Starwave 152.....I could be in for a long long wait!!!

[John]

For what it's worth, I think the Skywatcher ED150 will be a really good scope and excellent value for money, in due course. What I have encountered with the 2 scopes that I have tried are teething troubles which I'm sure Skwyatcher and their importers will address. Quite a few other scopes went through similar troubles in their early days but are regarded as very good now.

The great thing for the amateur astronomer is that there are forums such as SGL where these issues are highlighted and discussed openly. This had been a very important development in the past decade although the manufacturers might not always agree !

 

[Alan White]

15 minutes ago, John said:

The great thing for the amateur astronomer is that there are forums such as SGL where these issues are highlighted and discussed openly. 

Oh yes indeed, forums are a great way of keeping things in the open and some manufacturers honest*.

*(This applies to all walks of life and hobbies and is not aimed at any manufacturer specifically).   The lawyers said put this qualifier in ?

[John]

I would not suggest that manufacturers are anything other than honest.

[Special K]

I appreciate the headache this has involved for you and it’s not an outcome any one would have expected. Nevertheless, I look forward to the final verdict once you get your hands on the real goods!!!

[nightfisher]

20 hours ago, Stu said:

Indeed backs are rubbish! Very grumpy making at times. Hope it improves soon Jules

Stu, John, Derek, i think the good wishes are beginning to have effect, so thank you all, starting to feel a little more my old self ? 

[John]

As an addition to the reports on the two examples of the Skywatcher ED150 scopes that I have reported on above, I've had a look through the issues folks raised in my the thread posted before the scopes arrived:

 

I think a number of the issues raised were covered by my reports but I've picked out some others and, where my testing has allowed, I've tried to provide some sort of response. Optical testing was not as thorough as I would have liked due to the optical issues with the scopes (particularly the 2nd one). If I get a chance to have a 3rd ED150 I will examine a wider range of optical performance issues in more detail.

Meanwhile, I hope this additional information is of some interest (the issue raised is shown in bold italics):

- Balance point (how front end heavy- your pics will surely show this!)

Here is a photo of the scope at balance on the Giro Ercole mount with no tension on the altitude axis.

- Mechanical quality and utility of the focuser (is the tension easily adjustable)

Seems pretty good. As good as any stock Skywatcher focuser that I’ve used. There is a single tension screw underneath. Held a 500g eyepiece in a 2 inch diagonal when the scope was pointed close to the zenith, without any focuser creep being noticed.

- Mechanical quality of tube rings and dovetail (is an upgrade advisable?)

They seem very similar to those supplied with the Evostar 150 F/8 achromat. Up to the job but not deluxe. For imaging or simply maximising stability the heavy duty CNC tube ring / Losmandy dovetail bar set is available as an optional extra at £188.00.

- Comments about the lens cell (does it look robust?, presence of collimation screws)

I think my findings demonstrate that the lens cell might not be as robust, at least while the scope is in transit, as might be desirable. The cell does not have a tilt adjustment facility but the centering of each lens element can be fine tuned through 6 hex screws (per element) arranged around the cell. Better packaging of these scopes while in transit is being arranged I understand, which will help. The objective cell is a similar design to the ED120 externally. I have not been able to examine the details of how the objective lens is held within it.

- if a GPD2 mount would be up to the job for visual and how easy it is for one person to get on and off the mount.

I’ve not had a chance to use my Vixen GP DX mount with the scope but the way that the Giro Ercole handles it, I’d say that the GP DX would do a good job for visual observing. For imaging a much more sturdy mount such as an EQ6 / Losmandy G11 would be needed. I found the scope relatively easy to mount and dismount on my own.

- Levels of field curvature

Not really tested I’m afraid. Something for the next example of the scope, if I get one.

- Whether it's likely to be ok for visual on EQ5 and a giro mount or would it need a HEQ5.

Possibly OK for visual if the EQ5 is mounted on either a 2” steel tube tripod (ef: EQ6 or CG5 tripod) or a Berlebach Uni. It was quite good on the Giro Ercole if 3-4 second damping times are OK for you. An HEQ5 would improve on both of these I would think.

- Is there adequate in focus for binoviewers.

As supplied there was only 20-25mm of inward focuser movement left when the scope was at focus with my Pentax XW eyepieces in a 2 inch diagonal so I have some doubts whether a binoviewer would come to focus either with the barlow fitted or without it or if used with a 1.25" diagonal. I will try this again if I get another scope to report on.

- If you still have the lunt wedge I'd be interested to hear your thoughts.

I did not have the chance to try this but I would be wary that the 150mm might be a touch to much apeture for comfort with my 1.25” Lunt Wedge.

- any slop in the focuser when loaded with a heavy diagonal and EP or the binos.

Binoviewer not actually tried. The focuser did not show any slop with a 2 inch diagonal and 500g eyepiece fitted in the drawtube.

- I would be interested to know how easy it is to remove (unscrew) the dew shield.

I managed to unscrew the dew shield, using 2 hands, with both the examples of the ED150 that I have tried. It takes a little effort to get it started but once moving it unscrewed easily. Putting it back on needed care not to cross the thread cut into the objective lens cell but it was not too difficult.

- I take it the focuser is the same as on the other Evostar ED Pro fracs?

Yes, it looks the same white dual speed unit.

Again, thanks for all the interest you have shown in my reports on these scopes

I hope that my story does not end there and that I get another chance to put a Skywatcher ED150 DS Pro through it's paces in the near future. I will start a new thread then - this one has become rather long !

[DRT]

Thanks for taking the time to post that, John. Pleasing to see there are no negative comments in this part of your review, which backs up the general feeling that this can be a fantastic scope at the price once these initial problems with the lens cell and packaging are resolved ? 

[recceranger]

Wow, 

We got emotional during this thread! Thank goodness we’re back on point.  

Before I run out and purchase an ED150 - are the optics the same quality as the ED80 - 120 range of DS Pro?

[John]

1 hour ago, recceranger said:

Wow, 

We got emotional during this thread! Thank goodness we’re back on point.  

Before I run out and purchase an ED150 - are the optics the same quality as the ED80 - 120 range of DS Pro?

I compared the 1st ED150 to my ED120 in the performance report section:

The colour correction of the ED150 seems potentially as good as the ED120 but the ED150 optics were not "on song" probably due to a knock in transit. A replacement has been provided but that one had optical issues as well so I have not got as far as comparing it with other scopes.

Hopefully an optically sound ED150 will be in my hands in due course so that I can continue with the testing and comparing

[recceranger]

Thanks John

[FLO]

On 11/08/2018 at 18:45, John said:

I hope that my story does not end there and that I get another chance to put a Skywatcher ED150 DS Pro through it's paces in the near future. 

Oh you will, definitely. Our job here isn't done until you have a good working example to assess over time ?