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The Skywatcher Evostar ED150 DS Pro Is Here !


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34 minutes ago, Saganite said:

I should hurry up John, the Big 40....000 is looming and if you become a Black Hole, your results may never reach us.:happy11:

Looks better tonight so hopefully a good session with the ED150 and friend will ensue. Jupiter is in their sights just now:

 

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49 minutes ago, Saganite said:

I should hurry up John, the Big 40....000 is looming and if you become a Black Hole, your results may never reach us.:happy11:

Shame, a first light post to celebrate the 40k would have been very apt but let’s not wait for that :)

Looking promising John.

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4 hours ago, John said:

Here are some more pics of the objective and it's cell. The dew shield unscrewed easily so I was happy to take it off for a few minutes. Beneath the felt tape I can feel two sets of 6 holes, presumably with hex screws in them to hold the lens elements in position. No foil lens spacers visible so I assume that the air space is maintained with a thin ring between the elements.

The coatings seem really nice quality with that strong purple tinge previously described. There seem to be 4 knife edge baffles in the scope tube. The focuser drawtube is matt black and has micro grooves along it's interior.

I've checked the objective tilt using a cheshire eyepiece and it seems spot on with just the single reflection of the cheshire face bang in the centre of the objective (you get 2 over lapping images if the tilt is out, 2 separate ones if it is very much out). A collimated laser beam shone down the tube exits the centre of the objective so the central axis of the focuser seems to be in line with that of the objective.

 

 

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Don't  you just LOVE a big lump of purple coated glass??!!:hello2:?

Dave

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3 minutes ago, Tim said:

You must know we are all checking the weather in your part of the country John :D

I'm just digging my way through the snow drifts to the scopes Tim :grin:

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Although I'm not in the market for one (two maybe!) I really hope that it will be the success it promises to be on paper. As an ex vendor I'm sorry to see the discounting in operation even before the telescope has had suitable reviewing. It was commonly acknowledged to be an absolute bargain potentially at the original price, I don't think those unable to afford one are likely to invest given a few % off. Surely the time for discounting would be more sense if the telescope turned out to be disappointing.

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14 hours ago, F15Rules said:

Don't  you just LOVE a big lump of purple coated glass??!!:hello2:?

Yes, and not just for the looks. I've read countless reviews where they say they love the typical chinese green coating on Sky-Watcher lenses, but green is the color the eye sees best, whether in the dark or not. I've even seen yellow-green coatings on some binocular prisms, these are the least likable. Amber is more or less acceptable depending if it's brownish or orangish. Red is not common but very good, reflections are very faint.

Deep blue, indigo and purple are excellent. I've almost never seen a parasitic reflection in my Baader Phantom-coated eyepieces, and they have no green coating. Unless it is the very dark forest green type, green is liable to cause dancing fairies in the eyepiece when viewing Venus or Jupiter. I don't believe reflections from the objective can be seen as dots in the eyepiece, but scattered light can.

So, one more good mark for the new big 150.

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Thanks for your patience folks. I am working on something to post later today. I've a few pages of rather rough notes to mould into something vagely readable :smiley:

My other half seems to have some other priorities for me in the daytime as well - very unreasonable ! :rolleyes2:

 

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20 hours ago, John said:

Ok, the issue of scope balance has been raised quite a bit.

The photo below shows the scope (minus an eyepiece and the dust cap) at perfect balance on the Giro Ercole mount with no tension on the altitude axis. The dew shield unscrews quite easily so I was able to weigh it on it's own at 950 grams. Apologies for the cluttered photo - life goes on here despite the large refractor taking up most of the dining room !

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Sorry to be a pain John but I can't recall you ever saying you needed dew prevention despite having plenty fraks. Could you do the same pic with some thing like dew tape weight wrapped around the objective or even a camping mat extending the dew shield? Not sure if you have these ? If they put their logo in near the same place as the older fraks then it does seem to sit far better in the rings than my collimateable EVO150 did. 

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2 hours ago, Ben the Ignorant said:

Deep blue, indigo and purple are excellent. 

I agree that Deep Purple are excellent - especially the Perfect Strangers album!?

But seriously, all the Russian scopes I have seen, like Lzos,  Lomo, Intes Micro & Tal, and Russian binoculars like Zomz, Tento etc have had purple coatings - and they have all had excellent optics. Can't be a coincidence!

Dave

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1 hour ago, spaceboy said:

Sorry to be a pain John but I can't recall you ever saying you needed dew prevention despite having plenty fraks. Could you do the same pic with some thing like dew tape weight wrapped around the objective or even a camping mat extending the dew shield? Not sure if you have these ? If they put their logo in near the same place as the older fraks then it does seem to sit far better in the rings than my collimateable EVO150 did. 

I only use a dew shield with my ED120 when I'm observing away from my back yard. I don't seem to have dew issues here so I just have a light Astrozap ED120 dew shield extension. I don't have a dew shield that will fit the ED150. Sorry about that.

Having owned collimatable and non-collimatable examples of the Evostar 150 F/8's I know that the collimatable objective cell added a fair amount ot top end weight to the scopes which pushes the centre of gravity forwards quite noticably. Both the fitted dew shield and the objective cell weigh less in the ED150 than I would think.

If you can let me know what the dew equipment that you mention might weigh in total, I can see if I can add a suitable weight to the top end of the ED150 and see how that effects balance ? :smiley:

 

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Ok, here goes with my first performance report on this scope :icon_biggrin:

I’ve had two sessions with the Skywatcher Evostar ED150, one of a couple of hours under patchy clouds and moderately stable seeing and last night under very thin clouds but steadier seeing. Transparency on both nights was OK but not that special, between the clouds. In total this amounts to around 5 hours observing time.

I used my Skywatcher ED120 refractor as the comparison scope on the same mount as the ED150 so that I could quickly switch between the two scopes. During the first session I used Pentax XW eyepieces (10mm, 7mm, 5mm and 3.5mm) plus the 24mm Panoptic for lower power views selecting focal lengths to give roughly equivalent magnifications. On the second night I used my 7.2-21.5mm zoom eyepiece and Baader 2.25x barlow with both scopes for a mix of high and low power views.

Within the Solar System I observed Jupiter, Saturn and Mars. Stellar targets included Vega, Deneb, Altair and Polaris for star testing and colour control assessment. Double star targets included Epsilon Lyrae, Delta Cygni, the very challenging Lambda Cygni, Iota Cassiopea and Pi Aquillae. Deep sky targets included the bright galaxies M31, M32, M81 and M82, planetary nebulae M57 and M27, globular cluster M71 and the “Double Cluster” NGCs 869 and 884. These are popular targets at this season here and I observe them frequently so have got to know them reasonably well.

In use, the Skywatcher ED150 is, for a large aperture F/8 refractor, a reasonably easy to handle instrument. It’s not as daunting as I expected to move it about and to lift it on and off of the mount, provided that some care is used and the mount properly balanced and locked before fitting the scope.

Once mounted on my Giro Ercole alt-azimuth mount on it’s Berlebach Uni 28 tripod I found that I could lift the whole setup (including the ED120) and move it (carefully) around the garden to get the best views. Quite important in my circumstances here !. The tall tripod meant that I was able to get the eyepiece to a reasonable height so even when observing near the zenith with the long tubed refractor (more or less where Vega was at this time) did not require too many contortions.

Dew is not a great issue in my back yard at this time of year so the dew shield efficiency was not really tested – clear views for the whole time !.

The ED120 on the other side of the Ercole mount was acting as a good counterweight so mount movements were smooth but without that I reckon a weight of around 5-7kg would be required when the ED150 was used solo to ensure nicely controlled movement of the scope with this mounting arrangement.

The dual speed focuser on the ED150 handled my eyepieces in the 2 inch Tele Vue diagonal smoothly and I did not experience any focuser “creep” even when observing near the zenith with a 400g eyepiece and 600g diagonal in the scope drawtube.

When the ED150 was at sharp focus with the eyepieces that I was using, quite a lot of inwards focuser travel was used resulting in between 10mm and 20mm further inwards movement remaining.

So the scope is straightforward to use and works efficiently. Very similar to the ED120 in fact. But what are the views like ?

As I reported earlier in this thread (see the unpacking photos) this scope had clearly received a reasonably heavy blow at some point during transit, causing the scope tube to shift within it’s case enough for the camera mounting screw on one of the tube rings to punch it’s way through the foam, thin ply and aluminium layers of the case. Naturally I have been concerned as to whether the optics had been affected by this incident.

I performed star tests on a number of stars at 300x magnification over the two nights. I examined the star image at sharp focus and then it’s appearance as I racked the focuser slowly through focus. I also performed the same tests with the ED120 refractor at around 250x. I used 3 different diagonals to verify the results.

The ED120 showed an excellent star test as it has for all the years that I have owned it. Concentric diffraction rings at focus and a very similar and evenly illuminated diffraction intra and extra focal patterns with a thin purple fringe around the intra focal image replaced by a thin pale green fringe in the extra focal image. No CA visible at focus with Polaris, just a tiny splash of violet with Vega, Deneb and Altair. A single thin diffraction ring at focus around mag 2 stars, a further faint ring with mag 1 or brighter stars. Classic ED doublet results I feel.

The ED150 sample that I had mirrored the colour correction performance of the ED120 in these same tests. The glass selections used in the ED150 objective differ from the ED120 but are clearly doing a pretty good job of controlling the chromatic aberration. Where my example of the ED150 did not do so well was the pattern of diffraction rings at focus. The rings were clearly not concentric and were biased to one side of the airy disk. Another issue (quite possibly linked) was that the intra and extra focal images of the ED150 were slightly brighter on one side, the opposite side to the splay of the diffraction rings at focus. The illustrations (not images) below are black and white approximations of the high power star test of this particular ED150, firstly at focus and secondly either side of focus:

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A further effect that I noticed was that the extra and intra focal star images had a very slight hexagonal form to the outermost ring of light. This was very subtle though so not shown in the above approximations. The diffraction rings did seem concentric and were of pretty even brightness either side of focus, but not at focus where the offset described above becomes apparent.

I am not an optical expert so I can’t diagnose these star tests precisely. The test star was very close to or at the centre of the field of view at all times. Using the ED120 star test as a comparison showed that something was amiss with the ED150 optics, quite possibly caused by the impact that the scope had suffered during transit.

Despite the above, the ED150 had no problems in splitting the double stars listed cleanly with the exception of Lambda Cygni which is a very challenging .92 arc second binary. I got a peanut shape with both scopes though the 150 showed a narrower “waist”. The other splits were reasonably comfortable with both refractors but I have to say that the ED120 produced tidier, cleaner star images with the less than ideal ED150 star test not helping it’s cause here.

The planetary views though both scopes were very similar.

The ED150 could bear a higher magnification on Jupiter than the 120 – I found the former produced clean views at 225x whereas 180x proved optimum with the latter, smaller aperture refractor. The Great Red Spot was in transit and had good colour in both scopes with the ED150 providing a brighter image (as you might expect) and slightly stronger tints. The uneven edges of the North Equatorial Belt were clear in both scopes as were 2 or 3 festoons crossing the Equatorial Zone. The number of lesser belts visible and their definition was about equal in both the scopes. Perhaps, again, optical misalignment was holding back the ED150 slightly ?

The Galilean moons were clearly defined tiny disks in both scopes with the differing apparent diameters discernable.

Neither refractor showed any false colour to my eye around Jupiter.

Saturn was a joy with the ED150. Here the additional aperture did seem to have some benefits and the C or Crepe Ring was showing itself regularly while it was only glimpsed occasionally with the 120. I managed to pick out small icy Enceladus with the 150 but could not with the 120. So the 150 “won” 6-5 on the Saturnian moon score !.

Cassini’s Division was well shown around the rings with both scopes but tracing it where the rings are narrower (due to perspective) was a little easier with the 150. In both scopes I found 250x worked well on Saturn and, as with Jupiter, no false colour was visible surrounding the planet.

Looking really critically at Saturn, the only area that I noticed where the ED120 produced a slight improvement was that the black tones seemed blacker, if that makes any sense. This was noticed in the gap between the B ring and the planets disk especially although this did not seem to aid the detection of the C ring with the ED120 much. The additional aperture of the 150 offset the slightly more contrasty images that the ED120 was putting up perhaps ?. None of these large differences by any means though.

I will mention Mars briefly. I only had about 15 minutes observation time here at the end of last nights session. Mars was, at last, showing a little of it’s surface detail and the disk seemed large and crisp in both scopes at 250x. I could make out a small polar cap on the south pole of the planet and a larger pale area at the north pole. There were a few darker areas across the Martian disk but these still seem to be very insubstantial compared to how the planet can look when it’s relatively dust storm free. I’ll call it a draw on Mars !.

Moving onto the deeper sky targets, the differences here were pretty much what you might expect from a 25% aperture advantage. The bright galaxies showed respectable extension and form. M81’s dark rifts were a little better defined by the larger scope when the magnification was boosted to 100x. M31 and 32’s neighbour M110 was barely visible in either scope so the transparency during my sessions was not that good - not the scopes fault at all !

The double cluster in Perseus was a glorious sight in both refractors at low power. Very much “diamonds on velvet” with a number of faint reddish stars showing in amongst the groupings of jewels. Larger aperture refractors really show objects such as this superbly – you can get lost amongst the stars !

Lastly, for this initial performance report, I’ll turn to the planetary nebulae M57 (the Ring) and M27 (The Dumbbell). The Ring in Lyra showed it’s form very well. It was practically overhead and darkening of the central area contrasted very well with the seemingly twisted outer rim. The main difference between the two refractors on this object was that the magnitude 13 star just off to one side of the nebula stood out more clearly with the 150mm. Still visible with direct vision with the 120 but the aperture advantage can’t be denied with this. M27 was very well defined but, try as I might, I could not detect the central star with either scope.

So, after 5 hours observing with this sample of a Skywatcher Evostar ED150, what are my thoughts ?.

I think the ED150 is a really exciting scope but the example that I have been using is hampered by some sort of optical misalignment, likely the result of an impact in transit.

The colour correction of the scope seems really promising. I reckon it’s the equal of the ED120 which is high praise because that’s a very good scope optically. Skywatcher have got the glass combination right. What I really need is to try one where the star test is as it should be. If that can be achieved, and maintained, I feel the scope will a real winner at a very low retail price.

In every other respect Skywatcher have produced a worthy addition to the Evostar ED Pro range. The design is simple but very effective. The focuser does it’s job well. The scope is reasonably well balanced. The finish is attractive without being flashy. Heavier duty tube rings and dovetail bar are available at a reasonable cost if required but the stock items do their job effectively enough.

What Skywatcher do need to improve is the transit protection of the scope. More layers between the case and the outside world of rough handling. No thin straps to cut into cardboard. Sharp edges that can cause damage removed from the scope or covered for transit.

I’d love to try a Skywatcher ED150 Pro which has the objective lens working fully as it was intended by the optical designer. I’m really looking forward to that :grin:

 

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