10" open trust DOB is $649
https://www.amazon.com/10-inch-Hybrid-Truss-Dobsonian-Telescope/dp/B0B7SKSBPZ?ref_=ast_sto_dp

12" open trust DOB is $2000
https://www.amazon.com/Explore-Scientific-305mm-Truss-Dobsonian/dp/B01N0VDY1H?ref_=ast_sto_dp

So, the 12" DOB is 3x better than the 10" DOB?
Amazing?

On 30/09/2022 04:56, StarDust wrote:
> 10" open trust DOB is $649
> https://www.amazon.com/10-inch-Hybrid-Truss-Dobsonian-Telescope/dp/B0B7SKSBPZ?ref_=ast_sto_dp
>
> 12" open trust DOB is $2000
> https://www.amazon.com/Explore-Scientific-305mm-Truss-Dobsonian/dp/B01N0VDY1H?ref_=ast_sto_dp
>
> So, the 12" DOB is 3x better than the 10" DOB?
> Amazing?

Fair cost of a scope scales roughly as the materials cost needed to make
it work reliably which is roughly as the cube of the diameter.

So 1.73x AOBE for 10" to 12"

But you are deliberately making an unfair comparison between an old
design remaindered scope and a full price Mk II.
The corresponding 10" is the 1045-00 for $1090.

https://explorescientificusa.com/collections/dobsonians

In reality prices go up steeper than simple cost of materials theory
since fewer people buy really big scopes and high volume mass production
makes certain moderate sizes much more economical to manufacture.

Once you go beyond mass produced sizes there is a big step up in price.

--
Regards,
Martin Brown

On Friday, September 30, 2022 at 11:40:11 AM UTC-7, Martin Brown wrote:
> On 30/09/2022 04:56, StarDust wrote:
> > 10" open trust DOB is $649
> > https://www.amazon.com/10-inch-Hybrid-Truss-Dobsonian-Telescope/dp/B0B7SKSBPZ?ref_=ast_sto_dp
> >
> > 12" open trust DOB is $2000
> > https://www.amazon.com/Explore-Scientific-305mm-Truss-Dobsonian/dp/B01N0VDY1H?ref_=ast_sto_dp
> >
> > So, the 12" DOB is 3x better than the 10" DOB?
> > Amazing?
> Fair cost of a scope scales roughly as the materials cost needed to make
> it work reliably which is roughly as the cube of the diameter.
>
> So 1.73x AOBE for 10" to 12"
>
> But you are deliberately making an unfair comparison between an old
> design remaindered scope and a full price Mk II.
> The corresponding 10" is the 1045-00 for $1090.
>
> https://explorescientificusa.com/collections/dobsonians
>
> In reality prices go up steeper than simple cost of materials theory
> since fewer people buy really big scopes and high volume mass production
> makes certain moderate sizes much more economical to manufacture.
>
> Once you go beyond mass produced sizes there is a big step up in price.
>
> --
> Regards,
> Martin Brown

We're talking 2" difference in size, looks the same designed scope, except the 12"'s upper cage is different.
Don't see the 3x price justified, unless the mirror is some very high quality?
DOBs with high quality optics, like Star master etc... can sell for multiple price vs the run-of-the-mill Chines made DOBs of the same size.

On Friday, September 30, 2022 at 9:13:14 PM UTC-7, StarDust wrote:
> On Friday, September 30, 2022 at 11:40:11 AM UTC-7, Martin Brown wrote:
> > On 30/09/2022 04:56, StarDust wrote:
> > > 10" open trust DOB is $649
> > > https://www.amazon.com/10-inch-Hybrid-Truss-Dobsonian-Telescope/dp/B0B7SKSBPZ?ref_=ast_sto_dp
> > >
> > > 12" open trust DOB is $2000
> > > https://www.amazon.com/Explore-Scientific-305mm-Truss-Dobsonian/dp/B01N0VDY1H?ref_=ast_sto_dp
> > >
> > > So, the 12" DOB is 3x better than the 10" DOB?
> > > Amazing?
> > Fair cost of a scope scales roughly as the materials cost needed to make
> > it work reliably which is roughly as the cube of the diameter.
> >
> > So 1.73x AOBE for 10" to 12"
> >
> > But you are deliberately making an unfair comparison between an old
> > design remaindered scope and a full price Mk II.
> > The corresponding 10" is the 1045-00 for $1090.
> >
> > https://explorescientificusa.com/collections/dobsonians
> >
> > In reality prices go up steeper than simple cost of materials theory
> > since fewer people buy really big scopes and high volume mass production
> > makes certain moderate sizes much more economical to manufacture.
> >
> > Once you go beyond mass produced sizes there is a big step up in price.
> >
> > --
> > Regards,
> > Martin Brown
> We're talking 2" difference in size, looks the same designed scope, except the 12"'s upper cage is different.
> Don't see the 3x price justified, unless the mirror is some very high quality?
> DOBs with high quality optics, like Star master etc... can sell for multiple price vs the run-of-the-mill Chines made DOBs of the same size.

These Explorer-Sci DOB's are all made in China, only the SCTs and some of the refractors are made in the US, as I heard!

On Friday, September 30, 2022 at 9:13:14 PM UTC-7, StarDust wrote:

> We're talking 2" difference in size, looks the same designed scope, except the 12"'s upper cage is different.
> Don't see the 3x price justified, unless the mirror is some very high quality?
> DOBs with high quality optics, like Star master etc... can sell for multiple price vs the run-of-the-mill Chines made DOBs of the same size.

I don't know if you realize that the 12" has 1.44 times more surface area than does the 10". I know this does not seem to correlate directly with the price difference, but still, that extra area can make a difference when observing on the ragged edge.

On Friday, September 30, 2022 at 10:05:33 PM UTC-7, palsing wrote:
> On Friday, September 30, 2022 at 9:13:14 PM UTC-7, StarDust wrote:
> > We're talking 2" difference in size, looks the same designed scope, except the 12"'s upper cage is different.
> > Don't see the 3x price justified, unless the mirror is some very high quality?
> > DOBs with high quality optics, like Star master etc... can sell for multiple price vs the run-of-the-mill Chines made DOBs of the same size.
> I don't know if you realize that the 12" has 1.44 times more surface area than does the 10". I know this does not seem to correlate directly with the price difference, but still, that extra area can make a difference when observing on the ragged edge.

No shit!
Apertura AD12 Dobsonian 12" $1299
10" $949
https://www.highpointscientific.com/apertura-ad12-12inch-dobsonian-telescope-ad12?utm_source=google&utm_medium=cse&utm_term=APT-AD12&utm_source=google&utm_medium=cpc&utm_campaign=18147526044&utm_content=142198545324&utm_term=

On 01/10/2022 05:13, StarDust wrote:
> On Friday, September 30, 2022 at 11:40:11 AM UTC-7, Martin Brown wrote:
>> On 30/09/2022 04:56, StarDust wrote:
>>> 10" open trust DOB is $649
>>> https://www.amazon.com/10-inch-Hybrid-Truss-Dobsonian-Telescope/dp/B0B7SKSBPZ?ref_=ast_sto_dp
>>>
>>> 12" open trust DOB is $2000
>>> https://www.amazon.com/Explore-Scientific-305mm-Truss-Dobsonian/dp/B01N0VDY1H?ref_=ast_sto_dp
>>>
>>> So, the 12" DOB is 3x better than the 10" DOB?
>>> Amazing?
>> Fair cost of a scope scales roughly as the materials cost needed to make
>> it work reliably which is roughly as the cube of the diameter.
>>
>> So 1.73x AOBE for 10" to 12"
>>
>> But you are deliberately making an unfair comparison between an old
>> design remaindered scope and a full price Mk II.
>> The corresponding 10" is the 1045-00 for $1090.
>>
>> https://explorescientificusa.com/collections/dobsonians
>>
>> In reality prices go up steeper than simple cost of materials theory
>> since fewer people buy really big scopes and high volume mass production
>> makes certain moderate sizes much more economical to manufacture.
>>
>> Once you go beyond mass produced sizes there is a big step up in price.
>>
>> --
>> Regards,
>> Martin Brown
>
> We're talking 2" difference in size, looks the same designed scope, except the 12"'s upper cage is different.
> Don't see the 3x price justified, unless the mirror is some very high quality?

The difference is in the weight and the additional material needed to
support it. Scopes scale in cost like aperture^2.8 (D^3 is close
enough). The latest professional big kit scales as D^2.5 (after a lot of
very careful research to get the support structure costs down).

http://www2.lowell.edu/users/gerard/publications/van_belle_meinel2_2004.pdf

I reckon a 0.3m professional grade scope built using their pricing law
(Fig 1) would come in at about $100k. Good quality amateur grade scopes
are a bargain today they have remained around the £2k mark for many
years thanks to the rise of mass produced optics.

A lot of research has gone into making big telescopes so that they
deform gracefully under gravity but retain true parabolic shape when
tilted at any angle but with a minimum weight support structure. You can
extrapolate their graph back to amateur sizes to see what an observatory
class instrument would cost if built to their exacting standards.

Interestingly in the UK Explore Scientific lightweight Dobs are priced
somewhat differently to in the USA (bit of price gouging maybe):
Theoretical cost (approx)
10" £800 1x
12" £1200 1.5-1.7x
16" £2440 3-4x

It is unusual for anything high tech to be cheaper in the UK than US.

> DOBs with high quality optics, like Star master etc... can sell for multiple price vs the run-of-the-mill Chines made DOBs of the same size.

You will pay a lot more for lambda/20 truly diffraction limited
parabolised optics that you do for a lambda/4 (if that) light bucket.

--
Regards,
Martin Brown

On Thursday, September 29, 2022 at 11:56:59 PM UTC-4, StarDust wrote:
> 10" open trust DOB is $649
> https://www.amazon.com/10-inch-Hybrid-Truss-Dobsonian-Telescope/dp/B0B7SKSBPZ?ref_=ast_sto_dp
>
> 12" open trust DOB is $2000
> https://www.amazon.com/Explore-Scientific-305mm-Truss-Dobsonian/dp/B01N0VDY1H?ref_=ast_sto_dp
>
> So, the 12" DOB is 3x better than the 10" DOB?
> Amazing?

The prices for many things have risen so much that the markets are now distorted almost beyond recognition.

If you are asking this question because you can't decide which to buy, then just compare each model feature by feature to see if or why there should be such a price difference.

Maybe 12-inch mirrors are expensive to obtain these days...

This is probably not the greatest time to make such purchases anyway.

On Sunday, October 2, 2022 at 9:22:07 AM UTC-7, W wrote:
> On Thursday, September 29, 2022 at 11:56:59 PM UTC-4, StarDust wrote:
> > 10" open trust DOB is $649
> > https://www.amazon.com/10-inch-Hybrid-Truss-Dobsonian-Telescope/dp/B0B7SKSBPZ?ref_=ast_sto_dp
> >
> > 12" open trust DOB is $2000
> > https://www.amazon.com/Explore-Scientific-305mm-Truss-Dobsonian/dp/B01N0VDY1H?ref_=ast_sto_dp
> >
> > So, the 12" DOB is 3x better than the 10" DOB?
> > Amazing?
> The prices for many things have risen so much that the markets are now distorted almost beyond recognition.
>
> If you are asking this question because you can't decide which to buy, then just compare each model feature by feature to see if or why there should be such a price difference.
>
> Maybe 12-inch mirrors are expensive to obtain these days...
>
> This is probably not the greatest time to make such purchases anyway.

Apertura AD12 Dobsonian 12" $1299
This is a tube type DOB, much cheaper than the $2000 open trust 12"
So, can't be the mirror?
https://www.highpointscientific.com/apertura-ad12-12inch-dobsonian-telescope-ad12?utm_source=google&utm_medium=cse&utm_term=APT-AD12&utm_source=google&utm_medium=cpc&utm_campaign=18147526044&utm_content=142198545324&utm_term=

On 03/10/2022 05:14, StarDust wrote:
> On Sunday, October 2, 2022 at 9:22:07 AM UTC-7, W wrote:
>> On Thursday, September 29, 2022 at 11:56:59 PM UTC-4, StarDust wrote:
>>> 10" open trust DOB is $649
>>> https://www.amazon.com/10-inch-Hybrid-Truss-Dobsonian-Telescope/dp/B0B7SKSBPZ?ref_=ast_sto_dp
>>>
>>> 12" open trust DOB is $2000
>>> https://www.amazon.com/Explore-Scientific-305mm-Truss-Dobsonian/dp/B01N0VDY1H?ref_=ast_sto_dp
>>>
>>> So, the 12" DOB is 3x better than the 10" DOB?
>>> Amazing?
>> The prices for many things have risen so much that the markets are now distorted almost beyond recognition.
>>
>> If you are asking this question because you can't decide which to buy, then just compare each model feature by feature to see if or why there should be such a price difference.
>>
>> Maybe 12-inch mirrors are expensive to obtain these days...

It seems to be a US pricing anomaly. The UK prices are nearly in line
with theory (if anything the 12" Explore Scientific is a bargain here).
£1200 = $1300 thanks to the collapse of the GBP against USD.

Interestingly in the UK Explore Scientific lightweight Dobs are priced
somewhat differently to in the USA (bit of price gouging maybe):
Theoretical cost (approx)
10" £800 1x
12" £1200 1.5-1.7x
16" £2440 3-4x

It is unusual for UK prices to be lower than in the USA...

>> This is probably not the greatest time to make such purchases anyway.

It may soon be a great time to buy expensive high end kit from
distressed sellers who need to pay their mortgage.

> Apertura AD12 Dobsonian 12" $1299
> This is a tube type DOB, much cheaper than the $2000 open trust 12"
> So, can't be the mirror?
> https://www.highpointscientific.com/apertura-ad12-12inch-dobsonian-telescope-ad12?utm_source=google&utm_medium=cse&utm_term=APT-AD12&utm_source=google&utm_medium=cpc&utm_campaign=18147526044&utm_content=142198545324&utm_term=

Again you are not comparing like with like.

The optical quality figure and polish of a mirror is a very dominant
factor in its cost. Some big DOBs are notorious for being barely
lambda/4 light buckets often with a horrible turned down edge.

https://www.edmundoptics.com/f/lambda4-first-surface-mirrors/12274/

High end mirrors tend to be lambda/10 or lambda/20 with prices to match
the difficulty of their manufacture. It also depends a bit on the mirror
finish that is applied to it with gold being the most expensive:

https://www.edmundoptics.com/f/lambda20-first-surface-mirrors/15043/

--
Regards,
Martin Brown

On Monday, October 3, 2022 at 12:14:03 AM UTC-4, StarDust wrote:
> On Sunday, October 2, 2022 at 9:22:07 AM UTC-7, W wrote:
> > On Thursday, September 29, 2022 at 11:56:59 PM UTC-4, StarDust wrote:
> > > 10" open trust DOB is $649
> > > https://www.amazon.com/10-inch-Hybrid-Truss-Dobsonian-Telescope/dp/B0B7SKSBPZ?ref_=ast_sto_dp
> > >
> > > 12" open trust DOB is $2000
> > > https://www.amazon.com/Explore-Scientific-305mm-Truss-Dobsonian/dp/B01N0VDY1H?ref_=ast_sto_dp
> > >
> > > So, the 12" DOB is 3x better than the 10" DOB?
> > > Amazing?
> > The prices for many things have risen so much that the markets are now distorted almost beyond recognition.
> >
> > If you are asking this question because you can't decide which to buy, then just compare each model feature by feature to see if or why there should be such a price difference.
> >
> > Maybe 12-inch mirrors are expensive to obtain these days...
> >
> > This is probably not the greatest time to make such purchases anyway.
> Apertura AD12 Dobsonian 12" $1299
> This is a tube type DOB, much cheaper than the $2000 open trust 12"
> So, can't be the mirror?
> https://www.highpointscientific.com/apertura-ad12-12inch-dobsonian-telescope-ad12?utm_source=google&utm_medium=cse&utm_term=APT-AD12&utm_source=google&utm_medium=cpc&utm_campaign=18147526044&utm_content=142198545324&utm_term=

\\\

You keep comparing apples with oranges....

A tube-style Dob will be more difficult to store and transport. Some people will pay a premium for a telescope that can fit in the trunk.

The prices of the optics can vary widely depending mostly on quality.

The issue here is that the 10-inch in the original question is perhaps lower-priced than it can be. Or maybe the vendor has these things piled up in the warehouse, costing too much to store.

You need to do your homework.

On Monday, October 3, 2022 at 6:07:49 AM UTC-4, Martin Brown wrote:

> >> This is probably not the greatest time to make such purchases anyway.

> It may soon be a great time to buy expensive high end kit from
> distressed sellers who need to pay their mortgage.

The discussion about brand new telescopes, NOT used gear.

You are comparing apples with oranges.

Take your strawman arguments elsewhere. They are not welcome under my comments.