How good are they?

[mick pinner]

l have a question that l have been trying to work out for a while and thought l would pose it to the learned members: l recently spoke to Mark Schutting regarding the price of a mirror for a 10" newt of very good quality.
The price given was in my opinion reasonable for a good quality mirror but now the question, it was still twice the price of a complete 10" Bintel or Andrews dob so how do you conclude that the dob really is any good in comparison to anything else?
A friend of mine is wanting a scope so l'm looking at either buying or building one from scratch, is the dob really only any good because it is cheap?, how many people have a chance to look through high quality scopes and can therefore comment on how good the current dobs really are.

[davidpretorius]

maybe kens 12" dob vs bird new 13" mirror, is the only thing i can think of????

try next weekend??

[wavelandscott (Scott)]

Mick,

You are asking a very good question...

I have two reflectors...an 8 inch GSO (Bintel) and a 12.5 inch Discovery.

My personal thought is that most people most of the time won't see much difference...assuming it is a "good" example of the GSO mirror (there are some variances I've heard of)

I mean that there are other factors that will likely influence performance more critically that are within the users control that unless they have the skill and experience they will never get to take adantage of the high end mirror...

I'm probably a good example...I get my colimation "close", I get my scope "nearly" ambient, I stroll ini and out of the house while I am viewing getting "almost" light adapted...etc.

Yes, I prefer looking through the Discovery... I think it "looks" better...is it the mirror quality, the mirror size, the position of the eyepiece, vanity??? Probably a bit of it all...but I have found nothing wrong with the GSO scope...

Mechanically, I much prefer the Discovery but in terms of optics viewing from my backyard (remember I'm really a pretty inexperienced observer) other than size, I don't think there is a wide difference between them really...

Assuming that the performance of the GSO is 95% as good (pick a number) and my limited skill/experience the extra money for a high end mirror could probably be better spent...I liken this to buying a primary school band violinist a Stradivarious (spelling)...yes, they can play it but not push it to it's potential...

So, my advice (combined with $5 will get you a fine cup of coffee)...

Unless you are looking for someone who is or will become a highly proficient, capable and consistant observor, I'd save the money...the GSO scopes that I have used and seen are very good values for the money...

[Dave47tuc (David)]

Mick,
A friend of mine Russell T. Has one of Marks mirrors.
A 10" F6.3 I think. Its just over F6 anyway's.
I have looked through so many scopes its not funny.
But this scope is as good a scope or mirror that I have seen.

Without going into a lot of detail. We have observed Saturn in good seeing at 500x I can't describe how good it was.
We have observed the Moon also at 1450x I'm not kidding.
No image break down at all. Clear sharp view.
gts055 (Mark) will back me up on that.

Now if this mirror is one off I don't know.
But it gives a good as it gets star test.

I had a GSO 10" great scope for the price.
But it was not upto Russell's scope.
So yes I think Marks mirrors are worth it. IMO.

[Starkler (Geoff)]

To put things in perspective, I have yet to look through a sct that matches my gso dob for sharpness and contrast. Properly set up the cheap dobs are good, its a matter of how much you are willing to pay to get that bit closer to perfection.

[beren]

I have yet to look through a sct that matches my gso dob for sharpness and contrast

....you couldn't resist

Top reply Scott I share your thoughts as well good luck Mick with the decision

[Starkler (Geoff)]

Originally Posted by beren

....you couldn't resist

Just trying to be helpful and I know that Mick owns an sct.
If anyones experience is to the contrary I'm happy to listen.

[mickoking]

I own a 300 mm GSO Dob and its optics are fantastic. I have also owned a 350mm Dob with a hand figured mirror and it's optics were also fantastic. I know what I said may not help but the IMHO the GSO optics are very good, the hand figured optics are probably even better but I guess It comes down to personal prefrence and cost?

[mick pinner]

l knew someone would come to the defense of the dob, thank you for not dissapointing Geoff, l have no opinion one way or the other regarding dob optics or their performance against SCT's, l have only ever looked through two dobs those being Geoff's and Dave 47's.
l have never done a comparison and it would probably be of no value anyway considering the different nature of each scope ( dob v Sct ), it just seemed to me that with the price of a well finished mirror being twice the price of a complete dob in reality how good could the optics in a mass produced scope really be.

[janoskiss (Steve H)]

Mick, I recall that you did have a 10" Skywatcher Newt, and I believe you mentioned that the optics are on a par with those in GS Dobs. So I guess you have a fair idea of what the mass produced Dobs are like.

At the other end of the equation, if you come along to Snake Valley I'm sure Bird will let you have a peek through his 13" (mirror by Mark Suchting). We can check out some 12" Dobbies too (Ken, Wombat) at SV, to gauge what difference the aperture makes.

[mick pinner]

l did Steve but never used it enough to really evaluate it properly and it was to long ago to remember compared to my LX200 however after speaking to someone that had a GS mirror and a Skywatcher mirror tested at Siding Springs observatory there seems to be quite the quality difference leaning towards the Skywatcher mirror, may have just been those two mirrors l don't know but l will be interested in the views through a quality newt.