How much visible difference between different quality optics is there?

[derekm]

The average SkyWatcher is about 1/4 to 1/4.5 PV, and a really exceptional one may reach nearly 1/5 PV. The OO ratings are given as better than so a 1/10 PV would usually be around 1/11 actual PV.

As to image comparison, if the seeing is good the SkyWatcher would be a bit better than image one and the OO about image 3. Although my 14" OO can give views similar to image 4 on really good nights. Don't forget that the OO Hilux coatings give better reflectivity which also has an effect.

The SkyWatcher newt optics are as good as it gets in a mass produced scope. I wouldn't hesitate to recommend one as you can't beat them for value for money. Unfortunately the closer you try to get to optical perfection the more rapidly the price increases.

John

Are your figures for the Skywatcher from actual tests you have carried out, or hearsay?

As far as "as good as it gets in a mass produced scope", see:

http://stargazerslounge.com/member-equipment-reviews/84376-revelation-12-dobsonian-4.html post 91

Don't underestimate the Chinese and Taiwanese in the 21st century; they can be an eye opener.

[John]

Are your figures for the Skywatcher from actual tests you have carried out, or hearsay?

As far as "as good as it gets in a mass produced scope", see:

http://stargazerslounge.com/member-equipment-reviews/84376-revelation-12-dobsonian-4.html post 91

Don't underestimate the Chinese and Taiwanese in the 21st century; they can be an eye opener.

There was a long thread on here a couple of years ago where an SGL member bought both an Orion Optics 8" F/4.5 and a Skywatcher 8" F/4.9 and tried them "back to back" as well as taking Orion Optics up on their offer the run the Skywatcher mirror through their Zygo tester. The results of the test were that the OO mirror was as specified (1/8th wave PV I think) and the Skywatcher came out around 1/6th wave PV if memory serves. Visually, I think our member could not tell any difference between the two scopes (he tried pretty hard over a period of time I recall) but kept the Orion Optics in the end I seem to recall, possibly because he had paid more for it.

[johninderby]

The PV for SkyWatcher mirrors I've quoted are based on a number of sources (some that I've spoken to directly) including those that have done laser infermoter tests, not mere hearsay, and they've all given very similar figures. Based on my own comparisons I'd have to agree with them.

And yes the Chinese manufacturers are capable of making better mirrors if the demand is there and customers are willing to pay for them. If someone like SkyWatcher would be willing to bring out a line of premium newts/dobs then I'm sure they could do so.

John

[RikM]

I think the message in this thread isn't that SkyWatcher Newts are poor, in fact far from it; for the price, they are very good indeed. But premium optics like those offered by OO, really are a bit better and it is down to the individual to decide if they feel the extra cost is justified.

I am very happy indeed with my SW Newtonians but when it's time to recoat my optics I will probably consider the Highlux coating. As well as a bit more brightness, the coatings also last longer.

[canuck]

In my opinion, an area where the quality of an optic is important (and can be noticed visually), is with splitting double stars. This exercise can involve very high magnifications when atmosphere allows. If the optic is not up to it, image breakdown can be quite obvious when the magnification is cranked up...

Just my two cents...

Richard

[ollypenrice]

These days many inexpensive telescopes are actually very good. Where expensive ones do tend to brain cheap ones is in the mechanical quality, which is darned important if your focuser sags and slips, your mirror won't hold collimation, etc etc.

Imaging is more exacting thanvisual observing, too. I was very happy with my Meade 127 visually and the current TEC is not all that different at the EP. The camera sees a much bigger difference though, most notably on the stars.

Olly