Talk:Telescope

Old comments

Problem: a statement under "X ray and gamma ray telescopes" says that the Earth's atmosphere is opaque to these parts of the electromagnetic spectrum. However, cosmic gamma rays are very high energy and routinely pass through the atmosphere. They can be detected at the Earth's surface. Can you explain your "opaque atmosphere" statement, clarify it, or correct it? 24.8.181.28 01:53, 18 April 2007 (UTC)KPN

I have remove the following statement, which I think correspond not to spherical aberration but field curvature. -- looxix 19:33 Apr 21, 2003 (UTC)

Some schmidt cassegrains have intentional spherical aberration, and compensate with a film-holder that stretches the film into a mild spherical shape.

The Telescope mountings para is largely incomplete lacks equatorial and meridian mount. Ericd 01:47 Apr 22, 2003 (UTC)

I am not conviced by :

"The phenomenon of optical diffraction sets a limit to the resolution and image quality that any telescope can achieve. We still do not know when this limit will be reached, but most astronomers believe we will reach it sooner or later."

IMO diffraction occurs with a small apertures and research telescope have large apertures.

But, I'm not a specialist. Ericd 17:56, 2 Oct 2003 (UTC)

You can read about the influence of diffraction on resolution limits at the [link provided at the bottom of the page, but I'll clarify in the article. Nixdorf 23:08, 3 Oct 2003 (UTC)

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Would anyone be interested helping with a Wikipedia:WikiProject Telescopes and/or Wikipedia:WikiProject Space Telescopes? Should a telescopes template include space telescopes? It/they could be modeled after the following articles:

• Wikipedia:WikiProject Astronomical Objects
• Hubble Space Telescope
• Spitzer Space Telescope
• Arecibo Radio Telescope

--zandperl 15:23, 16 Feb 2004 (UTC)

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The article doesn't seem to mention photography through telescopes. I'm not sure if it should, but I was looking for that. --blades 10:05, 30 May 2004 (UTC)

Synthetic aperture vs adaptive optics

It is my understanding that synthetic aperture refers to a technology for radio telescopes, while adaptive optics is an entirely different technology used for optical telescopes. But this article seems to use synthetic aperture for both. (It might even be using the term to cover interferometry, in one instance). Am I mistaken - does synthetic aperture apply to optical telescopes ? -Willmcw 06:47, 11 Dec 2004 (UTC)

Umm, I am not an expert, but yes, both techniques are applicable to optical telescopes. Both are important and should be described. Briefly:

Adaptive optics refers to a set of techniques for distoring the received wavefront to correct for measured distortions along the optical path (e.g. effects of the atmosphere). They are being used with great success in many new telescopes.

Synthetic aperture refers to a set of techniques for combining information from several telescopes at one time or the same telescope at different places, for instance, to approach the resolution of a much larger physical telescope (one with a larger aperture). Synthetic aperture techniques have been employed for many years, with great success, in so called "sideways looking" radar and sonar systems, for instance. Optical and radio telescope arrays are synthetic aperture techniques. --AJim 04:58, 20 Dec 2004 (UTC)

Just linking the existing entry on Aperture Synthesis (AS) to the this discussion. AS as used in the Very Large Array allows the VLA to operate in at least 4 different modes (1) giving astromers varying magnification capabilities. A similar optical configuration is demonstrated in the Very Large Telescope. This last case also uses Adaptive optics to cancel out atmospheric distortion to near exoatmospheric levels and aperture synthesis of up to four stand-alone telescopes.

A "third" technology being implemented in the James Webb Space Telescope boasts some interesting benefits. Active Optics allows the development of super-lightweight mirrors which can be collected together to perform as one larger unit. The JWST primary mirror is a system of eighteeen smaller mirrors (1.3m) which are phase-synchronized to produce the capabilty of a single larger unit. Just to quantify the gain, the JWST as reported by NASA, will be equipped with a primary mirror that has a diameter of 6.5m versus Hubble's Primary Mirror (2.5m)(2), yet 1/10th the weight. In fact, "if Hubble's [primary] mirror were scaled to match [that of the JWST] it would be unlaunchable. There isn't a launch system capable of supporting a [payload of the required size and in weight]"(2).

COMPARING THE THREE

Active Optics systems differ from both synthetic apperature and adaptive optics. As noted above, "adaptive optics" are used to correct some depreciation of information collected by the mirror. "Synthetic Aperature" systems rely on comparing the collected information derived from two (or more) spatialy distant observation points (OP); these calculations are greatly affected by the know position and inter-relationships of the OPs. SAs also allow obersavation systems to retrieve information from obscured points of interest (e.g., clouds covering the Martian surface) by way of differential measurement. "Active" optics allow a system of mirrors to integrate into one larger unit and provide faster correction capabilities.

(1) - 'NRAO Very Large Array: Configurations'

(2) - 'NASA's James Webb Space Telescope Information Website'.

--'User:CSR' 15:12 UTC, 051202

Largest Telescope in 19th Century

I'm not sure if it's true, but I've often heard that the Ross Castle Telescope in Birr, Ireland was the largest telescope for over 50 years (which 50 years is disputed :)). This information is on the Birr page in Wikipedia (http://en.wikipedia.org/wiki/Birr). Perhaps it would be good to explain how the 91-cm refracting telescope at Lick Observatory be bigger than the 72-inch reflector at Birr?

Good catch. It may take some careful research and writing, but the difference may be between whether the telescopes are usable for science. There have been several large telescopes that were not usable. I understand that the Birr telescope was marginally useful, but someone else may have better information.-Willmcw 19:41, 3 Jan 2005 (UTC)

Suggested changes

If no-one has any objections, I will copy the section "Famous optical telescopes" to the optical telescopes page, and alter the section on this one so it lists "Famous telescopes" (including non-optical telescopes e.g. Chandra, the VLA and ALMA). This would make the section better matched to the article. Rnt20 11:52, 4 Jun 2005 (UTC)

Only astronomical?

The opening sentence -- 'A telescope is an astronomical tool' -- is incorrect. Astronomical telescopes are, it seems, the most interesting in terms of large-scale progress, but historically, telescope uses features more strongly in military and navigational contexts (then, as now, that's where the best funding tended to come from). The opening paragraph should therefore not define telescopes as purely for astronomy, but instead indicate that this article is primarily about astronomical telescopes - and perhaps it would be worth indicating where to find articles about other kinds of telescopes (such as hunters' binoculars, photographers' telephoto lenses, opera glasses).

--69.177.103.38 22:51, 26 December 2005 (UTC)

This can be done. --Excaliburo 15:19, 27 December 2005 (UTC)

Euro50

I just read a Swedish newspaper article on the Euro50 telescope project, planned by a multinational consortium (Finland, Ireland, Spain, Sweden and the UK). It has no WP article yet as far as I can see, but there is a website devoted to it here, in case anyone is interested in writing something about it. up◦land 10:55, 12 March 2006 (UTC)

Largest Optical Telescope

Aloha,

I would note that SALT (South African Large Telescope) is, I believe, a fixed-altitude design like the Hobby-Eberly telescope in west Texas. They're based on the Keck design, but with no up-down tilt, using a movable secondary mirror or prime focus instead, and I have heard that this limits their use to spectroscopy, as opposed to actual photometric imaging. Also, if SALT is identical the HET design, it may use an "oval" mirror, 11m by 9m, as opposed to Keck's "round" 10m diameter one. (I put the words in quotes because all are made of hexagonal segments.) Since HET is only 9m across in one direction, it has been considered "smaller" than Keck.

GTC in the Canaries is has a full altazimuth mount, I think, and at 10.4m would definitely surpass the Kecks size-wise. Bold text

Leonard Digges

His invention of his telescope (1570s according to article) doesn't match his age, he died more than 10 years before in 1559

Copyright Violation in Types

Last night I tagged the entire types section as a copyright violation. There were two brackets on the end, and when I Googled the text, it came back (word for word) to a Galileo website. Nwwaew 11:22, 19 September 2006 (UTC)

"Telescope" and "Optical telescope"

These two articles seem to overlap and contain redundant sections in respect to each other. It looks to me like large sections of Telescope should be moved off to Optical telescope for the following reasons:

History - this section is about the history of optical telescopes only-- it should be moved off to Optical telescope.

Types of telescope - this section is about types of optical telescopes only-- it should be moved off to Optical telescope.

Imperfect images - this section is about the image properties of optical telescopes only-- it should be moved off to Optical telescope.

Famous optical telescopes - By definition this should be moved off to Optical telescope.

I will take a whack at this soon unless there is outcry to the contrary Halfblue 05:45, 7 January 2007 (UTC)

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I did a cleanup of the page.

• Focused article towards "telescopes" in general.
• Moved stuff related to Optical telescopes off to Optical telescopes
• Cleaned up redundent "See also" links and expanded "Famous telescopes" list and alphabatized.

Halfblue 00:46, 10 January 2007 (UTC)

Seems a bit confusing at first

Regarding the suggestion of this article having a history section, I was just thinking the same thing and decided to look into it. It seemed to odd that such an article could have had something like the history overlooked. It used to have such a section like this, but the article was over-lapping with Optical telescope, and most of the content went there. While I guess that is a good move, it makes me wonder if Optical telescope should occupy the article title of Telescope, due to the general reader likely assuming that is what the article is about. Thoughts? -- Ned Scott 01:28, 17 May 2007 (UTC)

Great minds think alike, I guess. I'll leave this up to others to decide, as I don't know a whole heck of a lot about the subject, but it seems like some form of history section, maybe even just a brief one with a link to History of telescopes, would be appropriate. I do agree that the word "telescope" is probably more strongly associated with the optical variety. Thanks for looking into the matter. --Bongwarrior 01:56, 17 May 2007 (UTC)

I did that original move of all content over to Optical telescope since it was a logical move given that we had two articles- Telescope and Optical telescope and we had whole sections in Telescope like Famous optical telescopes. I did not question why there are two articles. It's a good question. At this point this article is like a massive disambiguation page linking out to all the sub topics, Optical telescope being one of them. And maybe that is the way it should be, there are alot of "telescopes" out there. Adding even just a history to this page may get cumbersome since the question would be "whose history do we add?" - Just Optical?, Radio?, Gamma Ray?. I would suggest that an explanation could be added to the intro as to how these things got named "Telescopes" with maybe a link such as (see also:History of telescopes). Good information on where the word came from at [1] and [2]. Halfblue 04:33, 17 May 2007 (UTC)

Articles for creation needs your input!

Hi there! An anonymous contributor has made a proposal in today's (27 May) entries that I believe requires an expert's opinion. If this is no longer today, you can find it at Wikipedia:Articles for creation/2007-05-27. I'd appreciate it if you could review the request, and either accept or decline. Alternately, if you are uncomfortable with the process at WP:AFC, please let me know here or on my talk what you recommend and I will do the grunt work! Thanks again for your help.--Xnuala (talk)(Review) 21:13, 27 May 2007 (UTC)

This issue has now been resolved.--Xnuala (talk)(Review) 01:11, 31 May 2007 (UTC)

Eye damage

If someone were to look through the eyepiece of a telescope aimed at the sun on an overcast day (during the day) with a UV index of 1, but the person had his/her eyes shut while doing it (and did it for a few seconds), would the person's eye(s) be damaged by the sunlight or UV rays? Latitude0116 (talk) 19:34, 17 January 2008 (UTC)

Was the telescope really "Galileo Galilei's instrument"?

The telescope article implies that Galileo Galilei invented the telescope. According to the Hans Lippershey article and the Galileo Galilei article, among others, Galileo was the first to use the telescope to look into space, but he modeled his telescope after a telescope already in use by the Dutch government. KayaKai (talk) 16:22, 30 March 2008 (UTC)

I think there needs to be a history section, summarizing History of telescopes. Crum375 (talk) 16:32, 30 March 2008 (UTC)

The history section had problems. It did not fit the article because the article is an overview all types of telescopes. "History" only covered Optical types and is a redundant version of what already appears at Optical telescopes. I have removed the section and intergrated some content into intro to fix problem noted by KayaKai. Fountains of Bryn Mawr (talk) 03:29, 7 April 2008 (UTC)

I understand, but a brief overview of the foundations for this invention — and it's future-classes, should be noted.[3] Does that seem reasonable to you guys? Well, let's stop beating around the bush and just merge the two articles. Almost every main article of common interests has a history section. Is not the telescope as fundamental as any other invention? InternetHero (talk) 21:18, 28 June 2008 (UTC)

The concept of an overview article is that it sends you to a specific article for what you are looking for. So no, the main article would not have a history section; it would be contained in the relevant article such as History of telescopes. Please also see your talk for other reasons why this material is not suitable for inclusion here. Fountains of Bryn Mawr (talk) 19:46, 29 June 2008 (UTC)

You're, right. I do think that "an instrument" in the form of a magnifying device is what a telescope ecompasses. To be fair, my edits conform to that idea, so just added it to the summary instead. The sources are well established already and it looks like you're new to Wikipedia so I will try to help you out with the rules. Try this website: [4]. InternetHero (talk) 22:32, 29 June 2008 (UTC)

hmmm... don't see how my edit record could be called "new". The article is Telescope. The contributions of Ibn Sahl and Ibn Al-Haytham belongs at History of optics, and History of telescopes (in a balanced fashion). Adding two paragraphs in a three paragraph intro at Telescope brings up WP:UNDUE problems. We are talking about the telescopes here, optical, radio, UV, etc. An intro should summerize the article, not make unsubstantiated blanket statements on topics the article is not about (WP:INTRO). http://online.physics.uiuc.edu/courses/phys199epp/fall06/Powers-NYTimes.pdf is a single newspaper article that gives opinion but that is not the same as a reliable source. As far as rules.. please keep in mind WP:3RR. Fountains of Bryn Mawr (talk) 00:14, 30 June 2008 (UTC)

No problemo. I will just add the information about the telescope in regard to Al-Haytham. The telescope is a device to magnify distant objects, but simply stating that a radio, or electromagnetic telescope contradicts the foundation of the latter is highly dubius. I see no argument here, but rather 'an agreement to disagree'. InternetHero (talk) 13:10, 30 June 2008 (UTC)

I have re-edited the intro and added a history section. Intro now summarizes article (WP:INTRO). Ibn al-Haytham is pre-telescopes and more related to history of optics so did not cover him. Leonard Digges, and Taqi al-Din mentions have thin references and are WP:UNDUE. They are covered in a more detailed balanced fashion in History of telescopes which is now linked. Fountains of Bryn Mawr (talk) 04:39, 9 July 2008 (UTC)

WP:INTRO: "It should establish context, summarize the most important points, explain why the subject is interesting or notable, and briefly describe its notable controversies, if there are any."

I don't see why your opinion contradicts someone like Richard Powers... I am going to revert back to my edit now. I hope we don't need an admin. InternetHero (talk) 20:52, 17 July 2008 (UTC)

Please do not make POV edits. Absolutely no reliable sources state that Ibn Al-Haytham invented the telescope in "the beginning of the 13th century century" Not even the Richard Power ref. And one Richard Powers ref does not "fairly representing all majority and significant-minority viewpoints that have been published by reliable sources". Controversy is handled in History of telescopes... within reason and reliable sources. Fountains of Bryn Mawr (talk) 16:34, 19 July 2008 (UTC)

You're right. I changed it a little to fix it. Actually, I have about 3 secondary sources and one tertiary source I just found. Al-Haytham was very instrumental to the telescope and its history/summary. I'm sorry, but "Fountains of Bryn Mawr hasn't wrote any books nor is he respected to the likes of Richard Powers. Until F of BM actually becomes her/his own source to directly refute my arguement, I have absolutly no intention of leaving such innaccuracies to this article. InternetHero (talk) 21:47, 19 July 2008 (UTC)

"Being your own source" is directly contrary to the official English Wikipedia policy of WP:NOR. The source is not in question. It's use is. The addition of Al-Haytham is not a summery of History of telescopes. Singling out Al-Haytham in the total history of people who contributed to the history of optics is WP:UNDUE. Sources cited don't support this POV (see: Talk:History of telescopes#Ibn Al-Haytham). And previous editor should see WP:CIVIL. Fountains of Bryn Mawr (talk) 22:58, 22 July 2008 (UTC)

LOL. The summary defines he telescope as an insturment that magnifyies istant objects. The first man to do this was Al-Haytham. I think you are a racist person. If someone like Richard Powers writes that Al-haytham has a history with the telescope, then nothing YOU can say will refute that unless you become more respected than him. This is laughable... InternetHero (talk) 02:12, 23 July 2008 (UTC)

Richard Powers

Does "Fountains of Byn Mir" override the opinion of the great novelist, Richard Powers??? I'm just wondering since I just thought that if you provided a reference, you are able to post on Wikipedia as long as it is verifiable and according to the other three pillars. Why does "Fountains of Byn Mir" think his opinion overrides a person like Richard Powers??? Richard stated that Ibn Al-Haytham was fundamental to the telescope and his research laid the foundatinos for telescopic technology. Read CAREFULLY:

So did Ibn al-Haytham's optics. His work on refraction and lenses led to the development of the telescope and microscope. Once these devices threw open their portals onto the invisible, there was no looking back. Van Leeuwenhoek's (1632-1723) "tiny animalcules" revealed the living world to be stranger than any natural philosopher could have guessed.

The reference. InternetHero (talk) 02:23, 23 July 2008 (UTC)

Addition to the Summary or Chapters

I can add it to the summary, but it looks nicer in the chapter since the microscope article has the same editor-style. There are radio telescopes and electro-magnetic telescopes, but they're all instruments used to magnify objects. Simply stated, Al-Haytham made an instument to magnify objects.

Anyway: WP:NOT#Wikipedia_is_not_a_dictionary:

Although articles should begin with a definition and description of a subject, they should provide other types of information about that subject as well.

[5]:

Definitions are too narrow if they exclude some things that they should apply to; they fail to describe some members of the word's extension. Here is an example of a narrow definition: 'piece of furniture' means 'object used to sit on'. Of course, some pieces of furniture are not used to sit on; for example, we put objects on them (like tables) or in them (like a chest of drawers) or we put our feet on them (like footstools), and so forth. So even though some pieces of furniture are objects that are used to sit on, not all furniture is. We need a broader definition: we might add other qualifying characteristics, like 'used to put feet up on' or 'used to put household objects on', for example. That would make the extension of the definition bigger — that is, the definition would apply to more things, and more of the things that we use the word 'furniture' to describe. We might also choose to entirely rewrite the definition, since "laundry lists" of seemingly disparate characteristics strung together by 'or' are probably not truly describing a single concept.

Thanks for your time. InternetHero (talk) 09:30, 23 July 2008 (UTC)

You keep missing the point of WP:UNDUE, WP:NPOV, WP:INTRO, and WP:SOURCES. Quoting one novelist (Richard Powers) as a reliable source to back a claim the an single individual (Al-Haytham) made a more significant contribution than all the other people listed in History of optics violates all those guidelines. You have now been reverted by three different editors on this. You should start listening to them. Fountains of Bryn Mawr (talk) 17:15, 23 July 2008 (UTC)

That's the POINT. Al-haytham WAS that important. I think I'm going to get an administrator now. You're not a reliable source nor do you have any respect to the likes of Richard Powers. Your opinion on this matter is conflicting with a credible and reliable source who has written novels extensively. What, may I ask, have you done? Why do you think your opinion overrides a respected author??? This boggles my mind. InternetHero (talk) 20:43, 23 July 2008 (UTC)

Discuss the content, not the contributors. Editors don't matter, edits do. Please stay away from anything resembling personal attacks. --lifebaka (talk - contribs) 20:59, 23 July 2008 (UTC)

If this guy is that important, there should be a mention of him in the article, however, his coverage needs to be relative to his importance in the subject matter. Useight (talk) 21:54, 23 July 2008 (UTC)

I need to ask a question of you, InternetHero: Does Richard Powers have any published non-fiction works on astronomy, telescopes, or anything closely related to those? About sourcing, it'll take more than just Powers to verify this lofty claim. This is of interest, but it merely says that he laid the foundations of modern optics, not the development of the telescope. If anyone could locate the book Ibn Al-Haytham: First Scientist by Bradley Steffens (Morgan Reynolds, 2006) that may also be helpful. A Google Books search yields little to nothing relating Al-Haytham to the telescope - only to optics in general. InternetHero, you'll need to provide a source other than Powers (even if he does satisfy the criterion I asked a question of above) in order to refute the fact the well-known books on the history of the telescope (example) mention nothing about him. Nousernamesleft (talk) 22:27, 23 July 2008 (UTC)

That's not to say that Al-Haytham doesn't deserve a passing mention in relation to optics - he does regardless of whether another source can be found. However, to warrant the lofty description he holds in the text right now, more is needed. Nousernamesleft (talk) 22:28, 23 July 2008 (UTC)

Edit war

Going back only the last 24 hours, I found these: InternetHero added the content here, here, and here. Fountains of Bryn Mawr removed the content here and here. I also note a conversation happening in the edit summaries including an uncivil comment. There was plenty more edit warring if I go back more than one day. This needs to be sorted out on the talk page rather than on the article. Useight (talk) 21:45, 23 July 2008 (UTC)

I was contacted by InternetHero - I have no idea why; possibly because of my involvement in the Islamic astronomy article(?) Anyways, to tell the truth, I have little expertise in this area, to tell the truth, though I'm sure that InternetHero's replacement of a paragraph with different one with no overlap was inappropriate - if it turns out that the events that you mention warrant inclusion in the article, please add them on instead of replacing existing content, InternetHero. Anyways, is it possible for you (InternetHero) to please present the sources that you say back up your claims? (By the way, Useight, would a full protection of the article be warranted in the meantime? I don't often work with page protection, so I'm not sure...) Nousernamesleft (talk) 22:16, 23 July 2008 (UTC)

Ah, sorry, missed the section with the argument above. I'll take a look. Nousernamesleft (talk) 22:17, 23 July 2008 (UTC)

I've just gone ahead and let both sit in the History section now. Should make everyone happy. Some sources besides Richard Powers would be nice, though, since only using him does seem kinda' odd. Anyways, I hope this is a workable compromise. Cheers. --lifebaka (talk - contribs) 22:25, 23 July 2008 (UTC)

I'm sorry, but I really don't think it is - inclusion of the other paragraph isn't the main issue. Nousernamesleft (talk) 22:29, 23 July 2008 (UTC)

Hmm, point, but it at least gives us something people won't hate for a while. So we can calmly discuss things here. I'd personally not mind a mention of Al-Haytham here, but mostly it should probably be at history of optics instead. Can we deal with my version temporarily? --lifebaka (talk - contribs) 22:35, 23 July 2008 (UTC)

I too was solicited by InternetHero to intervene on his behalf. After reviewing the History entry, I find it lacking unity of voice and self awareness; furthermore, the flavor of the Ibn al-Haytham references does not merely inform but provides an assessment -not in keeping with WP:NPOV, and, with such, weighs the section WP:UNDUE.Mavigogun (talk) 23:14, 23 July 2008 (UTC)

The Telescope#History section should be a summary for History of telescopes. There are 3 sentences at HOT on al-Haytham. There have now been 2 sentences added to the main article, yet the lead of HOT doesn't even mention al-Haytham. I believe it may be undue weight to be putting such an emphasis on al-Haytham in the main article. DigitalC (talk) 00:12, 24 July 2008 (UTC)

So did Ibn al-Haytham's optics. His work on refraction and lenses led to the development of the telescope and microscope. Once these devices threw open their portals onto the invisible, there was no looking back. Van Leeuwenhoek's (1632-1723) "tiny animalcules" revealed the living world to be stranger than any natural philosopher could have guessed.

The reference.

I agree that the rather strong conviction were unjustified and unwarranted. I diagree to "a passing mention" as that would qualify as being an overly narrow definition since most people recognize a telescope as the one found in schools—not high-tech laboratories. To be absolutely fair and justified, both the 11th and 17th centuries were instumental to the history of the telescope: without the the European lensmakers and craftsman, the telescope might not have been invented: without the Arab glassmakers and researchers (especially Al-Haytham), the telescope might not have been invented. I think—and hope—everyone can agree on this. InternetHero (talk) 02:23, 23 July 2008 (UTC)