Orion Optics v Skywatcher!

[philsail1]

Yes, I think I agree with you there Rus!

Unless I am happily proved wrong with the next test of the Orion "Hi-lux" coatings and superior finished to the main mirror, I will end up thinking that manufacturers sometimes use "baffling" statistics to simply sell their scopes!

Although, I've heard that many observers do genuinely say that "Celestron's" special mirror coatings do make a real and positive difference to the views between scopes, with and without the coatings.

I would agree, that you are correct in saying that a 1/4 wave mirror is perfectly good enough for all but the most scientifically discerning of observers.

(I wonder to what degree the main mirror on "Hubble" is finished to?).

Regards,

philsail1

[brympton]

Oh! and they have also asked me to take in the main mirror from my Skywatcher 200mm and they will put it on the "Zygo" test rig and give me a PV wave report on it!

So, I'll take them up on the offer and let you all know what the PV wave is on a standard Skywatcher 200mm main mirror!

Now that will be interesting. Nice to see more evidence of improved customer service, hope all goes well for you

Regards

Mark

[philsail1]

Thanks Mark!

philsail1

[nitram100]

ooo can't wait to see the Zygo results on the Skywatcher!

[FLO]

So, I'll take them up on the offer and let you all know what the PV wave is on a standard Skywatcher 200mm main mirror!

ooo can't wait to see the Zygo results on the Skywatcher!

................. are we being serious? :scratch:

[GazOC]

"A few years ago optical gurus Terry Dickinson, Peter Ceravolo, and Doug George conducted an experiment in which Ceravolo made a set of 6" f/8 Newtonians, identical except for the wavefront error of their mirrors. Many observers were invited to try these, and were consistently able to spot the ones made to ½ wave or poorer, but only very experienced observers could detect the subtle differences between ¼ wave and 1/10 wave. Their conclusion was that most amateurs would be perfectly happy with the views from any scope that was an honest ¼ wavefront or better."

I've read that before and until earlier this year wasn't convinced. But having now owned the high quality 6" mirror and the standard 1/4wave job, i can safely say i couldn't really see any difference. That could well be because the observer is an idiot of course. But i would never go out of my way again to get that quality mirror. An honest 1/4 wave sounds good to me.

Russ

I used to have the full article but seem to have lost it, the upshot was that even when people could separate the better mirrors it was only on a very small number of objects (mainly planets IIRC).

[John]

ooo can't wait to see the Zygo results on the Skywatcher!

I think we can guess what they will show

Cynical me !

John

[Astronut]

...

(I wonder to what degree the main mirror on "Hubble" is finished to?).

According to Wikipedia:

"Although it was probably the most precisely figured mirror ever made, with variations from the prescribed curve of no more than 1/65 of the wavelength of visible light, it was too flat at the edges. The mirror was barely 2.3 micrometres out from the required shape, but the difference was catastrophic, introducing severe spherical aberration."

http://en.wikipedia.org/wiki/Hubble_Space_Telescope#Flawed_mirror

Embarrassing mistake for the contracted optics company to say the least.

[ngc2403]

hey,

Gaz, i thought that the mirrors are better tested by imaging through them, seen as cameras are much more accurate than the eye?

would images taken through to identical telescopes one with 1/4 and one 1/8 not have a noticable difference?

ooo can't wait to see the Zygo results on the Skywatcher!

me too i agree with Brympton this will be interesting

?

So, I'll take them up on the offer and let you all know what the PV wave is on a standard Skywatcher 200mm main mirror!

ooo can't wait to see the Zygo results on the Skywatcher!

................. are we being serious? :scratch:

? i don't know what you mean here steve ?

Philsail1,

don't get two screws on opposite sides of the focusser they don't work. Get three one on each side and one on the top

i got three and it is solid no fall out danger

ally

[GazOC]

I'm no imager Ally, I just look at stuff...

[ngc2403]

ah fair enough

well i hope the clouds clear soon

[brympton]

................. are we being serious? :scratch:

? i don't know what you mean here steve ?

No, I'm not sure about that either ally :? , do you think it is a fruitless exercise Steve...proof of the pudding and all that? It's a question I have asked before:

http://stargazerslounge.com/index.php/topic,31174.0.html

I presume Phil will be present during the test and given his "unbiased" review will be happy to accept his findings.

[orion f6.3]

Is this test based on a single or at the most a couple of nights testing? What about the temperature? one mirror will be fine at one and the other at another. Seeing conditions? and one big factor, you cant always use the same eyepiece in one scope and expect it to proform in another. I have had both the 10" version of the OO and skywatcher. The skywatcher is a great scope cooling in an hour or so, the OO takes 2 1/2 hrs to cool but blows the skywatcher away on EVERY single target.

[orion f6.3]

I've read that before and until earlier this year wasn't convinced. But having now owned the high quality 6" mirror and the standard 1/4wave job, i can safely say i couldn't really see any difference. That could well be because the observer is an idiot of course. But i would never go out of my way again to get that quality mirror. An honest 1/4 wave sounds good to me. Russ

Is this not the same as the "new" driver being given an old car, loving it, thinking it was great but slowly growing out of the love affair realising a newer better car will also get them from A to B only better? And if funds permit, why get a less quality mirror in which you will detect flaws in years to come when a high quality mirror will give years (or a lifetime) of service.

[GazOC]

An experienced astronomer has had the high end mirror and can't detect the any improvement over the cheaper standard mirror he has now. Whats the point in him paying extra for the expensive mirror? And, more importantly, why are car and scope analogies so puzzlingly popular?

[philsail1]

Well, I'm taking my Skywatcher mirror up to Orion Optics on Thursday of next week. (Along with the Orion Scope - to get the focuser exchanged for the "upgraded" version with "compression ring" eyepiece lock), so as soon as I receive results of the mirror test I'll post on here!

Yes, the "car" and "telescope" analogies do seem to be popular. I've been told (daren't mention any names!) that using the Orion scope under light poluted skies, is like trying to get the best out of a Bugatti "Veryon" by driving it along a counrty lane - as opposed to using the Orion on a crisp, clear night is akin to the Veryon's performance on a race track!

I'll be more than happy if, when comparing the Orion with the Skywatcher under optimum "seeing" conditions, I can actually detect a worthwhile improvement in the Orion's view. If I cannot, then I will have to agree with those who say that a basic (1/4 wave) mirror delivers a more than adequate optical performance for most people. (and manufacturers of more "perfectly" formed and finished mirrors just quote statistics to sell their scopes to people like me - who are unaware that improved mirrors can only be compared using sophisticated test equipement!).

At the end of the day, I think that even if the Orion does not produce a significantly better view than the Skywatcher, it will still be an excellent scope, and if anyone had bought one as a first scope (with nothing to compare it to), they would be more than pleased - once the focuser issue had been resolved of course! Let's face it, is there such a thing as the perfect scope - one of the first things we do to our Skywatcher scopes, is change the focuser to a better one! I think even the most expensive scopes do have some shortcomings, and perhaps people there are a few people who have even experienced "some" slight disappointment with some aspect of their £1,000 + scope purchase.

All I want to achieve out of my testing and comparing, is a positive enough result to enable me decide which scope I will sell on! (I've only got one pair of eyes, so I just don't see the point in keeping 4 scopes on the go!).

What I want to do is just keep one scope for wide field views (and some basic photography), and one scope for views of the planets - but this is for another future thread!

Thanks to everyone for your interest!

Regards,

philsail1

[FLO]

... do you think it is a fruitless exercise Steve

No disrespect to OO, who are responsible for some very nice mirror sets, but the thought of them providing specifications for their no.1 competitor's product........ I feel sure Synta would prefer that it were someone more independent and objective.

Perhaps its just me

[GazOC]

Perhaps its just me

No, it registered on my "Cynic-o-meter" as well...;O)

[FLO]

Thats a relief, I thought I was going bonkers :shaking2:

[Whippy]

I have had both the 10" version of the OO and skywatcher. The skywatcher is a great scope cooling in an hour or so, the OO takes 2 1/2 hrs to cool but blows the skywatcher away on EVERY single target.

But if you let the SW scope cool down for 2 1/2 hours would the OO scope still be vastly better? No offence, but I'm sceptical. I can appreciate that having a better mirror set can give better views but 'blow it out of the water'? I'm not so sure.

Tony..

[philsail1]

I think Barry (from Orion) will give the Skywatcher an honest test - because he knows the Skywatcher mirrors are mass produced, and with me telling him that the views between the Orion and Skywatcher were almost identical (to me anyway!) I think he may have thought that the particular mirror on my Skywatcher had been (accidently) finished to a higher spec than normal. (I don't think it could be, but I suppose one never knows!).

I'll give him the benefit of the doubt anyway.

Regards,

philsail1

[GazOC]

Maybe Skywatcher had forgot to put the mirror through their final process which roughs up the mirror from 20/1th down to 1/4th wave just before they are shipped out?

[brympton]

Perhaps its just me

No, not at all, I agree that this is not ideal but in the absence of any independent testing and with Phil being present it is interesting. My guess is that the SW will be 1/4 or 1/6 wave which would then leave us with the "is it noticeable" argument. Phil has (IMHO) posted a very honest review and I hope to be able to do the same

[FLO]

Maybe Skywatcher had forgot to put the mirror through their final process which roughs up the mirror from 20/1th down to 1/4th wave just before they are shipped out?

You'd think with all their 'mass production' skills they'd remember a simple thing like that

[GazOC]

I agree Brymton, it would have been easy for Phil to subconciously will himself "see" a difference given the money spent.