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Advice needed on Sumerian Alkaid options

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#1 BGazing

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Posted 12 September 2019 - 01:38 PM

I've read many good things about Sumerian scopes (especially the latest generations). There were some hiccups but they appear to have been sorted out and the production is reduced and streamlined. TS takes European orders and imposes uniform mirror choices. TS is not fun to deal with, slow to answer and the answers are terse and sometimes cryptic. Michael (who makes the scopes) does not appear to answer the mails (at least not yet to me) so I am left with the collective wisdom of the forum to pry some more information.

 

I understand that the 12 inch case weighs somewhere around 14kgs and the rest are truss poles. I'd be grateful if anyone comes up with the exact figure. Total weight is 16.5 as per both websites.

 

F RATIO AND BALANCE - Most reviews suggest that 10 inches version are bottom light and that they are not suitable for heavier eyepieces, and I presume Paracorr. 12 inches should have a better balance due to heavier mirror. Going F4 would make it more stable, sticking to F5 would make it easier to collimate, be easier on the EPs and (who knows) dissuade me from buying a Paracorr...straight away. I do notice coma at F5...

 

QUARTZ or PYREX - TS streamlined mirror offers to GSO Pyrex and TS branded quartz mirrors. At F5, both are available, at F4, only Pyrex. Quartz glass adds about 400eur to the bill, but the mirror seems to be 39mm thick just like Pyrex, presumably to avoid astigmatism because of the design of the cell. Lighter mirror would also be problematic because of the balance. So Quartz or not? There are fans behind, hopefully helping the cooldown and dealing with the boundary layer. Pyrex is slower to cool, but how much does that matter when you have the fans? Does Quartz offer much benefit when they are of the same thickness? GSO is Pyrex, Quartz is TS branded, anyone had any experience comparing them? 

 

So here are the options:

F5 and Quartz - more expensive, faster cooldown, easier on the EPs (although mine are all TV in 7-24mm range). Might still itch for Paracorr on top of it, adding to the bill. I know I will, sigh. Less stable than F4 balance-wise, although T6 plus Paracorr is almost like an Ethos.

F4 - more stable, more demanding on EPs, Paracorr a must (there goes the balance advantage, although still less strain than F5 with Paracorr). Pyrex only, slower cooldown.

F5 in Pyrex, easier on EPs than F4, easier collimation, slower cooldown, again Paracorr dilemma. Price pretty much the same like F4 Pyrex.

EQ Platform or not? Sumerian platforms are listed at 2 kgs weight...I find that hard to believe.

What are your thought and suggestions? 



#2 sg6

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Posted 12 September 2019 - 02:17 PM

Michael has been fairly good at replies in the past - somewhat distant past I admit.

 

He used to state that all orders were throuhgh TS, then one or two of the bigger ones were direct. Also you had to option of supplying your own mirror. He had a problem with mirrors and it caused problems for him.

 

Cannot see exactly what the situation is at present, reads as if he is doing it all - build and sale - but not stated specifically. It just states that TS are a Dealer, not the only source.

 

I see that only TS/GSO mirrors are specified, as said used to be other options, like supply your own eg Orion Optics UK.

 

It may be that he is on vacation, or email has got lost as in sent to spam.

 

Suggest you try again, it is about all.

 

Hate to divert business from Michael but do The Dobsonian Factory match the/your requirements?

Dobsonian-Factory



#3 BGazing

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Posted 12 September 2019 - 02:52 PM

Michael has been fairly good at replies in the past - somewhat distant past I admit.

 

He used to state that all orders were throuhgh TS, then one or two of the bigger ones were direct. Also you had to option of supplying your own mirror. He had a problem with mirrors and it caused problems for him.

 

Cannot see exactly what the situation is at present, reads as if he is doing it all - build and sale - but not stated specifically. It just states that TS are a Dealer, not the only source.

 

I see that only TS/GSO mirrors are specified, as said used to be other options, like supply your own eg Orion Optics UK.

 

It may be that he is on vacation, or email has got lost as in sent to spam.

 

Suggest you try again, it is about all.

 

Hate to divert business from Michael but do The Dobsonian Factory match the/your requirements?

Dobsonian-Factory

His website says that TS is the only dealer for Europe sans Benelux, so their mirror options are mandatory.

Dob Factory looks droolworthy, but too expensive, frankly and with iffy lead times. I've considered it but Sumerian looked like a 'reasonable' option and less hassle.


Edited by BGazing, 12 September 2019 - 02:52 PM.


#4 AlbertoJ

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Posted 12 September 2019 - 06:03 PM

 What are your thought and suggestions? 

Hello BGazing,

 

My thought is that you look for another dobson maker, as I did when I saw that Sumerian didn't reply my email I send at 8 July. 

A hand make dobson isn't a mass produced one, nor its price.

A hand maker dobson who isn't there to contact him, not even to answer something decisive for someone who is going to buy him a telescope, not worth it.

At least I think that, and I did accordingly.



#5 BGazing

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Posted 13 September 2019 - 01:30 AM

Hello BGazing,

 

My thought is that you look for another dobson maker, as I did when I saw that Sumerian didn't reply my email I send at 8 July. 

A hand make dobson isn't a mass produced one, nor its price.

A hand maker dobson who isn't there to contact him, not even to answer something decisive for someone who is going to buy him a telescope, not worth it.

At least I think that, and I did accordingly.

Feel free to suggest the alternative.

By the way, if you have used contact form to contact him, it apparently does not work, email only.



#6 AlbertoJ

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Posted 13 September 2019 - 04:11 AM

Yes, I send him an email.

Sumerian can be a good option for you, being 10-12 ", if you don't mind buying without contacting the manufacturer.
But for me it is essential that the manufacturer answers my requests, questions and possible problems that arise, especially in big dobsons.

 

I can not suggest or recommend anything that I have not tried, especially in ultra-compact dobson. Many of them are not stable or maintain the collimation of the mirror by moving them from the zenith to the horizon.

Perhaps in 12", there's no problem, but could be in 16"+

 

Premium classic or hybrid dobson (most from USA) are an optical, mechanical and operational guarantee, but at high prices. 

Now, I'm more interested in hybrid dobson, ATM, DIY.


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#7 sg6

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Posted 13 September 2019 - 05:11 AM

Will admit that the situation with Sumarian seems messy.

Not sure why TS as to be honest if I was looking for one TS is not who I would go through, it is not their area.

I know Michael did make them all, then had problems, then went through/with TS, then still advertised as making some himself direct. - the bigger ones as I recall. As mentioned that kept the option of your own mirror or choice of mirrors.

 

Some people may have a mirror from an older scope or want say an OOUK at f/4.7, some may have a Zambuto lying around waiting for a new home, which in the standard TS line is not catered for.

 

The oddity is his website does not state TS only, just that they are a dealer. So a little ambiguous maybe. His site has prices on and that usually implies purchase from there.

 

Not sure who else makes similar, other then DF. Expect there are a few, finding one could be the problem. Build your own?

 

Little point in asking at a carpentry company as the knowledge of scope construction/detail is a requirement. And that is likely a bit lacking.



#8 BGazing

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Posted 13 September 2019 - 06:45 AM

Well, going TS for him makes sense. No hassle with custom optics and custom requests, streamlining production and easier production runs. Customer care offloaded, you concentrate on what you do. TS is a monopoly de facto and centrally based in Europe, logistically at the best spot probably to move the goods cheaply by land. Their main competitor, FLO, is drifting away on the Brexit waves and is likely to be on the wrong side of the customs for the EU market very soon...for us outside the EU it's the same.

Anyway, my questions remain and I would be grateful for any suggestions, especially re mirror options.



#9 Riccardo_italy

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Posted 13 September 2019 - 09:22 AM

In the website it is stated that the Contact Form is not working. My best guess is that they have email problems right now.

Just send again the email....



#10 starzonesteve

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Posted 13 September 2019 - 09:32 AM

I am not an optician so please take this with a grain of salt...

 

First, quartz vs Pyrex. My understanding is that this is somewhat dependent on circumstances. If you are someplace where nighttime temperature drops are precipitous, quartz may be more beneficial. If you like to haul your scope out and start observing quickly (especially if your sessions are shorter), again quartz might get the nod. Although the advantage of Quartz might be partially mitigated by the relatively thicker mirror, the quartz will still be more stable than the Pyrex. On the other hand, depending on where your scope’s resting environment is, how long you have to let it acclimate to it’s observing environs, and how fastidious you are about using fans, there may be very little advantage gained by using quartz.

 

As to F4 or F5, all things being equal with a 12” scope I would probably go F5, but that is just me. I like a scope that will be fairly close to my eye’s standing height at zenith. With a 12” F5 on a platform you are probably approaching a very workable height. And then there are the less critical collimation/paracorr issues you mentioned. As to balance, that just depends on the particulars of the scope build and the eyepieces you expect to use.

 

You are right to explore these issues carefully before you commit. Buyer’s remorse can cloud your vision every bit as much as light pollution.wink.gif


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#11 BGazing

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Posted 13 September 2019 - 04:14 PM

This would be a dark site scope for those times where there are no planets to observe, so no tracking or ADC for low objects. Our regular dark site is often subject to rapid temp drops and sometimes to high humidity (although it is 1000m above sea level). In my C8 I can keep with the temp drops when I put in Lymax during the breaks and rest, but when the temp drops and the humidity creeps in Lymax is a no-go. I understand that newts handle such conditions better. Pyrex, I understand, might show more astigmatism while cooling...and the cooling might list very long.



#12 25585

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Posted 13 September 2019 - 06:00 PM

https://www.sumerianoptics.com/Prices

 

I think someone on Stargazerslounge has or had a Sumerian https://stargazerslo...rch/?q=sumerian



#13 Shneor

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Posted 13 September 2019 - 06:15 PM

I have a 10" Sumerian. It's compact enough for carryon baggage. I comes with elastic bands to allow the use of heavier eyepieces (like a 13 Ethos). But watch out if you want to change eyepieces! It is a very clever design and just about works. I have successfully used it at a public viewing event and just to look at planets in the street in front of my house (car lights, ambient light, etc.). It is usable but a bit finicky. Also, if you are using the platform, watch out when you use the elastic bands, you can uninterntionally separate the top and bottom of the platform.



#14 starzonesteve

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Posted 13 September 2019 - 06:41 PM

This would be a dark site scope for those times where there are no planets to observe, so no tracking or ADC for low objects. Our regular dark site is often subject to rapid temp drops and sometimes to high humidity (although it is 1000m above sea level). In my C8 I can keep with the temp drops when I put in Lymax during the breaks and rest, but when the temp drops and the humidity creeps in Lymax is a no-go. I understand that newts handle such conditions better. Pyrex, I understand, might show more astigmatism while cooling...and the cooling might list very long.

I know that quartz has a significantly lower thermal expansion than Pyrex, but it would be good to have a more experienced observer weigh in on how great that difference might be in the field given your particular circumstances.



#15 BGazing

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Posted 13 September 2019 - 11:54 PM

I have a 10" Sumerian. It's compact enough for carryon baggage. I comes with elastic bands to allow the use of heavier eyepieces (like a 13 Ethos). But watch out if you want to change eyepieces! It is a very clever design and just about works. I have successfully used it at a public viewing event and just to look at planets in the street in front of my house (car lights, ambient light, etc.). It is usable but a bit finicky. Also, if you are using the platform, watch out when you use the elastic bands, you can uninterntionally separate the top and bottom of the platform.

Thank you, very informative. I plan to use with T6 Nags, so I guess swapping them won't send the nose fluying...



#16 25585

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Posted 14 September 2019 - 01:51 AM

I have a 10" Sumerian. It's compact enough for carryon baggage. I comes with elastic bands to allow the use of heavier eyepieces (like a 13 Ethos). But watch out if you want to change eyepieces! It is a very clever design and just about works. I have successfully used it at a public viewing event and just to look at planets in the street in front of my house (car lights, ambient light, etc.). It is usable but a bit finicky. Also, if you are using the platform, watch out when you use the elastic bands, you can uninterntionally separate the top and bottom of the platform.

Sounds a bit McGyver to me!



#17 L.Roulin

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Posted 14 September 2019 - 09:15 AM

Hello,

 

I also own a 10" Alkaid. I've been using it with a 27 mm Pan, a 14 mm, a 5 mm and a 3,5 mm Pentax XWs. Their weights are approximatively the same. I can set the tension cords so the scope stays put when changing eyepieces.

 

Also don't underestimate the caveats the design comes with; it is nowhere near as stable as a traditional dobsonian and you may have to check the collimation more frequently, especially if you're going for targets that are far apart in the sky. Moreover, I bought the equatorial platform from Sumerian Optics, which further reduces the stability of the ensemble.

 

Nowadays I prefer using my 12.5" Obsession, or my 4" refractor when I want to travel light.

 

As Shneor said, "it is usable but a bit finicky".


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#18 sixela

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Posted 14 September 2019 - 06:07 PM

Michael sometimes answers mails, but often not when he has too many orders through TS. And yes, his "standard" Dobs are the bulk of his production now (he does make some "specials" for the people on the Dutch forum that supported him when he started and 'friends' -- and his contract with TS allows for that for Benelux orders --, but it's become financially nonviable for him to spend a lot of time on these).

 

As for Quartz vs. Pyrex -- forget about thermal characteristics, as the difference is negligible, but for the few ones I saw, the quartz mirrors were a lot smoother and generally better. It wouldn't surprise me if the source were not actually the same (my guess is that GSO's 500mm fused silica mirror is also not ultimately from the same source as their smaller mirrors, and perhaps from the same source as the TS Optics quartz mirrors).

 

You can also get an "independent" certificate from Wolfgang Rohr for these too (for a fee). He doesn't use the most modern data processing methods and frankly I don't like his methods to "qualitatively" judge 'stig and then test with 'stig removed to avoid some work, and of course given the volume of work TS provides him you can even question how "independent" he is, but at least if you pay extra the mirror does get tested and if even TS thinks it stinks they're going to send it back instead of plonking it into your scope (even though from experience for particularly egregious bad performance of the BK7-like mirrors TS accepts returns without too much fuss).

 

And yes, the Alkaids are made to be maximally compact, and are not as sturdy as even Michael's other designs, but good luck in convincing him to build you a Canopus these days (sadly). Now if someone could convince TS to offer Canopus...sadly, that's not where the market is for these scopes.

 

One thing: if you need the tension cords for everything then you should probably balance the scope with counterweights instead. They behave a lot better when they're "almost neutral" without the tension cords. I've got some counterweights that I attach with 3M DualLock on mine that make it balanced perfectly with no eyepiece, and the tension cords are only used to make sure the scope stay put when you put very heavy eyepieces in (yeah, I'm a sucker for the 17mm Ethos, even in an Alkaid).

 

They are uniquely compact, though. I observe with someone who has a 16" Alkaid (with an excellent John Nichol mirror plus an Antares Optics secondary) and it's striking to see how little of the trunk is occupied by the scope if you compare it to my scope (even though I built that one and it's definitely not an Obsession and already fairly compact).

 

The platforms have become more robust over the years but still presuppose that you're going to put an Alkaid on top -- you sure could not put something like an equal sized Obsession on them, and certainly not what you could put on any Tom Osypowski platform (but then, those tend to weigh more than an Alkaid ;-) ).


Edited by sixela, 14 September 2019 - 06:29 PM.

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#19 sixela

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Posted 14 September 2019 - 06:25 PM

A hand make dobson isn't a mass produced one, nor its price.

If you call these "mass produced" then frankly you have to call Obsessions "mass produced" as well, and it's probably harder to convince Obsession to change a detail on the scope than it is to convince TS, let alone Michael (if you happen to know him).

 

When he sold Canopus, his attitude was that of a custom scope builder (and my personal Alkaid proto is as custom as they get, even though it doesn't have some of the later tweaks that made them better), but frankly, some customers have made it very hard for him to continue to build those. 



#20 BGazing

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Posted 15 September 2019 - 03:42 AM

Michael sometimes answers mails, but often not when he has too many orders through TS. And yes, his "standard" Dobs are the bulk of his production now (he does make some "specials" for the people on the Dutch forum that supported him when he started and 'friends' -- and his contract with TS allows for that for Benelux orders --, but it's become financially nonviable for him to spend a lot of time on these).

 

As for Quartz vs. Pyrex -- forget about thermal characteristics, as the difference is negligible, but for the few ones I saw, the quartz mirrors were a lot smoother and generally better. It wouldn't surprise me if the source were not actually the same (my guess is that GSO's 500mm fused silica mirror is also not ultimately from the same source as their smaller mirrors, and perhaps from the same source as the TS Optics quartz mirrors).

 

You can also get an "independent" certificate from Wolfgang Rohr for these too (for a fee). He doesn't use the most modern data processing methods and frankly I don't like his methods to "qualitatively" judge 'stig and then test with 'stig removed to avoid some work, and of course given the volume of work TS provides him you can even question how "independent" he is, but at least if you pay extra the mirror does get tested and if even TS thinks it stinks they're going to send it back instead of plonking it into your scope (even though from experience for particularly egregious bad performance of the BK7-like mirrors TS accepts returns without too much fuss).

 

And yes, the Alkaids are made to be maximally compact, and are not as sturdy as even Michael's other designs, but good luck in convincing him to build you a Canopus these days (sadly). Now if someone could convince TS to offer Canopus...sadly, that's not where the market is for these scopes.

 

One thing: if you need the tension cords for everything then you should probably balance the scope with counterweights instead. They behave a lot better when they're "almost neutral" without the tension cords. I've got some counterweights that I attach with 3M DualLock on mine that make it balanced perfectly with no eyepiece, and the tension cords are only used to make sure the scope stay put when you put very heavy eyepieces in (yeah, I'm a sucker for the 17mm Ethos, even in an Alkaid).

 

They are uniquely compact, though. I observe with someone who has a 16" Alkaid (with an excellent John Nichol mirror plus an Antares Optics secondary) and it's striking to see how little of the trunk is occupied by the scope if you compare it to my scope (even though I built that one and it's definitely not an Obsession and already fairly compact).

 

The platforms have become more robust over the years but still presuppose that you're going to put an Alkaid on top -- you sure could not put something like an equal sized Obsession on them, and certainly not what you could put on any Tom Osypowski platform (but then, those tend to weigh more than an Alkaid ;-) ).

Well, that sounds interesting. Velcroing a small counterweight should not be that much of a problem, and there are always cords to the rescue. 17mm Ethos is a beast, though:). It's one kg, isn't it? How much weight do you need to lock behind to balance? You are not using it with Paracorr, I presume?

As for mirrors, smoothness is always good. I know Quartz is also supposed to show less astigmatism while cooling, but presumably better figure is more important. Those tests though, yeah, I will rather test it somewhere else (e.g. Tel Austria). 



#21 sixela

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Posted 15 September 2019 - 06:08 PM

My 10" Alkaid is a bit of a special beast -- it's got a very light Orion Optics mirror (refigured by Huygens Optical) and has two lead counterweights Michael made that are removable -- all to get it under 9kg for air travel. I usually need about 750g attached to the mirror box extra to balance a 17mm Ethos.

 

And yes, I've only tried a Paracorr once (with a different set of trusses). Too much hassle on that scope, but if it were an f/4 I'd probably have a different view.

 

As for the tests, I agree that Wolfgang Rohr cannot be thought of as really independent, but the aim is to have TS test it before they ship it to you, to avoid the hassle of getting a lemon and then having to ship it back.


Edited by sixela, 15 September 2019 - 06:13 PM.


#22 BGazing

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Posted 16 September 2019 - 12:07 AM

Understood.

Well, that handle on the mirror box looks good for velcroing a counterweight, and Celestron Lifepo powertank fits the bill. Something has to power that mirror fan anyway. :)



#23 AlbertoJ

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Posted 17 September 2019 - 05:02 PM

If you call these "mass produced" then frankly you have to call Obsessions "mass produced" as well, and it's probably harder to convince Obsession to change a detail on the scope than it is to convince TS, let alone Michael (if you happen to know him).

 

When he sold Canopus, his attitude was that of a custom scope builder (and my personal Alkaid proto is as custom as they get, even though it doesn't have some of the later tweaks that made them better), but frankly, some customers have made it very hard for him to continue to build those. 

Hello sixela,

You haven't understood me. I have call "hand made" to Sumerian, to differentiate it from mass produced dobsons, mostly chinese telescopes.

And as hand made dobson, I said a buyer has as minimum can contact with its maker, like happens with any hand made dobson.

 

Nevertheless, if I have to resolve all my doubts and make all my questions in a forum, due to the lack of the maker reply, I'd search for another hand dobson maker, or for the same customer service, I'd buy a mass produced dobson, like Meade,  Skywatcher, ... 


Edited by AlbertoJ, 17 September 2019 - 05:04 PM.


#24 sixela

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Posted 18 September 2019 - 02:07 AM

The customer service is not the only thing differentiating a mass produced scope from a handmade one ;-).

#25 AlbertoJ

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Posted 18 September 2019 - 04:59 AM

The customer service is not the only thing differentiating a mass produced scope from a handmade one ;-).

Exactly, also the stability of the structure and the optics. And in this, Sumerian is like a chinese mass produced dobson with its light and less stable structure and GSO chinese optics.

Only plywood work quality and its price is the difference. But customer service, performance and optics is like a mass produced one.




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