Dobs - Mass production optics vs premium optics

[Mark at Beaufort]

I once owned a Orion Optics 6" Newt with 1 /12th wave mirror and it was good. However, I now have a Skywatcher 150P which I use using high quality eyepiece and I am more than satisfied with the views. In addition I have a Revelation 12" Dob and I am again very satisfied with the view.

 My home was bortle 4 until recently and has now dropped to 5 with a reading of 20.30.

[Stu1smartcookie]

On 06/01/2022 at 12:32, Merlin said:

Most of us use our ‘scopes for stargazing rather than research. It seems to a case of overkill to have a premium grade ‘scope for casual viewing.

I think when we try to confuse the hobby of stargazing with someone that uses astronomy for anything more than a pastime the lines are inevitably drawn that a casual viewer by definition probably has less , shall we say , premium equipment ... but , dont we ALL have less premium equipment next to the Hubble and the JW scope ? Optics  are better these days and astronomy equipment is much cheaper allowing casual stargazers to invest in scopes that people of past era's would have loved to use . The other problem is the dreaded Light polution which can render the most premium scope basically useless , whereas a cheap achromat in a dark site can show the wonders of the night sky . Its all a bit of a minefield . 

 

[Guest]

53 minutes ago, mikeDnight said:

I think the gap between Premium and mass produced anything, be it refractors, reflectors or eyepieces,  has closed dramatically over the last 20years. A mass produced Dob with a top quality eyepiece will likely deliver better views than a premium Dob of the same aperture, that's using a mediocre eyepiece. The eyepiece after all is half the telescope. And there are many premium quality eyepieces to choose from, not just Televue.

There is truth to that.  There is no doubt that the mass produced scopes have gotten better.  The local astronomy club has several "vintage" scopes and there is no doubt that they newer scopes do a better job transmitting light .

[Andrew_B]

On 16/02/2022 at 03:30, jetstream said:

Depends on whether the mass produced optic is a " good one" - scatter (roughness) can be an issue in some. Many mass produced dobs benefit from stray light control -actually many high end structures do too. Controlling stray light in a dob is very high on my priority list.

But then, we pull out the Heritage 130 and observe so many DSO with this scope.... M33 a bright puff ball, M101, M51 The Flaming Star neb, California neb, Lagoon, Rossette, Barnards Loop and on and on.

I think this kind of points out the fact that dark skies are more important than the scope for DSO.IMHO.

I think I read a comment by Roland Christen that said figure and polish were everything for high magnification planetary observing and other aspects of the design were relatively unimportant, while for DSOs those qualities don't matter very much (so long as they're not terrible) and its light control through properly blackened and baffled tubes that makes the difference.

[Andrew_B]

On 16/02/2022 at 09:33, Mike Q said:

800x is a dream.  My skies in Ohio limit me to about 300x on the best of nights.  

Sounds like you don't have the skies that would let a premium Dob show its quality. The larger scope would obviously show more which would mainly be an advantage when viewing DSOs, but that would be the case whether its optics were inexpensive or high-end and it would be very high magnification viewing of the planets that you'd need to see the difference from having a premium mirror.

[Guest]

1 hour ago, Andrew_B said:

Sounds like you don't have the skies that would let a premium Dob show its quality. The larger scope would obviously show more which would mainly be an advantage when viewing DSOs, but that would be the case whether its optics were inexpensive or high-end and it would be very high magnification viewing of the planets that you'd need to see the difference from having a premium mirror.

Ohio skies suck.  You can have a clear night, but either seeing or the transparency will be terrible.  Even out in the boondocks  where I live we are a 4 on the Bortle scale.  In the last 6 months we have had 2 nights that have been really good.  

[catburglar]

The OP asked 3 questions:

Has anyone done a side by side comparison of standard vs premium sob at the same aperture? I haven’t, but I’m pretty sure I know the answers to the other two questions (I would say that wouldn’t I 😁)

Is the cost premium worth it in respect of optical performance? For some yes and for some no…It’s a personal value judgement that each of us would make…Those that have made it will most likely not regret having done so because in addition to any optical performance gain they’ve probably also got a scope with much improved mechanics that makes the ownership and observing experience much more enjoyable- what’s not to like about that?

Are the optical differences immediately obvious? Probably not ‘at first glance’ but I’d suggest it depends on a number of factors beyond the scope optics- object type, seeing conditions, light pollution and observer skill and experience. But I’m sure there will be differences most likely towards the threshold of visibility because the law of diminishing returns applies in optics manufacturing as well…so that’ll be subtle planetary features at high magnification or perhaps low contrast DSO’s…

So in practice I think this boils down to how much am I prepared to spend? If I’m prepared to spend on premium optics I’ll almost certainly be able to justify it to myself and if I’m not then I can be satisfied that I’m not missing out on too much…
 

I’d like to dip my toes in the water of the the former group, but I’m comfortable with being in the latter.

 

 

[davidc135]

When you spend the extra on better optics you know that you're not going to be unlucky and get this:

With plenty of astigmatism the mirror was hardly useable before re-figuring. It didn't come from China.  David

Edited February 18, 2022 by davidc135

[jetstream]

Clear dark skies and excellent seeing will bring out the differences in optics including eyepieces. IMHO.

[Louis D]

On 18/02/2022 at 04:25, Mike Q said:

Ohio skies suck.  You can have a clear night, but either seeing or the transparency will be terrible.  Even out in the boondocks  where I live we are a 4 on the Bortle scale.  In the last 6 months we have had 2 nights that have been really good.  

Sounds like you need to move to Texas.  Excellent seeing on many clear nights, and winter nights are mild.  That, and you don't have to deal with snow and ice very often, and cars never rust out due to road salt.  We really need more upper Midwesterners moving down here to balance out all of the Californians moving in.

As far as mass production Dobs vs custom Dobs, I really notice the difference in the motions and focusers.  Balance, smothness, and sticktion have been well thought out in custom Dobs and their focusers tend to be buttery smooth in use (Feather Touch, MoonLite, or similar).  I don't have the time to tinker with a scope to perfect it.  I'd rather pay someone local to the US or Europe to build it right from the start.  Does anyone espouse buying Chinese made cars over US, Japanese, and European cars, and then upgrading all the bits and pieces to make them road worthy?

[Guest]

8 hours ago, Louis D said:

Sounds like you need to move to Texas.  Excellent seeing on many clear nights, and winter nights are mild.  That, and you don't have to deal with snow and ice very often, and cars never rust out due to road salt.  We really need more upper Midwesterners moving down here to balance out all of the Californians moving in.

As far as mass production Dobs vs custom Dobs, I really notice the difference in the motions and focusers.  Balance, smothness, and sticktion have been well thought out in custom Dobs and their focusers tend to be buttery smooth in use (Feather Touch, MoonLite, or similar).  I don't have the time to tinker with a scope to perfect it.  I'd rather pay someone local to the US or Europe to build it right from the start.  Does anyone espouse buying Chinese made cars over US, Japanese, and European cars, and then upgrading all the bits and pieces to make them road worthy?

I have used a Teeter Dob, around a 20 inch, I was able to control it quite well from the get go.  With my Skyline there is a bit of trial and error getting everything set just right and even then the fact that it is so light it is easy to overshoot the target when you are giving it that little bump.

As to moving to Texas....well...it could happen....when you get rid of all the Rattlesnakes.   I hate snakes and the ones that can kill you with one bite....I especially hate those.

 

As to scope quality, well I wish I could afford an American made scope, but that was just not possible.  The Chinese have been making glass for 2000 years, while the mirror in mine is pretty good, you would think that by now they would have figured out how to make it better lol.  It is what it is I guess.

Edited February 21, 2022 by Guest

[Louis D]

2 hours ago, Mike Q said:

The Chinese have been making glass for 2000 years, while the mirror in mine is pretty good, you would think that by now they would have figured out how to make it better lol.

It is curious Chinese made ED and APO scopes usually use Ohara or Shott glass.  You'd think China would have mastered making optical glass by now.

[jetstream]

12 hours ago, Louis D said:

It is curious Chinese made ED and APO scopes usually use Ohara or Shott glass.  You'd think China would have mastered making optical glass by now.

Kinda makes me wonder why others (than China) use Ohara and Schott but charge so much more...

China, using this name brand glass sure adds marketability IMHO, even if they can make the equivalent, IMHO.

[Louis D]

32 minutes ago, jetstream said:

Kinda makes me wonder why others (than China) use Ohara and Schott but charge so much more...

Labor and overhead costs are very low in China compared to the US and Europe.

[Deadlake]

3 hours ago, Louis D said:

Labor and overhead costs are very low in China compared to the US and Europe.

I suspect it's the figuring that makes all the difference as is the ability to test optics performance.
Having someone who can figure the lens efficiently makes a big difference as constantly setting up the lenses for testing takes more time that you would think.

[Stu]

37 minutes ago, Deadlake said:

I suspect it's the figuring that makes all the difference as is the ability to test optics performance.
Having someone who can figure the lens efficiently makes a big difference as constantly setting up the lenses for testing takes more time that you would think.

Have you done much optics testing Martin? It’s an interesting area but I only know basic theory, nothing practical.

[Deadlake]

46 minutes ago, Stu said:

Have you done much optics testing Martin? It’s an interesting area but I only know basic theory, nothing practical.

Just long conversations with some dealers in why it’s not just a glasses properties that effect performance. The actual manufacturing process drives the end result. I’ll dig out the e-mails and share privately if you are interested.