Talk:Dobsonian telescope

message: This article seemed to incorrectly describes the "Dobsonian" as just a mount. The "Dobsonian" is actually an innovative telescope and mount design. I don’t know if this is because it was originaly a redirect from an article about mount types but I have edited it to be more descriptive of the entire class “Dobsonian”.(Halfblue 05:00, 10 March 2006 (UTC)
thread_title: Correction to article

message: Is there such a thing as a Dobsonian Mount? The Dobsonian seems to be a class of telescope that uses a combination of previously know innovations for a specific design purpose (a large, cheap, portable, deep sky instrument). It may be a misnomer to call any one of those design features "Dobsonian". i.e. The Dobsonians do not have "Dobsonian Mounts"; they have Altazimuth_mounts. And those Altazimuth_mounts may use John Dobson's design features but that would make them  "Dobsonian style" Altazimuth_mounts. I have made a few minor text changes to this end but would appreciate other people’s opinions.   Halfblue 05:16, 21 March 2006 (UTC)
replies: text: Well, there isn't really any such thing as a "Dobsonian telescope" - I was about to mention that here.  The telescope is a normal Newtonian.  The characteristic feature is the mount.  You're correct that it is an Alt-Az but that doesn't mean that it isn't also a Dob - witness equatorial mounts where you have German, horseshoe and fork (+wedge) mounts amongst others.  These are all equatorial mounts but they are also their distinct subcategories.  Same is true of a Dobsonian mount only it is an Alt-Az mount rather than equatorial. CrispMuncher (talk) 11:28, 14 July 2008 (UTC)
thread_title:  "Dobsonian Mount"? 

message: I cleaned up the edit up to 01:32, 27 September 2006. Sections of it seemed to just describe commercial types instead of Dobsonian evolutions and also read as a "how to" Buyers guide WP:NOT. "Truss Tube” was not "invented" in 1989 so need to more specificaly describe it as an evolution. Uncited claims such as "rigorous documentation to ensure their optical quality to the purchaser",  "better distribute the mirror box’s weight", and whole sections on current commercial models seem to be derived from ads and are therefor POV. RV'ed whole sections on "two generations" of Dobs since that doesn’t seem to be substantiated by sourced material. The rest of the changes are very good IMHO and I have simple re-arranged some of them to be more encyclopedic. (PS there are GFDL images of “Truss Tube” Dobsonians on Wikipedia Commons in case the immage supplied gets afD'ed. Will leave current image for now so its editor can supply a Copyright rational.) Halfblue 19:17, 27 September 2006 (UTC)
thread_title: Cleanup 

message: Dear Halfblue.  Thank you for comments – it’s great to see that there are others interested in this article.  I do disagree with you in many, many areas and I feel a few of your comments are quite subjective and POV (e.g. what constitutes “factual” and encyclopedic) but I’m hoping we can work together to refine this article.  The original article was a good start, but as an amateur with 30 years of experience, I feel that it had a very narrow breadth (focusing primarily on ATM’s) and does not encompass the full history or important aspects of this design.  Here are the major area’s I disagree with you on:
*First of all, I’m sensing a bias POV against “commercial” telescope manufacturers as engendered by your concern that the last edit “describes commercial adaptations instead of describing the designs in the amateur telescope making world where Dobsonians were really developed”.  Please bear in mind these designs were greatly improved on popularized by commercial makers (many of whom started as ATM’s). Most Dobs are bought, which make manufacturers highly relevant.  Some manufacturers, such as Coulter (e.g the “Volkswagon” of Dobs) and Obsession (which made the truss design popular) greatly changes the overall evolution of this design, and deserve mention.  
*Second, I complete disagree with your characterization that this is somehow a “How To” buyers guide.  Again, I’m sensing a bias against the discussion of anything commercial.  An authorative article on cars would likely mention the larger makers, and price ranges of typical model – it’s factually relevant to anyone trying to get an understanding of the subject.  The mere mention of a manufacturer does not mean its advertising.  The discussion of the differences of each type is no more of a buyer's guide than the pro's/con's section that existed earlier.  There’s nothing wrong with it or counter to Wikipedia’s policies.
*Truss Tubes are a very distinct and popular telescope, and deserve a separate category.  I earlier proposed “first” and “second” generation scopes, but perhaps the categories “classic” and “truss tube” may be better.  Commercial truss designs have been in their current form for 15+  years.  Having observed in California in the past 15 years I know that they’ve become the dominant scope by number at star parties, much in the same way C-8’s were 20 years ago.  I don’t feel that “Continued Evolution of the Design” is adequate – this a definite sub category recognized by most sources (e.g S&T, Astronomy, Etc.)
*I made no claim that the Truss Tube was invented in 1989, only that the first commercial models became available then, so I left this part in.  I’ve modified it though to pay homage to the ATM’s that likely developed this contribution.
*I’ve worked on some of the language your earlier took issue with (e.g “premium optics” and better weight distribution)
I’ve restored much of the content modified in respect to your earlier comments.  Please, let’s work together in developing sources and refinements.  Let’s not simply delete content wholesale because one of us happens to disagree with it.  Again, bear in mind that I’m writing this as a amateur astronomer with 30 years experience who has himself taught classes on the subject.  I have no vested commercial interested in any particular telescope or manufacturer.  Joeconsumer 09/27/06.
:Well... speaking as an amateur and professional telescope maker with a 35 year history I have to say... the article looks better, needs work, but looks better. When I talk about "encyclopedic" I mean that encyclopedic articles describe "things". The thing in question is a "design" so the article should describe the design, its origins, and its evolution, relevant additions ect. I have seen other articles where people want to describe a "design" via commercial models that are available. Commercial models may have their place but they are more a response to a market than a relevant landmark in a design. None of the innovations you attribute to commercial manufacturers are in fact "innovations". They all were in full swing well before some company picked them up. The Truss Tube existed way before the advent of the Dobsonian let alone its adaptation by manufacturers. And it was in full use practically in "first generation" dobsonians (have a look at my picture on the Amateur telescope making page and you will see Truss Tube Dobsonians lurking in the background in 1981). And when a manufacturer does pick up a design it lags the actual evolution... for example there is a greater than 20 year gap between the origin of the Dobsonian and the first Coulters. Commercial designs follow markets and tastes... so they are minimally relevant on a page about a design.
:Have a look at "cars". "An authorative article on cars" does not "mention the larger makers, and price ranges of typical model"... in so much as it lists landmarks in its evolution and commercial companies contribution to that evolution.   
:That's why I changed "Second Generation “Truss Tube” Dobsonians" to "Continued evolution of the design". There is no hard cutoff like you tried to characterize in your first edit. And the prevalence of commercial truss tube Dobs today are not a continuing evolution as much as a few commercial manufacturers' response to a market <--- and that gives you a sub-heading "Commercial applications".
:Working together on this is a good thing and Wikipedia recommends it for a good reason. Whacking the revert button may not be the best way to do that so I put forward my reasons and views...make what you will of them. Halfblue 04:46, 28 September 2006 (UTC)
thread_title: Re-Cleanup

message: All those mods you mention would be a good idea. I have made some more basic mods that may address some of what you mention. They will help categorize any additions to come. I find that you can always find help on Wikipedia its self. On of the first pieces of advice in article writing is What are you (we) trying to say? What we are trying to say is “There is a design, it has these applications, it has had these derivations”. In polishing up a quite a few articles on telescopes I have come across other peoples examples of organizing this type of information. The one I think will help here is Schmidt camera. I am making changes based on that. One line of thinking I am working along is that the "Dobsonian" is getting to be a historical artifact... the creation of one mind or group. So it should probably be discribed as a single or "classic" invention that then has derivations.
So:
*Introduction  (Wikipedia asks that this be short and sweet… hitting just the most relevant highlights) Some edits made there... mostly moves to more relevant sections.
*Invention and Design. (Covered pretty well)
*Applications ((Old article has that but this shows me that Advantages and Disadvantages needs to be moved up and needs to be made a sub heading)
*Derivative Designs (this is where information on amateur and commercial adaptations belongs. And those adaptations should be described in reference to the original design or concept.)
Material has been pretty muched re-arranged into their logical sections
These edits continue to follow this philosophy:
*Get it all in order. Avoid describing the design backwards. It needs to be A-B-C-D instead of trying to describe it from what we see today and working backwards. Get all information into their logical sub headings.
*Dig!!! Describe variations RE: where they came from (Wikipedia asks for citations when possible) errr… this may be hard since its seldom that one single person can or will step forward and say “I invented the rocker box mount”. But even superficial “digging” shows me that most design variations we are talking about here were not invented by commercial interests.
*Describe. Describe what the variations are, where they came from, and why an amateur or company used them.
Halfblue 16:51, 29 September 2006 (UTC)
thread_title: The Show So Far

message: I have rm'ed the following to talk since it is unreferenced and therefor WP:NPOV. Could be re-added if there is reference to someone actually saying this. Fountains of Bryn Mawr (talk) 23:09, 23 February 2009 (UTC)
replies: text: The term "Dobsonian" is considered objectionable by some purists since the Dobsonian telescopes are just Newtonian reflectors with a simplified mechanical design. Normally, proper names for telescope designs are associated with the optics (Cassegrain, Maksutov, Ritchey-Chretien etc.) and not with with the way in which the optics are mounted.
I put it back. The second sentence is quite correct; do you know of any exceptions? And as a long-term amateur astronomer, I can attest to the accuracy of the first sentence.IrishFilmBuff (talk) 09:54, 24 February 2009 (UTC)

text: We usually don't add more unreferenced opinion to an article just because other stuff exists. The description part of the first sentence is redundant to the intro and .... "considered objectionable by some purists"? --- who?WP:V. You may be able to "attest" but we can't go by that WP:OR. And there are exceptions of telescopes named after the way they function such as Solar telescope, Turret Telescope, springfield telescope. The best we can say is that "Dobsonian" describes a newtonian of a specific mechanical design, and i think that is stated in the intro already, although we could say "The term "Dobsonian" or "Dob" refers to a specific mechanical design for a telescope with an alt-azimuth mount and a Newtonian telescope tube assembly that feature several innovations made popular by John Dobson." Fountains of Bryn Mawr (talk) 13:48, 24 February 2009 (UTC)
thread_title: objectionable?

message: I certainly agree with whomever added the "peacock" label. This article is terribly biased. Dobsonian telescopes sacrifice everything for the sake of large aperture. They are a huge step backwards in almost every respect but size. A person who learns about Dobsonians from this article would get a totally wrong impression.JBHarshaw (talk) 11:55, 25 February 2009 (UTC)
thread_title: Biased!

message: Concerning the edit summary comment: "BY DEFINITION, Dobsonians have lower-quality mirrors than ordinary reflectors:  I have an 8" pyrex blank sitting under the piano that I hope to start grinding before too long.  By your definition I am prohibited from placing it in a dobsonian structure if I manage to polish too fine a figure???  That is preposterous on its face.  --Kbh3rdtalk 23:50, 25 February 2009 (UTC)
thread_title:  "By definition..." 

message: I have re-edited the page based on the only objectified description of a Dobsonian telescope's optical performance characteristics---> they are newtonian telescopes. Since the optics in a dobsonian run the same gamit from good to bad as found in any other amateur or commercial telescope they really have no other definition optically. Their mounts have a similar definition---> they are Altazimuth mounts. rm'ed some redundancy as well as text that does not fit the definitions above. Fountains of Bryn Mawr (talk) 00:47, 11 March 2009 (UTC)
thread_title: By definition redux

message: User 74.42.36.182 raises a very interesting issue that we have often discussed at the Vancouver Sidewalk Astronomers (VSAs):  What is a Dobsonian?  Our group has several Dobs.  We also have one vintage (ca. 1940) 16 inch Newtonian reflector on an alt-azimuth mount. The younger VSA members insist on calling that telescope a "Dobsonian", but I never tire of explaining to the young-uns that it was built decades before John Dobson arrived on the amateur astronomy scene.  When I read old astronomy books and magazines, I see pictures of telescopes that would nowadays be called "Dobsonians" -- but they all pre-date John Dobson. So what, exactly, makes a telescope a "Dobsonian"?
Here are some things that are NOT specific to Dobsonians:
* Optical design. Dobson used a standard Newtonian optical train.
* Mounting.  Fork-mounted alt-azimuths have been around, like, forever. (Russell Porter? How about Lord Rosse? William Herschel? etc.)
* Large aperture. At my very first star party (1962) I distinctly recall a 20" truck-mounted reflector.
* Innovative materials -- cardboard tubes, wooden bases, makeshift bearings -- all were in use around the time that I got started in the early 1960's.  Cash-strapped amateurs have been finding innovative ways to use common materials since the earliest days.  My first reflector made liberal use of parts from an auto junk yard.
Even the specific combination of elements is not unique to John Dobson.  If you don't believe me, take a look at Sam Brown's pamphlets on telescope making from the 1950's (published by Edmund Scientific) -- you will find designs for telescopes that contain all of John Dobson's supposed innovations. But, they are not called "Dobsonians", because Dobsonians had not been invented yet.
Still, most amateur astronomers seem to have something definite in mind when they talk about "Dobsonians". What, exactly, is that, and how does it differ from what came before? That is a key question which this article needs to address, and this is why I undid Fountains_of_Bryn_Mawr's deletions. I have also added a link to an article that cites Dobson's own definition of a "Dobsonian".67.208.5.162 (talk) 16:35, 2 August 2010 (UTC)
replies: text: You expanded on a series of unverified and probably untrue statements, I have rm'ed those first two sentences (see "objectionable?" talk above). Also lead sections are for summarizing articles (WP:LEAD) so I have reworded the rest to fit that guideline. Fountains of Bryn Mawr (talk) 20:46, 2 August 2010 (UTC)

text: The issue here is what distinguishes Dobsonians from other things -- i.e., why is there a separate class, and name, for these telescopes.  This deserves discussion right at the start of the article. I've also removed the fatuous sentence about the "design continuing to evolve". The more the design evolves, the more it looks just like pre-Dobsonian telescopes, since commercial dealers and serious amateurs are doing away with the crude construction techniques that are the sole defining element of Dobsonians.67.208.5.162 (talk) 13:29, 6 August 2010 (UTC)
replies: text: Thank you for your edit, it has been reverted. The opinion that "crude construction techniques" is the "defining element of Dobsonian" can not be the basis for additions to an article per WP:NPOV. Other additions must pass WP:PROVEIT and again not be opinion. Fountains of Bryn Mawr (talk) 17:09, 9 August 2010 (UTC)

text: Hmmm...Fountains, I've spent some time going over your edit history. You seem to have a penchant for imposing your personal point of view on otherwise balanced articles, and invoking one or another of WP's many policies to justify your biased point of view. I'm on to you! 67.208.5.162 (talk) 22:44, 25 September 2010 (UTC)
replies: text: Sorry you have that opinion and feel the need to ignore Wikipedia policies and guidelines, such as not making personal comments on talk pages. You may be more happy in another project where you can actually express (impose?) your own opinions. Fountains of Bryn Mawr (talk) 03:04, 26 September 2010 (UTC)
thread_title:  Reversion of edits by Fountains of Bryn Marr 

message: This talk page (and these SPI and ANI reports) show a high number of edits from differing anonymous IP addresses and identified sock-puppet accounts that all probably belong to one user. If you have been referred to this talk after restoring one of these edits you should provide reliable sources before restoring and maybe consider creating an account. Fountains of Bryn Mawr (talk) 17:09, 28 September 2010 (UTC)
replies: text: The reason is WP:PROVIT, as bona-fide as it gets. The first two statements are unreferenced (WP:V). The rest is redundant refactoring of material already in the article. Fountains of Bryn Mawr (talk) 04:03, 2 October 2010 (UTC)
replies: text: The sentences are now referenced. Please don't delete this paragraph yet again; doing so violates WP:NPOV. 67.208.5.162 (talk) 19:42, 3 October 2010 (UTC)

text: I have added yet another reference. I hope that this one meets your exacting standards. 67.208.5.162 (talk) 12:21, 4 October 2010 (UTC)
replies: text: The standard you should be adhering to in not mine, its Wikipedia's, namely Wikipedia is not a publisher of original thought. The claim that "Dobsonians" exceed a "rule"  is not supported (that has to be someone else's thought, not yours). New ref only cites that there are optical types with specific names, not that there is a "rule" or that there can't be other types (which there are). Rest is still redundant (not addressed at all). reverted. Fountains of Bryn Mawr (talk) 20:26, 4 October 2010 (UTC)

text: There you go again: Invoking a new reason each time for reverting my edit. What remains constant is your determination to keep this article from being improved. I think it is time to take this to a higher authority. 67.208.5.162 (talk) 00:40, 7 October 2010 (UTC)
thread_title: POV "Dobsonian definition"

message: Among the advantages outlined for the Dobsonian, the article says:
Since the telescope design has an alt-azimuth mount the mirror only has to be supported in a simple cell with a backing of indoor/outdoor carpet to evenly support the weight of the much thinner mirror.
I'm afraid I don't follow that.  Might one not be just as apt to point a Dobsonian in any direction that you might point a typical Newtonian scope with equatorial mount?  So the mirror would have the same strains.  If it has to do with the box that holds the mirror, is there any reason not to put that box in a typical Newtonian scope with equatorial mount? Uporządnicki (talk) 18:10, 20 August 2015 (UTC)
replies: text: Its not where you point it, its the orientation the tube ends up in. People who use EQ mounted newtonians almost immediately hit the situation where "damn, the eyepiece mount is upside down!!!". An EQ mount can orientate the optical tube (and the mirror) at an infinite number of angles and even upside down, meaning you need a complicated cell that can support the mirror at all orientations. The basic dobsonian design only tilts in one plain, 90% to 0%, so you only need to support the mirror back and one side, usually with some form of cradle or strap along that edge. Fountains of Bryn Mawr (talk) 19:32, 20 August 2015 (UTC)
thread_title:  Possibility of thinner mirrors needs clarification 

message: I cant figure out how to use wikipedia to properly edit the article.  The Orion 50 inch dobsonian was never produced, it was a market test.  http://www.cloudynights.com/topic/323598-orion-monster-dobs-not-happening/  They made a 36 inch which had some apparent problems, the offered 42 and 50 inchers were never even made as a test.  
The largest Dobsonian actually produced and sold commercially to my knowledge is a 36 inch by Obsession which is no longer available either, although other makers have said they would consider making 36 and 40 inch scopes.
Also the largest homebuilt dobsonian scope is currently a http://www.davidreneke.com/the-worlds-largest-amateur-telescope/ 70 inch still being completed.  It is not in this list of other largest scopes which are probably all dobsonians.  http://www.bbastrodesigns.com/Largest%20Amateur%20Telescopes.html
— Preceding unsigned comment added by 75.168.128.95 (talk) 20:04, 8 July 2016 (UTC)
replies: text: The sources are kind of thin as far as Wikipedia goes, blogs/personal websites/message boards are not considered very usable. The article itself is not much better so this could be added in some way. Fountains of Bryn Mawr (talk) 21:22, 8 July 2016 (UTC)
thread_title: NEW CORRECTION BY A TOTALLY DIFFERENT USER

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thread_title:  External links modified 

message: If no objection, I propose to remove the "largest commercially available... 50-inch aperture", since Orion never did produce that years ago. Also plan to update that section with some newer information.  (No, I am not a Dob seller :-) Assambrew (talk) 22:32, 18 June 2020 (UTC)
replies: text: Sounds good to me. Fountains of Bryn Mawr (talk) 22:41, 18 June 2020 (UTC)
replies: text:  Thanks, that was quick. I'll get to it soon. Assambrew (talk) 03:49, 19 June 2020 (UTC)
replies: text: Last time I really looked at commercial dobs they were Coulters ;) Now days when I do astronomy events I am surrounded by 21-24 inch goto monsters. Good for someone to update the commercial end. Fountains of Bryn Mawr (talk) 15:38, 19 June 2020 (UTC)
replies: text:  I had a Coulter Odyssey 8 myself back in the day. Okay, first change I made was to replace the mini-Dob photo with an example of a truss Dobsonian. Hope I did the fair use image stuff right, rather new to that stuff. Still working on the text, I will summarize changes here. Assambrew (talk) 23:59, 21 June 2020 (UTC)
thread_title:  Commercial adaptations