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Archive 1Archive 2

May 2003

This was moved from user talk page and should stay here since it is interesting:

XJ, on the Hipparchus page: I am User_talk:Tom Peters. I was displeased to find that you undid much of my late-night edit job of yesterday. You re-inserted much of your previous text. I had removed that for a reason: either off-topic, obscure (language problems), factual error, otherwise misleading, or repetitive.

> OK, let me reply in brief. I am at first glad that you've corrected my clumsy English, but you must consider that the language is not my native. I did my best. And secondly I by no means did not want to destroy your work. I wonder if all these your arguments can be valid since we know so little about ancient astronomy, etc. The article as it was before your editings, please note this, stole me a lot of time too.

I came upon the subject because I wanted to find a place for some text on the traditional value of the synodic month (as known from Ptolemy and also still used in the Jewish calendar): it is attributed to Kidinnu and|or Hipparchos. I noticed so many flaws in the current page that I felt compelled to improve it. I can understand that you like to edit my contributions too, but I find the fact that you revert it to the original flawed text very unmotivating. Can we work together on this page or do you prefer to keep it for yourself?

> Yes we can do this together of course. I am very interested in this subject for quite a long time. And if you check the previous article I guess it wasn't so bad as you say it was. Just check it carefuly. And BTW I am also glad that you won't be anonimous any more.

My major gripes:

  • The formula for the logarithmic magnitude scale is off-topic in an article on Hipparchos. That modern scale was introduced 2000 years after he died. I replaced it with a reference to a Wikipedia page that adequately discusses these details. As a general comment, there is no need to elaborate on the whole history of astronomy on this particular page. I propose some more pruning.
> I can't see why one pretty simple formula is such a problem. Look around to other articles how many formulas (off topic) are there here. You can start throwing them out, too, he, he. I've put strictly some words about magnitudes just to show the importance of a work of this great astronomer, man. I am not trying to coment all the astronomy either.
> Tom replies (31 May 2003): I find this so misplaced as to be unacceptable. We can safely assume that Hipparchos never proposed or even thought about such a formula, so it is very misleading to give it such a prominent place on a page dedicated to his work. This is a much later development of a concept he started, and is properly discussed on the subject page Apparent magnitude itself.
> As I have said that is just your personal view what is unacceptable. I still insist that some more words about star brightness can not be harmful. Look to the history of page -- no one had any objections about some additional words, just you.
> Don't bring the "silent majority supports me" argument. It is not just a few additional words; my criticism (see above) still stand.
  • You quote year lengths etc. in so many decimals and in so many h/m/s . Hipparchos very definately never provided values in decimals. For historical interest, provide the value that he actually (may have) deduced, and give a proper value in modern decimal notation between parenthesis. Case in point, I did that for the tropical year. Hipparchos found that the real tropical year was shorter than the then-traditional value of 365 and 1/4 of a day, by about 1/300 of a day. Not x days, hours, minutes, seconds; not x decimals. That is what he found, and that is what I wrote. By specifying so many days and decimals you misrepresent his contribution.

Incidentally, the vernal equinox year in solar days at that time was about 365.2423 days, not 365.24219... like you insist. See my page on the Tropical year or http://www.hermetic.ch/cal_stud/cassidy/err_trop.htm

> I did not put those numbers without any calculating just do not think so. How can you be shure that 'your' values are correct. Just think in this way. If I put one or several superfluous decimals in a calculation I won't do so huge error. Hipparchus calculated (this is my opinion) mostly by means of hours, minutes, ..., so that is why. And if my opinion is incorrect this way od stating these values can also be in text for comparisons with other values. Which 'Martian' formula did you use for the value of the tropical year at that time? Yes you can go back to history and use one general formula and here we go. My values (they can be wrong too of course) are here because they have appeared in many other sources. And I am going to check your URL also. I won't check your recent corrections until we can find some way out. This takes time and hard work. At least to me.
> Tom Peters replies 31 May 2003: The original sources I have on Hipparchos are translations of the Almagest and the Naturalis Historia. Ptolemy states that Hipparchos found a correction to the tropical year of 1/300 day. You quote 2 values from different sources: one is a value expressed in decimals but apparently derived from the value rounded to minutes, the other is the value expressed to the second. You twice use the "=" sign erroneously, because 365.24653 d is not 365d5h55m12s, and 365.24666 d is not 365d5h55m. But this illustrates my point: by expressing Hipparchos' value in other units you introduce some rounding, and these values go live a life on their own, get converted again, etc.: and you end up with a mess.
> As for the actual length of the tropical year as Hippachos could have measured it: that can be computed to a known level of accuracy by fitting our modern mathemetical models to modern observations, and then compute backwards to Hipparchos' time. Anyway the value of 365.24219... that you quote is valid for a definition of the tropical year in 1900, but not in Hipparchos' time!
> Ptolemy is believed to be quite inaccurate, so Almagest is probably bad source for studing of Hipparchus contributions to science. And Strabo also. Strabo is also stated somewhere in Wikipedia as an unreliable. 365.24219 is not my allegation. I have just copied it. And how can we check it out now? You say it is valid for 1900.0. According to which equation? I do believe that Hipparchus was measuring with precision up to seconds -- but you say this is not true. I can't prove my statements right now, but if you give me some more time, I'd be glad to. Are those models reliable?
> Ptolemy may be inaccurate, but that is a non-argument. He is the best source we have for Hipparchos' work. You take two separate sets of values from unspecified sources, fail to recognise that one is a rounded value of the other, and confuse things even more by assigning the rounded d:h:m value to the preciser decimal value, and the full-accuracy d:h:m:s value to the decimal equivalent of the rounded value; and even when I show this to you, you fail to notice that there is a problem. Give me a break!
> As to the precision of Hipparchos' measurements: we agree that he used only simple, and therefore inaccurate, instruments. Ptolemy estimates that his equinox observations could not be more accurate than 1/4 day - and in fact his own computations for the events Hipparchos observed show discrepancies of that size. Given the time span of 300 years for the observations (and considering that the earlier observations are even more inaccurate), Hipparchos could derive a value with no higher accuracy than maybe a minute. So what makes you believe he could reach an accuracy of a second?
> And we can really achieve better accuracy today. Read the page tropical_year and some astronomical literature, OK?
  • You tend to assign a variable name to constants you mention. What is the point? You do not refer to these variables elsewhere, and those variable names are not at all standard in other literature either. They only confuse the text, so I removed them.
> A point? Simple. Tropical year is in astronomy 'usually' designated as (how strange) T and so on. Indexes are simply related to authors. That is just my way of writting things out. If you don't like them, don't teach me that I am doing wrong, because I'm not. Just leave them out if you wish. But in your way reading one technical text is harder. At least to me... Do I have to refer to them? Just wait for the table of other values and you'll see. Or to bring up some old Hoyle's calculations.
> Tom replies 31 May 2003: I am very knowledgeable in astronomy and ephemeris calculations, and I contest that T is a usual designation of the tropical year. T is mostly used in this context for a period of time expressed in Julian centuries. But that is besides the point. In a text you can assign variable names as you like, as long as you are consistent. But in this case they are not used at all, and therefore they are superfluous. You are suggesting the existence of some external standard nomenclature and references to this value that are not actually present. We just want to state that Hipparchos found this particular value for the tropical year (or whatever). By also assigning some arbitrary variable name to them, you are confusing that simple message.
> What to say more? You've said it all.
  • The subject matter is scattered all over the page, and also there are many repetitions. Details pertinent to the tropical year or the star catalogue pop up in 3 or 4 places. I tried to collect all that (for the tropical year initially), but you bluntly re-inserted your original pieces without improving on this point - why?
> Look at the structure of the article, please. I've partly repeated some yes but not much. The meaning of Hipparchus' star catalouge is important for the discovery of the precession. If I am going to write what Hipparchus also did on star constellations I'll also have te repeat again. You can't say your order of sentences is better. I have also think on that and they are not just scattered as you say.
> Tom Peters replies 31 May 2003: I did see the article and I found the structure flawed. I must add that I do endorse your insertion of section headers. But consider the material presented on the tropical year (what is what I first concentrated on): first you mention solstice observations by Meton and Euctemon; then Hipparchos' equinox observations; then Archimedes' observations (BTW are you sure Archimedes made such observations and Hipparchos used them? Thusfar I did not found references to them in the Almagest). Then you present H's results for the tropical year. Then follows the section on the excentricity of the earth's orbit. Later you mention the way he did his observations and that he derived the tropical year, then you attribute a value for the siderial year to him, then you mention the solstice observations by Aristarchus (relevant for the tropical year but not the sidereal), and then Meton and Euctemon again. This is a mess!
> Moreover, the drift of your story (as far as I can follow it) is that H. discovered precession from the difference between the sidereal and tropical year. What are your sources for that? I did not see Ptolemy attribute a value for the sidereal year to Hipparchos. Instead he mentioned that H. measured the distance of Spica from the equinox during an eclipse near that equinox, compared that with similar earlier observations, and found an unexplained difference.
> Who says that that mess didn't actually happen. I confess that a story is a little bit confused but to be a complete mess. If you have a better story go for it. I am not sure about anything regarding Hipparchus work and life and so I can't be sure about Archimedes' observations either. This is also a copy from other sources. I can't give you them at the moment. I can't confirm also 'a story' about Spica's measurements. Everything is just a reconstruction and everything that you will change or erase in a good faith will still be a reconstruction. Many sources mention he was aware about the difference between the tropical and sidereal year. This is not my invention. But I do believe it. Otherwise Hipparchus would not be so important as an astronomer.
  • I believe we at least agree that the english language of the page can be improved. So why then replace my re-formulations by broken English? What is " almost basic astronomical instruments" supposed to mean? Or the phrase "After that from 141 B.C. to 126 B.C. mostly on the island of Rhodes, again in Alexandria and in Siracuse, and around 130 B.C. in Babylon, during which period he made a lot of precise and lasting observations."

A tip: do learn to use articles ("the", "a"). The text sounds so foreign or telegram-like without.

>I understand a "basic astronomical instrument" as gnomon, and such. Not some telescope with complicated mountings... But you can change this or leave this out. Let me then put in this way. Hipparchus as it seems was observing at four or five different places. The text sounds so foreign because it was translated by foreigner. If you don't appreciate works of other non-English Wikipedians, than do not allow them to edit here. I am doing my best and by some other Wikipedians I wasn't so blamed. Some of them even encourage me to contribute. Yes I know for my bad usage of articles. Sorry. Now I think I know something and then I see I don't.
> Tom replies 31 May 2003: I do not have an issue with you writing imperfect English, but I do have an issue with you replacing good English by bad English. Just one example: almost basic ... What do you mean? "almost" is an adverb to the adjective "basic". So you mean to imply that these instruments are not really basic? Do you mean to imply then that these instruments are somewhat more complex, or do you mean something else? Why should we care about such nuances? Even if you do, there are more proper English ways of saying that - that's why I reformulated that sentence.
> Bad English does bother you. Otherwise you won't say nothing. Perhaps I should say in this way: Hipparchuss mostly used basic astronomical instruments. Almost is not connected with basic. A pure mistake. Instruments are basic, yes, of course. It is easy for you to say that there are 1000 more proper ways to say something in English. I am a foreigner and as you can see it is still hard for me after all of those years studing English language with a great joy. But I won't here defend my knowledge or ignorance of this beautiful language.
  • I propose to rename the page to "Hipparchos", which is a more decent transcription of his original Greek name, rather than use his latinized name "Hipparchus". Unless there is a Wikipedia convention or policy on transcribing non-English names that says we should stick to the Latin version, but I have not found any.
>I've seen mostly Hipparchus. You can rename it if you wish. I do not care much how is he named in English. But I would like to know. It is time already for that. In my native he is called "Hiparh". I hope this reply will make things more clearer. And again I really do not want to spoil others work. And finally let me say I am also doing quite some time on a portrait of Hipparchus but I am afraid it won't be accepted as I want, so I haven't posted it yet. I have some bad experiences with my portait of Copernicus. (See for example at: http://www.3delavnica.com/index.php?main=galerija_image&oddelek_id=2&image_id=3869 ) I would also like to make some technical drawings regarding the subject from such articles. I can send you one of sketches of the Hipparchus portait for your inspection or opinion, too. And as I've said I won't change any of your words or values until I reach minimal consensus. Best regard.
> Like I said, what is the current practice or policy in Wikipedia? Personally I dislike using latinized or anglicized (Ptolemy !) names and prefer a transcription of the greek names.

--XJamRastafire 22:13 30 May 2003 (UTC)

Dear Tom Peters, just tell which things should be improved and I am willing to change them all including strictly your original words. Do not bother to correct an article again in a whole. Just say what do you think is not right. Best regards. --XJamRastafire 22:21 30 May 2003 (UTC)

> Tom replies 31 May: That I consider not "Wiki". First of all I find it very tedious to elaborately explain what exactly I like to change, when I can actually do it myself in much less time. Second even if you started it you don't own the page. I just want to avoid that we end up in repeated cycles of removing each others edits.
> If you are sure what you are doing that is your problem. But as Google gives me about 12,100 entries for Hipparchus and 'just' 2,830 for a Greek version of his name I do believe that the first name is more correct in English. But I am not an expert about English. If you believe that you can do all the work alone, you are wellcome to do so. I would prefer collaboration but I guess according to all of your 'intelligent' writtings this won't work. I never said that I have started that page. My first edit begins on 2002-03-18 at 21:06, so I can't own that page since it already existed some 7 months before. I just tried to give one serious contribution. You can nullify it entirely, you have every right for that. But I guess there must be some minimal culture in such acts. You have compeled me that I shall again examine all the values and the whole story about Hipparchus' contributions to the knowledge and discovery of the precession of equinoxes. And while you're at it, you can check also some values at Ulugh Beg page about sidereal year. The same thing as with Hipparchus. Just to save you time for browsing around Wikipedia.

Tom let us start in this way. I've put back again a statement of how an astrolabe came in Europe by Arabs. My sources say this happened in 10th century but you say in the article for the astrolabe that it happened in 14th century. What should be correct? You have 'probably' also correctly stated that this astronomical instrument was 'probably' discovered by Hipparchus. In fact we really do not know if this is true and even Carl Sagan can't help us much here with his virtual view on an ancient astronomy, right. But I like this kind of almost detective work about restoring let us say unknown astronomical knowledge of the past. I am also aware that some authors might very simply say that the discoverer of a precession is not Hipparchus at all. Some say this fact can be discovered just by means of horizon astronomy as 'perhaps' ancient Maya did on the other side of the world. I've tried to emphasize the opposite view that this final discovery was made within 15/16 or more years by this Greek astronomer. But this is still not a proof for that. Perhaps some other day in the near future. --XJamRastafire 22:46 30 May 2003 (UTC)

> Tom replies (31 May 2003 6:30 UT) on astrolabe: I did not insert the 14th cy: that already was on that page, and it mentions a 14-th century treatise. No doubt the astrolabe existed in Europe in the 10th cy or before, if only because there were important and developed islamic kingdoms in southern Spain and in Sicily. But on the current Hipparchus page you state that the Arabs improved the astrolabe in the 3th cy, not the 10th. In absence of a historical refence I find this hard to believe because the Arabs did nothing of lasting fame at that time: they came into the picture only after Mohammed in the 7th cy. But my main issue: it is misplaced to elaborate on the subsequent history of the astrolabe on the Hipparchus page. Use a link to the proper page!
> This is again your personal view what is superfluous and what is not. A reader has to look thereupon to new links although he could learn some brief facts at once. This is a good practice for one reader, but... I do believe that Arab astronomers were active already in 3rd century. But you need proof, right. I'll try to find some more sources to support this quotation. Some (or many) European scholars went to Arab countries before 10th or 14th centuries and perhaps they alone bring the knowledge of an astrolabe and not Arabs alone. One of historical point is a fall of Constantinople in 1453 to Ottoman Empire. Many Greek scholars, as we known, have run away from the city together with many scientific books. Perhaps that is why it is belived that astrolabe came to Europe in 14th century. --XJamRastafire 15:03 2 Jun 2003 (UTC)

June 2003

Tom Peters at 5-June-2003 16:30 UT
You still don't get the tropical year right. Between the parentheses (...) you still equate 365 + 1/4 - 1/300 = 365.24653...d = 365d 5h 55m . This is wrong, the value with fractions is equal to the values in front of the parentheses. It is fine if you round the value to 55m, but the rounded decimal value should be 365.247 or 365.2467, but not the precise equivalent of the value rounded to minutes. In other words, you first round to minutes, then give a precise number in decimals for that (rounded) value, and then put it first in the equation with the fractional value. And then it is wrong: 365.24653... = 365 + 1/4 - 1/288, not 1/300 like Hipparchos said.

>[XJ]: Yes, you're right. I've corrected this. I'll still try to figure it out if those 12m make any differences to show he was actually more precise...

I find your treatment of my refutation of that temple myth malicious. The fact that the Egyptians built temples 2000 B.C. does not give you the right to postulate that Kidinnu (or Hipparchos) used a temple of that age to find out about precession. Please quote some reliable source with specific details (like which temple, what star, what records to link that temple with that star) to validate that anybody actually noticed precession this way: otherwise I insist that this fable be removed from the page.
Besides, as I already pointed out, the sentence says that Kidinnu made observations of a temple. Astronomers do not make observations of temples. Also I do not believe that such a story has been told about Kidinnu: I believe that you read it on the page about precession, but there it is Hipparchos who studied temples. Of course this confusion is just due to the level of your skills in writing English, which I do not hold against you: but I do find it incredibly stubborn that you do not correct the errors when someone takes the trouble to spell them out to you.

>[XJ]: Hey man I am not malicious at all. How can you be so presumptuous. I've just corrected your saying that these temples were not built before 2000 B.C. If there is some truth about this particular temple it is not my mistake that I still stand on what was written in wikipedia. But if I think further on. As Hipparchus spent some time (or probably most of his time) in Alexandria he might have seen a temple alone. And probably he spoke to 'priests' or 'scientists' there. I know that someone do not observe temple but he study it. I do not have to know English to comprehend this. You did not uderstand my sentence. I enumerated three sources which might helped Hipparchus to define and notice his discovery:
1. Observations of Timocharis and Aristyllus,
2. Records of Chaldean astronomers and specially Kidinnu's records,
3. Observations made in a temple of Thebes. Some observations must have been carried out since it is oriented, as was claimed, to Spica. We can't deny this fact.
TP: yes we can deny this and I do. What facts? I see none. Which temple? When built? Oriented to Spica - what does that mean and how would that work? Who noticed that things changed? Even if the temple does not exist anymore, there should at least be a text that mentions these facts. For lack of that, there are no facts but only a story that Hipparchos investigated some temple in Thebes of impossible antiquity and discovered precession: nothing on what he found or how he reached his conclusions.
And for good measure: Ptolemy explains how Hipparchos discovered precession. I did read nothing there about temples. P. lists H's dated observations - which we can validate with modern ephemerides -, we can follow his reasoning and understand his conclusions.
So your 3rd hint for what could have helped H. is far inferior to the first two.
I have no time or authorities (aka sources) to check this on the spot. We can also deny that Greenwich is not aligned to the 1st meridian in this manner. (Or perhaps studies of that temple made by Hipparchus himself).
I was not precise with my expressions, true. I do not fall in a classic archaeoastronomical 'sham' that one building is oriented to this and that celestial object, etc. How can I give you any source? I would give you that if I knew some. So... I would make a table of all 850 stars in Hipparchus catalogue if this would help, yes. I vote that this sentence still remains in the article just to give a clue what Hipparchus might had for his discovery.
TP: First of all, the source that I think you used (precession) claimed it was Hipparchus who studied a temple. You rephrased that and put it together with some other info, and all of a sudden this page says that it was Kidinnu who did that. Just because of poor syntax the facts of the story change. So what this page says is your invention and not historical fact, and I really think that you should re-write the section with the things we know.
>[XJ]: Look! I did not rephrased what you say. I've explained above. It does not come from my changed text that Kiddinu was at Thebes.
>[TP] You put that sentence there a week ago (30 May). So can you please tell me what your source was that says that Kidinnu studied a temple from 3200 B.C. at Thebes, and may have drawn some conclusions about precession? For I read exactly that same story on the page about precession, but there it involved Hipparchos, not Kidinnu.
> Kiddinu perhaps never leave Sippar or Babylon, since Babylonians were cruel nation and I guess their scientists were not able to wander around as free Greeks might be. Or I do not understand English at all or what? Perhaps that temple was (or is still) oriented towards Spica for one passage of that meridian. I do not know. But it is possible. So from here Hipparchus might get some data. I did not say on any place that he had just discovered precession in a minute. Perhaps he studied it his whole life. Perhaps I shall tommorow hear on the Discovery channel that a temple of Thebes was oriented to Spica as Orion reoresents Milky Way in the sky and such. Perhaps I must start to learn gibberish and stop writing in English. We yadd ... --XJamRastafire 14:39 6 Jun 2003 (UTC)
>[XJ]:Addition 1: If we treat internet as a modern Almagest as a source of an ancient astronomy and if I read there that Hipparchus believed that there are total of just around 3000 stars in the sky. Can I write this here in wikipedia? This claim together with a temple of Thebes is interesting for me, since it gives me some clues. But they are all inferior as you say. I am not Delambre or a worldwide known expert for the history of astronomy. You should esteem this. You're just sully everything that does not suit you. You may have thousand Ph.D.s. We can at least agree that something is still missing in this story. Or not? What star? What place? Do you believe that everything that is written about Hipparchus is all? I can't. Or we credit him too much inventions. I am mixed up a bit now. I would like the article to be consistent and as it seems I'll just have to delete all according to your 'strong' arguments. I won't. You have already started new article, which is more correct than this one. Go ahead. You can delete this one and ignore my preposterousness. But look around and check if you can find better encyclopedic article about Hipparchus. I think it already has strong structure which might in the end be close to the truth. I am still waiting for the silent majority. As Einstein said one sentence can disprove a theory while 100 sentences can not prove it... (or something like that).
I have concentrated to his (probably) genuine discovery, but you have already simply dispersed all arguments to the separate sections. The story as you've argued is really confused. I have to do some more work on it. But on the other hand we must not look in full with today's eyes. I mean on what was discovered first, what influenced on other and such. I am not stubborn, I try to think on what someone said. I hope that 'stubborn' do not mean 'impenitent'. And if I am trully stubborn, you must be a Mr. Know-all, ha, ha. Some horse-laugh won't harm... You also must be sure that those are really errors.
TP: No, we must be sure these are really accurate facts. It is no so that any story is true until proven false.
Now back to hard work that the article becomes even more satisfying :-) Respect. --XJamRastafire 18:46 5 Jun 2003 (UTC)

Tom Peters ate 5-June-2003 02:30 UT
XJ: I see that you liked at least some of my edits and put them onto the Hipparcus page. I see you also reverted back some of my changes: however I did not make these without good reason. Let me explain:

>[XJ]: I like all the positive critics from anyone as long as it is constructive. I think that you are doing some injustice to me since you're equating all possible errors in this or other pages with the whole subject. But I still hope we'll find the way out.
  • The older as well as the latest text state that Hipparchus was born in Antigoneia, and that the city was later, in 30 (A.D.?) renamed to (greek) Nikaia or (latin) Nicaea by one "Cisimah". Apart from the fact that it is off-topic on a page about a person to discuss the names his birthplace may have had throughout history, I believe that information is wrong. The Wikipedia page on Nicaea tells that Antigoneia was renamed to Nikaia by one Lysimachos already in 301 B.C.: so I suspect a scribal error in the year. In addition, I cannot find anything about this "Cisimah" in my encyclopedias, and Google turns up only this Wikipedia page. I wonder if "Cisimah" is a Turkish adulteration of Lysimachos. Anyway, I believe that the town was called Nikaia at the time that Hipparchos was born there, so the erroneous details from dubious sources on the names of the city are best removed from this page.
>[XJ]: I stand with the view (as I've already written multiple times) that some supplementary words are not harmful. But not all over. In this case I have put some more information about Hipparchus (or Hipparchos) birthplace since it is somehow strange (at least to me) that one Greek is born somewhere in Asia Minor. We have to know some history since ancient Greece was 'stretched' to the present Turkish territory. "Cisimah" must definitely have been a person with the more proper name Lysimachus. I haven't checked the wikipedia article about Nicaea and at the time I was translating the text I haven't found proper English or Greek name for him. About the years 30 or 301 BC. As I remember this is not a typo. It must be an error in that source. But perhaps it is correct after all. So I have formulated a sentence in this manner. Nothing wrong (except the name) if a year 30 (AD) is correct, otherwise absolutely not. Perhaps Lysimachus is also a mith as temple of Thebes is (for you). I really do not know. Do not blame me for all, please. And again. How strange is for me that English uses more Latinized words than original Greek ones. If we stick to your proposal then Hipparchos and Nikaia must prevail. I just follow to the more widely accepted terms.
  • The section on "Geometry and trigonometry" starts with the phrase: "It is thought that Hipparchus compiled the first catalog of stars". This clearly is out of place, so I removed it from my text. You edited this section, why do you keep this sentence? It doesn't make any sense!
>[XJ]:I guess this is because one source didn't know much about Hipparchus contributions to catalogues. I have checked many sentences but since they are from many different sources some contradictions may happen. I am glad that someone notice this.
  • You still do not seem to understand the issue about the tropical year, so I will try explain once more.

You write: TH = 365.24653...d = 365d 5h 55m 12s
WRONG: ________ 365.24653...d = 365d 5h 55m 00s !
and:
______ ________ 365.24666...d = 365d 5h 55m
WRONG: ________ 365.24666...d = 365d 5h 55m 12s !
You religiously stick to 2 sets of values from different sources, but swapped the decimal and sexagesimal values.
Like I already described in detail, Hipparchos found a value for the tropical year of 365 + 1/4 - 1/300 days. This is 365.2466...d decimal, or 365d 5h 55m 12s exactly. However, if you specify a value down to seconds, you insinuate that the error is less than 1 second. But, as I have demonstrated, the accuracy of Hipparchos' value was worse than a minute. So if you express Hipparchos' value in d:h:m, then it would be rounded to 365d 5h 55m; that gives the decimal value 365.2465277..d . So the two sets of values that you so stubbornly keep quoting are really the same, but one is properly rounded while the other represents the actual value from Hipparchos but with a false sense of precision.
That is why I insist that the proper text should be something like:
"From all these observations he found that the tropical year had a length of: 365 + 1/4 - 1/300 days (365.2466... d = 365d 5h 55m)."
The "actual" value that you quote for the tropical year is a rounded value for the mean tropical year valid for the present (rather than 1900 like I wrote earlier). From modern ephemerides like the VSOP-87, which are sufficiently accurate for thousands of years, we can compute that the mean tropical year at 150 B.C. was about 365.24232 SI days; taking account of the fact that the length of day at that time was about 34 ms shorter than the SI day (see [Delta-T]]), Hipparchos would have found a mean tropical year of 365.2425 of his contemporary mean solar days. However, the vernal equinox year was about 365.2423 contemporary mean solar days (see [tropical_year]] for an explanation of the difference). Anyway, the difference with Hipparchos' value is about 6 or 7 minutes; again it is pointless to specify it with a fake accuracy of seconds.

>[XJ]: I did understand you perfectly. First I've seen alone that above two first values are swaped between. OK. You 'religiously' state (as you've said Ptolemy's claim from Almagest) Hipparchus value of "ty" with a correction of -1/300 day. I didn't insinuate that. (Can you explain this? How can you conclude from what was written that the error is less than 1 second?). I just wrote his error is about 6m 27s or 7m roughly (6m in fact -- if we round to minutes). I am not sure that you're really able to define his precision. I am aware that we can easily state his value to be T_H[145.00 BC] = 365d + 1/4 - 1/300. We don't calculate in this way anymore. I tried to give comparisons. The same with "sy" to be S_H[134.00 BC] = 365d + 1/4 + 1/144. The difference is then S-T= +1/444d = +3.2m and not +1/72d = +20m as it should. (This must be checked! Where is an error -- in T or in S? ??) Again. These are not my values. I have transformed them from other sources. As you have seen that author have compared Hipparchus' value with the present one and not for the 200s BC. I can't make calculus if I do not know the exact value of T_H[145.00 BC]. I'll do some more calculations to persuade myself that -1/300 is OK. It sounds fine yes. But I still must show how Hipparchus was able to make values within seconds and not just in minutes. As Dennis W. Duke (Florida State University) showed that Delambre in his Histoire de l'Astronomie Ancienne (1817) concluded that Hipparchus knew and used a real celestial equatorial coordinate system, with the right ascension and declination. After that Neugebauer in his A History of Ancient Mathematical Astronomy rejected Delambre's claims...
  • An example of problematic English: "His star map was thoroughly modificated as late as 1000 years after 964 by A. Ali Sufi and 1500 years after 1437 by Ulugh Beg."

This means in the years 1964 and 2937 (A.D.). The phrase should read something like: "The star catalogue was updated more than a millennium later in 964 by A. Ali Sufi, and as late as 1437 by Ulugh Beg."

>[XJ]: I would put just "in" between "after" and "964". How can I know as a stranger that "to update" is more proper verb than "to modificate". You again generalize. Millenium later. I've written exactly 1000 years later and 1500 years later. This is just a matter of style and feeling. Your sentence sounds more poetically, mine more analytically. But you claim that mine is bad, obscure, problematic or whatever English. Just like my professor of Slovene.
  • You added the phrase ", the records of Chaldean astronomers and specially Kidinnu's records and observations of a temple in Thebes, Egypt that was built in around 3200 B.C.". This is confused bogus. It says that Kidinnu observed a temple in Thebes. Apparently you extracted this text from the page on precession, which said something similar about Hipparchus. I could write a lot about myths like this, but will state:

- neither the babylonian Kidinnu nor the greek Hipparchos would be particularly interested in egyptian temples;
- there were no temples in Thebes as early as 3200 B.C. (at least none that would survive into Hipparchus' time: the Egyptians started building in stone only about 2700 B.C., and the earliest surviving temples in Thebes|Luxor|Karnak date from the 11th dynasty, ca. 2000 B.C.);
- there is no astronomical information in the (orientation of) Egyptian temples that would have been of any use in the discovery of precession.

>[XJ]: Probably some Greek must have gone to Egypt. Chaldean and Greek astronomers helped sovereigns to build those temples so I guess they knew a lot of their geometry and meanings...

There are many such errors, confusions, and off-topic elaborations on this page. I find it too tedious to repeatedly write half a page of explanations whenever I change a number or erase a sentence. Please start thinking and consult good sources. One thing to consider: the less irrelevant data there are on the page, the fewer errors there can be.

>[XJ]: I am doing just that. But we all learn all the time, right. I'll try to consider all these your arguments and act according to them. The answer still remains. Did Hipparchus really discover precession? I deeply believe that, since Maya's Tzolkin (to include precession) is also very attractive to accept it. Thank you very much for your arguments anyway. They are more constructive than precedent ones, although they are still very aggressive. I have studied enough astronomy to understand "basic" concepts. But nothing is never enough. OK? Respect. --XJamRastafire 09:40 5 Jun 2003 (UTC)

Redirect to Hipparchos

I've decided to redirect this article to Hipparchos one. Since according to Tom Peters I am not able to contribute further on to this article, no alternative is left for me. Tom unless you have any other suggestions, please let me know. I have indeed learnt a lot from your arguments, but generally speaking they are too offensive for me. Best regards. --XJamRastafire 13:49 7 Jun 2003 (UTC)

July 2003

User:Jmccann
Thu Jul 10 20:15:15 GMT-7 2003

I began this article many moons ago (when Larry Sanger was still here, and the Wikipedia was young) and am pleased to see that it has been updated a great deal, yet still has a couple of my original sentences. I am not so pleased that it is a mess and that there is quite a bit of contention and wasted effort here. What is the deal w/ the Hipparchos page? I'd like to help clean this up, but don't wish to spend time on it if my changes will just be undone.

Dear Jmccann. Do not worry. Tom Peters is now working on (actually this article), but just on a different page (namely Hipparchos as he is not satisfied with this one. He made some nice contributions (and more accurate ones) so everything is just okay. Me and he had some 'edit wars' but now, I hope; this 'problem' is solved. The final article (as it is written above this article) will find place inhere as soon when some 'crazy' Wikipedians find minimal or 'maximal' consensus about it. I have also to say that I did not move any of your sentences, since I am not a native English speaker. I just have added some stuff, which then became an object of Tom's disputation. I also think that this will be a great article. It has to be. So none of your time will be lost. Best regards. --XJamRastafire 02:15 11 Jul 2003 (UTC)
I started "Hipparchos" as a scratch page, to gradually build an improved biography without further dismembering the "Hipparchus" page that now is mostly XJam's work. However, someone couldn't live with an alternative and redirected the scratch page, with some merge of content. So the thing now is really messy. I didn't want to take the trouble to revert everything back and decided to work on XJam's text top-down. I had been waiting for some scholarly literature, which is now in, so I started editing. My plans are:
  • Edit the text point for point, justifying my changes.
  • Stick to established facts, reduce speculations and clearly identify those as such.
  • Reduce excursions into later developments, provide links instead.
  • More thematic (and if possible chronological) buildup. Almost everything is under "precession" now. If I understand correctly XJam wished to give an account of what factors could have contributed to H's discovery of precession, but the text was unwieldy even before I entered. I suggest that XJam waits for my presentation of the material, and then rebuilds his case.
Of course I am meekly waiting. And once again - everything is under "precession" now - just because everything (or what will remain) influenced on this discovery. I can't help it. I suggest you also think about a different structure of an article, otherwise you'll spin around.
I did a major cleanup today on the year stuff before I read your note. Anyway, I believe the issues on his solar theory are sufficiently explained now (except on distance, which will follow). One reason why to split up things is that H. wrote his works on specific subjects (the biography by Toomer mentions all books attributed to him), and not one huge volume where everything leads to precession. Also to put everything he did in one huge paragraph does not provide a clear overview of his achievements. My strategy is to discuss the various topics he worked on, and then we can write a story how things relate to precession. I don't see how that gets me spinning around. -- Tom Peters 00:32, 20 Aug 2003 (UTC)
As things go, nothing will remain in the topic of precession. I suggest that when some (or everything) is resolved, we again have to repeat what is now scattered all around (or will be even more scattered...). But this is not a policy or strategy of the article as TP wants. (- My primary goal -, which was abandoned by TP). We also have to check or to wait some more 100 years to see what was known to Mayan astronomers (or to some others) about the horizon astronomy, possible knowledge of precession and so. Ptolemy, Teon, Strabo are (in my opinion) just some 'lazy bones', and how can we be so confident that everything they have written about H's work is really correct? TP - your numbers are magnificent, but I do not see the whole picture. Yet. Or now. What is H's greatest achievement in fact after all? According to the present text, of course. I deeply believe that (most probably) the discovery of precession. We have to know that this phenomenon was actually first depicted by Isaac Newton centuries after H lived. In fact astronomers were not able to do this on their own - I guess... TP showed that Chaldean astronomers knew what H was doing in astronomy (and not just vice versa) - this is very much astonishing (at least to me). I am also still surprised that so little has survived of H's original work. All of this debate will be in vain if we would know all his real works, but I see now how Hoyle was right. We must know that H's (H now for Hoyle) character was very curious - he was traveling in his jeep with his wife around the offroads of former Yugoslavia (as one Bosnian journalist once said), not to mention what he believed how life came to Earth) - |but who cares|. TP - my bad article (as you've saying all the time) was pure reconstruction with available sources. You are doing the same. With some more (more accurate) sources. (remember Burning Spear's song Bad to worse :-)). I'll give you a break now... --XJamRastafire 11:05, 21 Aug 2003 (UTC)
All this may take a while...
About the H's birthplace. Where again did you find that Nicaea is 'just' believed (a strong tradition) to be his birthplace. I can't understand that for instance we know "for sure" that Thales was born there and there, but when we come to H - this becomes almost impossible...
I suppose that for Hipparchus we are as sure as for other ancient philosophers. There is almost never a decent contemporary biography stating that he was born then and there. The usual distinctive of origin, like "of Alexandria" may as well refer to the place they lived and worked, as the place of birth. -- Tom Peters 00:32, 20 Aug 2003 (UTC)
-- Tom Peters 24 Jul 2003 9:17 (UTC)

August 2003

In response to XJamRastafire's complaint of 21 August:

  • Sorry it is taking so long. There is a lot of literature, but that and the original sources are hard to obtain.
  • Yes this way little will be left under precession. I keep it as last, because it is the most difficult part. Also it builds on many other things that H. did - so I find it much easier to discuss those components first in some detail, and then paint the grand picture, referring to the results discussed earlier. In the all-in-one story we drowned in details; for instance the solstice observation by Meton was discussed twice, one of which wrong, and all that is anathema to precession.
  • If you want to give an account of other civilizations anticipating precession, then I think a page on precession or history of precession would be the proper place. Similarly stuff about geodetic precession, which is relativity theory that has absolutely nothing whatsoever to do with Hipparchus. Please lets keep things on topic! In this case, Hipparchus.
Yes, I want for sure. I even want to fix things with H's work, of which you won't. But you're probably in one greater advantage. First of all, you own some Ph.D. in (how strange) chemistry (as I've seen on your user's page). I own just a college official knowledge (if this goes in this way). That's great that you have. And look on this, too. We all are different people... You are also one 'venomous' Dutch (who some centruries ago thought they were the rulers of the world - I mean because they were the great explorers and sailors, have one of the greatest navy - think on that my navy has at present just one boat... :-). I know this will sound strange. You have an access to some original works of Theon, Ptolemy. (Think again - there are no translations of Almagest in my native -- and as I've already said once I hadn't any English, Latin or Russian translations. Sure I would like to give some more additions, but again the story is the same. I'll never go to Yucatan - although I could go somehow, since there works one Slovene archaeoastronomer (namely Ivan Šprajc), who does have one Ph.D. in these fields. How a geodetic precession does not have anything with an Earth's precession? I think it has. The mechanism is in fact the same. As we know, we can write Newton's law for both, linear movement and for the rotation (bla, bla), where F in analogy is changed with M and so. That is one of the beauties of physics and other sciences... The symmetries, analogies and such stuff.
That is my point: geodetic precession has to do with precession, and should be discussed on a page dedicated to that subject. This page is about Hipparchus, who had to do with precession, but the general relativity stuff came 2000 years later - totally off-topic here. As I argued before, we should not discuss all of the history of astronomy on this page. Maybe some things to clarify H's work in the light of todays knowledge, and his immediate predecessors and uccessors. Tom Peters 13:17, 28 Aug 2003 (UTC)
And I do not understand you quite what you've said about the system of presentation of one model. Who needs a model? We can find a perfect model - namely a cyrcle - in many pre Greek civilizations and after them. I also meant that astronomers were not able to discover p on their own till Newton. Thabit, Brahe and Copernicus (and perhaps someone else) they all have certain models, but only Newton was able to calculate the speed of Earth's p quite accurately...
  • One remark on other discoveries of precession: people should have noticed that the appearence of stars during the seasons changed over the course of centuries long before Hipparchus. The observation only has meaning within some theory how the universe is put together - precession means some invisible point is moving with respect to some invisible grid. Only the Greek had a geometric model of the universe (with rotating spheres) where the concept of precession makes sense.
And something about a will to work here in Wikipedia. For example, some years ago I've spent a lot of time to reconstruct the Omar Khayyam's observatory in Isfahan. If I know that it would be accepted here I would post it here - and I guess I won't. (You can also see it here if you please - I can even translate it for you, if there is something what is not understandable... This is fact my only official publication at Kvarkadabra - Slovene internet journal for interpretation of science). And I'll never go to Iran - that's for sure - at least in my life no. I've already sent you one of my attempts of doing one serious portrait of H, but you have just pointed me out that it does not have any value at all (phffikh... - sound as a bird's flying). Okay, fine. I accept that. But I must be tenacious. Hawking's mother said that nothing is strange if her son is thinking about the beginning of the Universe and where all that lost informations sucked in BHs went... I also have written in my native at my home page one translation and adaptation of John Major Jenkins' work about Mayan horizon astronomy. (See here.) I like his works - he's my age. We both wear beards, I guess, ha, ha. He jumps in Boulder, Colorado, and I at Celje, Slovenia. A huge differenece -. Well ... I also will never talk to Linda Schele. BUT - perhaps I am lucky enough to talk with Tom Peters.
  • You repeat the remark by Hoyle, which I never understood: was that a remark that he told you in personal meeting? What exactly was he referring to: your page (has it been around that long?), or our knowledge of Hipparchus and his work, or ...?
No, no - of course I never had met Sir Hoyle. (Surely I would be glad if I had that opportunity and possibility). I just meant that, as he was (sort of speaking) from the high English society (as he was knighted for his work in science), he just surely travelled also around some exotic places as Bosnia and Herzegovina is... There is an appendix to his famous book on the history of Astronomy, which deal with H and Ptolemy's works. His calculations are pretty hard for begginers and even for experts I guess, because even they need some solid observational data - (which are hard to attain even for you nowadays... (and to me of course)). I would like finally to excuse here for now because I can't write some more words - videlicet the motherboard of my home's PC went to hell's lands, and I have to wait to get a proper new one for my AMD's processor in the prime of its life... This much for now. BR --XJamRastafire 16:30, 22 Aug 2003 (UTC)

-- Tom Peters 12:27, 21 Aug 2003 (UTC)

The Farnese Atlas

I have added the following text to this article: "In 2005, it was reported [1] that information from Hipparchus' long lost star catalog may have been preserved in stone as part of the sculpture The Farnese Atlas." I also created the article at The Farnese Atlas. Johntex 18:43, 18 Jan 2005 (UTC)

On Jan 12 I also added information on this: http://en.wikipedia.org/w/index.php?title=Hipparchus&diff=9390382&oldid=9309072. It is symptomatic of the issues with this article that this wasn't more obvious. The article really needs work. A thought that may have already been suggested: maybe we could have a summary page, with a link to the content of the current article for those who want more background and details. Hipparchus background and details anyone? -- Mmm 02:10, Jan 19, 2005 (UTC)
Oops. Sorry about that, Mmm. I guess I did not read the article carefully enough. I like how you have incorporated the information. I do agree the article could use some clean-up. As far as I know, it is not customary to have a "summary" page, the summary is supposed to be the introductory paragraph. However, I have seen temporary pages created to allow for more easy editing when big changes are needed. I am not able to committ to helping on this one right now. I have a lot going at the moment, and I am no expert on this topic. However, I will try to stop by and see if there is a way I can lend a hand if I get the time. Best, Johntex 03:20, 19 Jan 2005 (UTC)

Reorg

What I had in mind is not really a summary, but more of a concise, readable overview without delving into so much background information and detail. There is a wealth of good stuff in the current article, but it seems a bit bulky and it could really use some wordsmithing, editing, and organizing (as has been pointed out by others). Further, I see that placeholders have been put in for even more detail and content. My thought was that it might be easier to move the current article to a new page, replace the current page with something more concise, and put many links to the original article for those that want to delve deeper. Maybe the sections could be something like this:

  • Brief biography, overview of life & contributions
  • Historical context, influences on him
  • Observations
  • Writings
  • Legacy, his influences on others

I'm sure others can come up with a better outine, but you get the basic idea. I think a few paragraphs on each section would probably give the average encyclopedia user the sort of information they are looking for. As examples to compare, the articles for Plato and Socrates seem about the right length. Like you, I don't feel I have the time or background to really take this on at this point, but I don't mind making the suggestion for someone else! :-) -- Mmm 07:29, Jan 19, 2005 (UTC)

I've largely completed a separate article that supercedes the Distance/Parallax subsection of this article. I've placed a link to the new article in that section, and I've attempted to incorporate as much of the information on this page into it as I possibly could. Barring any objections, I'm going to reduce the nine paragraphs in that section on this page to one, since the information is all redundant now. I suggest this as a model of how the Hipparchus page might be fixed. It would be much more manageable if these subsections were forked off into their own articles. --Dantheox 08:41, 25 December 2005 (UTC)

Elaborations on precession

Someone has added quite some text about precession, and I have several issues with that.

First, it is not accurate. Ptolemy did not confirm Hipparchus' results: his value is significantly different, and he under-estimated the rate of precession; Hipparchus' value was closer to reality. Also the false theory of trepidation of the aequinoxes was invented to match accurate medieval observations to the older but false observations handed down from Ptolemy.

Second, I consider this not NPOV. Ptolemy's star catalogue is highly controversial, and he has even been accused of fraud. So the presentation that he was in line with H. and with later astronomers is misleading.

Third, I find these elaborations out of place: the article, which is already too long, should concentrate on Hipparchus. I can agree that the relation to and differences with Ptolemy would merit attention here: but leave out what happened in the rest of the world before and after his time. That really should be moved to an article about precession proper.

Finally, be very critical about even older cultures knowing about precession. Especially tales about the Egyptians are highly misleading. Anyway, Hipparchus would know nothing about them.

Tom Peters 12:50, 1 March 2006 (UTC)

IMO the useful information about precession should be salvaged and put into a slightly more general article on history of precession, or some such. Even though he is the standard discoverer, Hipparchus' role is not really enough to warrant a separate article, but one that compared him with Ptolemy, added trepidation, etc., could be worthwhile. Likewise, there should be an article about Babylonian influence on Greek astronomy in general, not limited just to Hipparchus. Oh yes, I just started an article on Greek astronomy which might be another place to dump some information. Maestlin 04:33, 14 March 2006 (UTC)
  • I have begun an article on the Discovery of precession by copy-and-pasting from Hipparchus. I decided it would take a lot of heavy editing and rewriting to make it more readable (to me, anyway) and less presentist. I have also set up the article so that it accomodates statements about older cultures knowing precession without affecting the Hipparchus content. Any feedback or contributions would be welcome. If anyone looks at it right now, the unmodified text is between a couple of screeen-wide lines. Once the new article has been hammered into shape, there will be something worthwhile to summarize for this one in place of the current text. Maestlin 02:25, 25 March 2006 (UTC)

Star Catalogue

Maestlin,

I like your re-write of the section on Hipparchos' star catalogue. About 3 years ago I had an edit war with XJamRastaFire, and I got bogged down before re-writing that section, which thusfar has been mostly X's rather confused text. Maybe stress the point that Ptolemy adapted and extended H's catalogue, so superseded it, which is why H's original work has not been preserved. It was on P's, not H's catalogue that later islamic astronomers built. Note that in his commentary on Aratos, H lists polar distances of stars, which are equivalent to declination: he appears to have used mixed aequatorial and ecliptic coordinates; P later used ecliptic coordinates exclusively; I don't understand the remark about a "real" coordinate system. Also he is famous for having made a celestial globe. Do you have a reference for Pliny's mention of a nova? Tom Peters 16:49, 3 June 2006 (UTC)

Thanks. For basic factchecking of Pliny's mention of the nova (which was already in the text), I went to James Evans' survey (it's on p. 247); the source is Natural History II.95. I have no idea, either, what is meant by the "real" system, so I was slightly conservative in editing. Ptolemy's star catalogue is a contentious subject. I won't write up anything on it until I have a chance to review the R. R. Newton debate, which might be a while. This article still needs a lot of work before it's useful as an encyclopedia article for a general audience. It seems like it was trying to include everything ever written about Hipparchus. Maestlin 20:42, 5 June 2006 (UTC)
Not much is known about H. anyway, but a few years ago I did read up on him, and because the Wikipedia article was very poor I started writing, and kept writing, and writing... He did in fact have a very fruitful career, and we know the titles of 13 books. I think it is valuable to not just mention his studies and results, but also describe his methods because it shows how people back then approached phenomena that everyone can still see and wonder about today. As for the controversy on Ptolemy's star catalogue: that is a very hairy subject in which a minority group has a very vocal position. Anyway it involves Ptolemy rather than Hipparchos so better not rake up the mirk too much here. Tom Peters 23:14, 8 June 2006 (UTC)

which contributions to astrology

The most recent edit drew this line to my attention: "Astrology developed in the Greco-Roman world during the Hellenistic period, borrowing many elements from Babylonian astronomy; some historians have suggested that Hipparchus played a key role in this."

I believe the recent edit was to word the paragraph in such a way to indicate there is no evidence that Hipparchus himself was an astrologer. That's fine. But I think it should be more specific about what unique astronomical elements Hipparchus contributed to the development of astrology. What about his astronomy was unique from Babylonian astronomy? One thing attributed to Hipparchus that was useful to astrology was the division of the zodiac into 12 signs of equal degrees (30 each). Any other contributions? Zeusnoos 14:10, 17 July 2006 (UTC)"

I made the last edit, and I would be totally happy if you could substantiate additional claims. I don't know whether he was the first to use 12 zoodiacal signs of 30 deg; I did read he was the first to use a circle of 360 deg. His unique contribution was that he was the first to derive quantitative parameters for the abstract geometrical models that the Greek had developed to qualitatively explain the motion of the Sun and Moon. So for the first time it was possible to compute an ephemeris based on a geometrical model, instead of using the phenomenological Babylonian period relations. Before him, no-one could reliably predict a solar eclipse. But apparently he never got to apply his method to the planets, so his influence on astrological computation must have been limited. Tom Peters 15:51, 17 July 2006 (UTC)

Solar and lunar theory

Does anyone checking this page know the rationalization for separate sections on "motion of the moon" and "orbit of the moon" (and ditto for sun)? "Orbit" is anachronistic in this context. I am unsure what the editor was trying to distinguish. Maestlin 00:37, 28 March 2006 (UTC)

I originally made that distinction: "motion" refers to period lengths and ratio's babylonian style; "orbit" refers to geometry, which is Greek and in which Hipparchus made his most innovative contributions. Tom Peters 15:40, 17 July 2006

So "orbit of the moon" is something like "lunar theory" then? Maestlin 17:52, 20 July 2006 (UTC)

Well, "lunar theory" if I'm not mistaken nowadays refers to the dynamical description of the motion of the Moon under influence of the gravitational (and other) forces of th Earth, Sun, and planets. The ancients had no such concepts. The Hellenistic scientists treated the motion from a geometric or even mechanical model; the Babylonians apparently didn't care about mechanics but only about events and positions, which could be predicted with simple period relations and arithemetic. Tom Peters 01:26, 22 July 2006 (UTC)

The word "theory" is used somewhat differently in the history of premodern astronomy. It's fairly common to write of the solar, lunar, and planetary theories of Ptolemy and Copernicus, for instance. I have in mind accomplished specialists like O. Neugebauer and N. Swerdlow, not astrophysicists attempting to understand predecessors in familiar terms. Let me ask in another way: By "Orbit of the Sun" you meant that Hipparchus explains the solar phenomena with an eccentric, with such-and-such eccentricity, apsidal line, and tropical year? Maestlin 18:42, 25 July 2006 (UTC)

Well, yes: Hipparchus distinguishes himself from the Babylonians who only worked with a numerical model of the observable phenomena; and from his Greek predecessors who would draw a qualitative geometric model but never fitted the numerical details to observations. Hipparchus seems to have been the first to create models - theories if you like - that were both qualitative and quantitative valid (i.e. that they described, explained, and predicted the observable phenomena). So "lunar theory" in the classical sense would not be an alternative title for my "orbit", but could refer to the merge of the two sections of motion and orbit, if you believe that they should be merged. I have them separated because they come from two separate traditions, can be treated separately, and I don't want to make very long sections. Tom Peters 07:34, 26 July 2006 (UTC)

I'm not 100% sure I follow your reasoning. I brought this matter up in the first place because I am looking for ways to improve Wikipedia's coverage of Hipparchus more useful to general readers; I doubt whether the current version serves their interests. I understand the desire to preserve information that has already been entered into Wikipedia, even though I personally find the sections on planetary motions to be opaque. Maybe the best solution is to set up a separate article on this subject, and write a summary for this oversize page. Maestlin 19:13, 26 July 2006 (UTC)

briefly: as you see, "motion" refers to period lengths. Babylonians used period relations to predict recurrence of events, and most of the values that Hipparchus and Ptolemy used seem to have come from there. "orbit" deals with the typically Greek geometrical models. Before Hipparchus, they would treat planetary motions qualitatively and explain it by excentrics or an epicycle: without however determining the excentricity or size of the orbits from observations, i.e. in a quantitative way.
Anyway, I agree that the article is long: but in what way is it not useful to general readers? My intent has been to collect here what is known about Hipparchus, which is not much, and explain the concepts and put it into context. Wikipedia is not limited by constraints of printing costs and book sizes, so I see no reason not to be comprehensive. The first few paragraphs treat Hipparchus briefly for the casual reader. Tom Peters 11:24, 28 July 2006 (UTC)

Why do I think the article is not useful to the general reader? The reason actually is that it does not say enough about Hipparchus. For instance, the section on the sun and moon IMO doesn't sufficiently explain his synthesis of Babylonian and Greek methods, his inability to create models for the five planets, his reported critique of Greek colleagues for creating inadequate models, or his influence on Ptolemy and possibly Indian astronomy. The article is strong on numbers and method, but still poor in context and in striking a happy medium. It's already pushing the upper limits of article size, and if any more information is added, it will definitely be too long. I'm not worried about saving bytes; I'm concerned about the psychological problems with reading and editing a very long article on a computer screen. Maestlin 18:55, 28 July 2006 (UTC)

Oh well: I guess this is because little is actually known about Hipparchus and his sources and influence (except on Ptolemy), and what we know is derived from references and congruences in (much) later sources. I collected various papers from the past 4 decades, mostly listed under the Literature, and what is in the article is what they tell. I left out the geometrical proofs that they reconstructed. In fact this article contains more info than those on similar lemmata e.g. Ptolemy. Considering the length: I think that what you started, i.e. splicing the sections to their own articles and covering them briefly in the main article, is a valid approach. BTW I think Hipparchus was not inable to create models for the planets, but that he just never got to it. Tom Peters 23:12, 30 July 2006 (UTC)

I've been looking over the history of this article and I think I understand better how it came to be. "Inable" and "never got to it" are probably the same thing in this case. We know he did some work on planetary theories thanks to Almagest IX.2, which combines factual reporting and speculation on Hipparchus' chains of reasoning. Some of the other articles could use more information on the maths, like Ptolemy; actually a fuller discussion of Hipparchus' solar and lunar work could take up some of the slack. Looks like I won't get to it for a while though. Maybe for a long while, since I'll be moving and won't have the ready access to an academic library I've been enjoying. This article has a lot of good points and I just can't do it justice right now. Maestlin 19:25, 1 August 2006 (UTC)

Chord table and Pi

According to the present article:

For his chord table Hipparchus must have used a better approximation for π than the one from Archimedes of between 3 + 1/7 and 3 + 10/71; perhaps he had the one later used by Ptolemy: 3;8:30 (sexagesimal) (Almagest VI.7); but it is not known if he computed an improved value himself.

The article chord seems to imply that what Hipparchus actually approximated (implicitly or explicitly) was the reciprocal, 1/π, as 0;19:6 sexagesimal. This could be compatible with the above: 1/(3;8:30) = 0;19:5.8889 ; true 1/π= 0;19:5.9156 . But 7/22 = 0;19:5.4545 and 71/223 = 0;19:6.188, so equally he could simply have picked the only whole number of seconds in that range. Jheald 01:35, 10 October 2007 (UTC)

First heliocentric system??

I'm pretty sure Aristarchus is believed to have been the first to propose heliocentrism, actually.. See wikipedia entry on Aristarchus or heliocentrism. Also confirmed by Science and Technology in World History by McClellan and Dorn (pg 82-83), second edition. —Preceding unsigned comment added by 142.104.112.22 (talk) 01:45, 19 October 2010 (UTC)

The article does not say that Hipparchus was the first to propose heliocentrism, but the first to calculate it, which is not the same thing. However, no source is given even for that statement. — Joe Kress (talk) 03:39, 19 October 2010 (UTC)
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