Talk:Celestial spheres

Spheres and orbs

I was recently reading Pierre Duhem's Le Système du Monde, vol. 2, p. 123, where he presents the following text from Alhazen (in French translation of a Latin translation of the original Arabic): "Les sphères des trois planètes supérieures... sont absolument semblables entre elles, et par le nombre des orbes que les composent...."

Perhaps Duhem's use of these two different synonyms suggests a way out of our problem of counting spheres. Why not consider the planets' spheres as made up of numerous consitutuent orbs. Such a terminological distinction would limit the number of spheres to the seven planetary spheres, the stellar sphere, and the other spheres mentioned in the introductory section, in more "popular" discussions and illustrations, and elsewhere. Each planet would then have its constituent orbs resulting in the different totals found for Eudoxus, Callipus, Aristotle, Ptolemy, etc. Alternatively, we could consider the planets' orbs to be made up of constituent spheres; the main point is to establish consistent use of these two synonyms within the article.

I'm considering running through the article to work for consistency on this terminology, which would make a complicated system clearer to a reader. I'd like comments before I take the effort involved. --SteveMcCluskey (talk) 19:49, 29 December 2009 (UTC)

We would need a reliable secondary source to support an interpretation, or re-interpretation, of this sort. I also doubt that orb and sphere have different meanings in the context of pre-modern astronomy. The two words exist because orb derives from French via Latin, while sphere derives from Greek. Dictionaries have a definition for both words as meaning what the article calls the celestial spheres. In the title of Copernicus's main work, orbium is usually translated as "spheres", but sometime as "orbs".—Finell 04:26, 30 December 2009 (UTC)

Of course, you're right. I was just hoping for a consistent way to use these synonyms to achieve simple rhetorical clarity in the article. If it won't work, we'll just have to struggle with something like "total orbs" or "concentric spheres" (the latter used by Grant) and "component spheres", "constituent spheres", or even "eccentric spheres" for the parts that make up the whole. Perhaps your copy-editors eye could see a way through this.--SteveMcCluskey (talk) 13:48, 30 December 2009 (UTC)

The terms' meanings and the concepts that they represent were not used consistently by each author or in each period. It became a patchwork of "fixes" to "save the appearances" (i.e., to explain the planets' observed positions while clinging desperately to the ancient ideal that celestial motions must be perfect circles). Statements about the physical makeup or properties of the spheres themselves (that is, other than the orbits, which had to conform to observations) were entirely products of philosopher-astrologer-astronomers' imaginations. Subsequent scholars (our secondary sources) have tried to make out a neat, consistent system from the mess, and they (unsurprisingly) each use their own terminology in doing so. (This is just my own unpublished, unpublishable, unreliable take on this. You and others are much better-read about this subject than I am.) One way out may be to take the best modern encyclopedic treatment of the subject (I don't know which one that would be) and use its terminology consistently.—Finell 18:08, 30 December 2009 (UTC)

The reduction of astronomy to "Saving the appearances" was advocated by some ancient philosophers (Simplicius was apparently the first) and more recently by physicist / philosopher / historian Pierre Duhem. That's pretty much what I learned in grad school and until recently this approach dominated the historical study of ancient astronomy. However, recent investigations have found increasing evidence that ancient and medieval astronomers had strong commitments to the reality of their models. It was more than a patchwork of fixes.

On a related matter, in the past few days I came across a number of recent articles on the celestial spheres and reviews of a recent two volume study by Michel-Pierre Lerner, Le monde des sphères: Tome 1, Genèse et triomphe d'une représentation cosmique; Tome 2, La fin du cosmos classique. When we add to that Grant's Planets, Stars and Orbs, which is cited frequently here, it seems that there's been a lot of historical work on this topic in the last decade or so.

I think you're right on the issue of terminology; there doesn't seem to be a historically legitimate way to make it neat. Most historical and modern writers use spheres and orbs pretty indiscriminately as synonyms. --SteveMcCluskey (talk) 03:30, 31 December 2009 (UTC)

I did not mean to imply that pre-modern astronomers did not believe in the physical reality of their models, or that they thought that "saving the appearances" employed artificial means. They believed that perfect circles must be real on philosophical grounds, and therefore invented devices (epicycles and equants) to retain perfect circles while "saving the appearances" (i.e., conforming to observations). Copernicus appears to have believed in his model, yet he wrote of the importance of "saving the appearances". Even Kepler, the last great astronomer who was also an astrologer, also tried unsuccessfully to make a model based on the traditional concentric spheres that fit improved observations (i.e., that "saved the appearances"), and also tried some other mysticism-based arrangements, until he went modern, discarded the historical and mystical baggage, and worked out his three laws. Kepler is the bridge from the Middle Ages to the Age of Enlightenment, with big assists from Galileo and Newton.—Finell 06:15, 31 December 2009 (UTC)

Dab page in hatnote

There are other possibilities that readers who search for "Celestial spheres" might actually be looking for in addition to Celestial sphere. They might be looking for any number of Sky objects such as Celestial objects, Celestial bodies and Astronomical objects. In addition, they might actually want to peruse the article on the Celestial coordinate system, and for all we know, readers might even be thinking about the Celestial kingdom. As editors, we are not mind readers and can never truly anticipate what readers might be looking for. But we can work toward making things less confusing for readers, and to make what they might be looking for as available to them as possible. And that is the sole purpose of the dab page.

The hatnote could be shortened if other editors agree that it is too long. We might try something like this:

This article is about material celestial spheres from Antiquity to the Renaissance. For other uses, see Celestial sphere and Celestial (disambiguation).

or perhaps even:

This article is about material celestial spheres from Antiquity to the Renaissance. For other uses, see Celestial (disambiguation).

 —  Paine (Ellsworth's Climax)  16:49, 25 June 2010 (UTC)

GA Review

This review is transcluded from Talk:Celestial spheres/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: James McBride (talk · contribs) 18:26, 5 May 2012 (UTC)

Content improvements:

• I think the article could use a little coverage of why the planets and stars were all set in celestial spheres in the first place. The article goes in to great detail about the some of the mechanisms of how the celestial spheres of various models operate, but does not provide much explanation, even generally, about what these models were trying to do. For instance, the article mentions that some historians consider Eudoxus's model to be purely mathematical, but others argue that he considered it to be physically real. Some general discussion of this mathematical vs. physically real topic before getting in to model details would be good, if possible. Discussion of the predictive power of models would also be good.
  • Working on this; I've given a start on the influence of these models for establishing the distance of the planets.SteveMcCluskey (talk) 16:24, 8 May 2012 (UTC)
• Is there any possibility of images for more of the models? I had a very difficult time visualizing many of the descriptions.
  • I can't find any public domain images of the earlier models. I, too, wish there was a good image of Eudoxus's model (there's a not very helpful diagram of his model on the Russian Wikipedia).SteveMcCluskey (talk) 16:24, 8 May 2012 (UTC)
• It looks like the article on Dynamic of the celestial spheres includes coverage on pre-Middle Ages topics, yet it is included as a sub-section of Middle Ages in this article. Some reorganization may be needed.
  • For the moment, I've moved it to an independent sub-section in the history section (still located between Middle Ages and Renaissance). Three other options would be to:
    • Move it to the end of the history section.
    • Make it as an independent section after the history section (but it would be an awfully small section.)
    • Make a more radical change and restore the Dynamics of the Celestial Spheres article as a major section of this article. I think such a large change would not be a good idea. SteveMcCluskey (talk) 21:10, 6 May 2012 (UTC)
      • I agree that restoring the Dynamics of the Celestial Spheres article is not the best idea. I guess where it is now is better. James McBride (talk) 05:19, 7 May 2012 (UTC)
        • OK, I'll leave it there.SteveMcCluskey (talk) 16:24, 8 May 2012 (UTC)
          • It seems to now be a sub-subsection of "Philosophical and ideological discussions", itself a sub-section of "Middle Ages". Since the discussion of dynamics almost seems to run parallel to the many of the other topics discussed in the article, maybe it just should not have a section at all. Instead, the very top of the history section could link to the dynamics article, and a sentence on dynamics could be part of the relevant subsections of the history section. In fact, some of that discussion already happens. I'm not really sure what to do, but with the other re-writing and re-organization you have done, the dynamics section once again feels out of place. James McBride (talk) 23:32, 8 May 2012 (UTC)
            • I've taken your advice, put a new hatnote, integrated the text into the medieval philosophical section and removed allusions to renaissance dynamics. There's already a brief discussion of Ancient Aristorelian dynamics. SteveMcCluskey (talk) 16:17, 10 May 2012 (UTC)
• How important were these celestial sphere models? Are they something that only astronomers were concerned with? Or were Greeks (and later groups) generally aware of and interested in the models?
  • Touched on this briefly in the context of the size of the planetary spheres; probably a wrap-up belongs in the lede.SteveMcCluskey (talk) 16:24, 8 May 2012 (UTC)
• The content in the lead does not seem totally representative of the content in the body. For example, the lead includes a calculation that made use of the spheres, but no mention of this is made in the body, nor is there discussion of how accurate the models are. The lead would also be a good place to include some of the more general elements of the models that I mentioned above (the purposes they had, their level of importance), but I do not think it should necessarily get in to a detailed discussion of the order of the planets in spheres in different models.
  • Thanks for drawing attention to the role of these models for determining the distances of the planetary spheres. I've made a start of adding these to the narrative and begun to deal with the question of accuracy in computing planetary positions. General comments of the accuracy (or lack of it) of the various versions of these models still need to be added. SteveMcCluskey (talk) 02:42, 7 May 2012 (UTC)
    • I've tidied up the lede somewhat by moving the discussion of the emergence of the concept of celestial spheres to the historical section. I then broke the ancient section into two parts (before and after Eudoxus's spherical model.SteveMcCluskey (talk) 16:24, 8 May 2012 (UTC)
      • Now that you have introduced more discussion of distances, it is probably worth contrasting this briefly with modern, accepted values. That is, mentioning that the stars are in fact not all on a sphere, and have a wide range of distances, all much greater than that estimated by the celestial sphere models. For instance, the sentence in the lead "scholars calculated what become generally accepted values for the distance to the edge of the universe ranging from 65 to 75 million miles" does not make clear who these values were accepted by, and noting that the models converged on that value, but that it was a wild underestimate of the true distance to stars, is worth saying. James McBride (talk) 23:32, 8 May 2012 (UTC)
        • Added brief mention of modern distances, citing appropriate historical discussions.SteveMcCluskey (talk) 16:17, 10 May 2012 (UTC)

Minor points:

• The description of one of the models in terms of the space station in 2001 should be modified. That does not mean anything to me, and I would assume the same is true of others who might read this article.
  • Deleted the 2001 passage; the author shows his age. SteveMcCluskey (talk) 20:20, 6 May 2012 (UTC)
• The capitalization of Moon and Sun is not entirely consistent.
  • Upper cased them consistently. SteveMcCluskey (talk) 20:31, 6 May 2012 (UTC)
• Not sure what is going on in the sentence: "However instead of bands Plato's student Eudoxus then developed a planetary model using concentric spheres for all the planets, with three spheres each for his models of the Moon and the Sun and four each for the models of the other five planets, thus making 27 spheres in all ' " — is this just a formatting error?
  • Quite right -- the correct number is 26. SteveMcCluskey (talk) 20:20, 6 May 2012 (UTC)
• There is still a citation needed tag that needs to be resolved.
  • Fixed. SteveMcCluskey (talk) 16:24, 8 May 2012 (UTC)
• "Since Grant has been unable..." briefly confused me, before remembering there was a scholar named Edward Grant mentioned once before. He should be reintroduced here.
  • Revised. SteveMcCluskey (talk) 16:24, 8 May 2012 (UTC)

• I think the following sentence may need a citation: "Anaximenes may have been the first to distinguish the planets from the fixed stars in respect of their irregular movements."
  • It seems to be from Heath, but it's also off topic, so I've deleted the sentence. SteveMcCluskey (talk) 16:17, 10 May 2012 (UTC)

Overall:

Pass/Fail:

I think this can reach GA status, but it could take a moderate amount of work. It is well sourced and does not have any major problems, but I do not think it quite meets the standard of broad coverage yet, for the reasons outlined in the points above. James McBride (talk) 18:26, 5 May 2012 (UTC)

Thanks for the good comments; I'll attack them as time allows. I'll start with the easy ones while I think over the more substantive issues. --SteveMcCluskey (talk) 20:31, 6 May 2012 (UTC)

Overall, this is looking pretty good. I responded to a couple of your changes with further suggestions, and added one sentence that I think could use citation. This is now very close to GA status, I think. James McBride (talk) 23:32, 8 May 2012 (UTC)

Thanks for the effort of looking this over; glad you like it. SteveMcCluskey (talk) 16:17, 10 May 2012 (UTC)

I gave the article one more thorough read through. I'm going to go ahead and pass the article, as I think it meets the standards for a good article. If you are interested in improving the article further, I think there areas where the prose could still be made clearer. In particular, there are some sentences in model descriptions that are probably a bit too long. The sections describing the models of Anaximander and Adud al-Din al-Iji are good examples of this. Nevertheless, this seems to be of high enough overall quality to meet the criteria. James McBride (talk) 07:21, 11 May 2012 (UTC)

RE: a reproduction of Peter Apian's Celestial Spheres diagram

Hello,

I recreated Apian's Celestial Spheres diagram and uploaded it to wikimedia. It clears up the original a bit and makes the text and various divisions more distinct. Any interest in adding it to the page? — Preceding unsigned comment added by Cipozy (talk • contribs) 01:55, 1 October 2015 (UTC)

Thanks for creating a nice modern interpretation of the Apianus diagram, which must have involved a lot of work. However, for a historical article like this, I think the original woodcut is more appropriate. --SteveMcCluskey (talk) 18:25, 1 October 2015 (UTC)

Alright, I thought that might be the case. I'll only leave it on Wikimedia then. --Cipozy (talk) 15:13, 4 October 2015 (UTC)

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Chinese astronomy

The celestial sphere model mentioned in that article links here, but here I find no mention of it. It'd be nice if somone could rectify that omission and make Wikipedia less culturally biased. Thank you! 2A02:8109:1040:1724:B116:3D31:32C9:411B (talk) 15:23, 21 December 2018 (UTC)

Good point; parallels to the Greek model of celestial spheres in other cultures should be included in this article. However, Chinese cosmological models have not been as extensively studied as Greek models and it is hard to find good documentation on them. The discussion of the Chinese Celestial Sphere Cosmology, associated with the Hun Tian school, cites an article by Joseph Needham and Colin Ronan in Hetherington's Encyclopedia of Cosmology (1993). That article's discussion of this cosmology is really quite sketchy, pointing out similarities to Greek models, and hinting at possible influence. Geoffrey Lloyd suggests (Adversaries and Authorities, (1996), pp. 162-3) that Chinese cosmologies were "closely tied to observational techniques … and they are better considered not so much as cosmological theories, as rather ways of doing astronomy." Lloyd never addresses possible Greek influences on Chinese cosmological models, and seems to treat the Chinese model as an independent development.

Further investigation into the published sources is called for before the Chinese Celestial Sphere Cosmology can find a place in this article. Please feel free to dig into the literature and make additions. --SteveMcCluskey (talk) 21:56, 21 December 2018 (UTC)