Talk:Ibn Yunus

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Background info on Ibn Yunus Family[edit]

Ibn Yunus surname was Al-Sadafi, a very well known yemeni arab tribe from Hadramaut in Yemen, that had immagrated during the Islamic expansion mostly to Egypt and Al-Andalus. The historian Ibn Khaldun says [1]: "بنو الصدف - بفتح الصاد وكسر الدال المهملتين حي من حضرموت وحضرموت يأتي نسبه عند ذكره في حرف الحاء المهملة حضر منهم جماعة فتح مصر مع عمرو بن العاص واختلطوا بها‏."

Translated: Banu al-sadaf - ...are a district of Hadramaut...some of them attended the opening of Egypt(Islamic conquest of egypt) with A'mr ibn al-A's, then they stayed there. Jidan 10:56, 5 December 2006 (UTC)[reply]

Arab?[edit]

Having a title like "Al-Misri", "al-Andalusi" or "al-Afriqi", does not really make you not Arab, specially when you have another title/family name (in Ibn Yunus's case it's al-Sadafi). Ibn Khallikan in his book wafayat al-Ayan wrote that Ibn Yunus Sr. is from al-Sadaf, the Arabian tribe. Also, al-Sam'ani wrote that on his book al-Ansab. please check this page to see the cited texts from these books. About his name, alot of Arabic books mention al-Sadafi in his name or his grandfather's (the historian) name. Some of these books are:

Wafayat al-Ayan for Ibn Khallikan. p. 463. from alwarraq.net
Osd al-Ghaba for Ibn al-Athir. p. 32. from alwarraq.net
Al-Ansab for Sama'ani. p. 847-848. from alwarraq.net
Al-Wafi be al-Wafayat for al-Safadi. p 2559. from alwarraq.net

So, he's an Arab. --Lanov 06:28, 9 December 2006 (UTC)[reply]

Hardly! Ibn Khallikan lived a good three centuries after Ibn Yunus, Sr. and his claim sounds a great deal like Arab folk legend along the lines of Arab#Origin rather than actual history. I've already heard something to that effect from Jidan, so please see my response to him on my talk page. If you want to add a brief note that a 13th century jurist claimed that Ibn Yunus belonged to that tribe because one of his names was al-Sadafi, then that's verifiable. But treating that as unmitigated evidence that Ibn Yunus was an Arab from Yemen when a range of other sources, including his own, point to his Egyptian origins is original research. It's also worth noting that it was common practice for mawali to connect their lineage with an Arabian tribe for the prestige that it conferred at that time. The result is that Muslim peoples across Africa to this very day claim to be descended from Arabian tribes or directly from Muhammad when all the evidence points to their African origins. The controversy regarding Ibn Khaldun's ancestry for example comes to mind. — [zɪʔɾɪdəʰ] · ☥ 07:23, 9 December 2006 (UTC)[reply]

Treating those 3 references we have on the article, that just wrote "Egyptian astronomer" when describing ibn Yunus, as an evidence that he's Egyptian is original research. Saying or trying to say that he's one of the mawali is also original research. Degrading ibn Khallikan and claiming that his work is not actual history is also original research. BTW, the authors of these so-called "references" we have on the article lived 10 centuries after Ibn Yunus Jr. Does this make them better than ibn Khallikan?

Please provide me with the names of the "range of other sources, including his own" that point to his Egyptian origins? Because if you do not, it will original research. --Lanov 19:21, 9 December 2006 (UTC)[reply]

"Evidence that he's Egyptian"?? Ridiculous! You mean the fact he was born in Egypt, his father was a foremost specialist in Egyptian history and a biographer of prominent Egyptians, who never left Egypt, is called al-Misri, which unquestionably has no meaning besides Egyptian, is treated as one in mainstream literature cited--and it needs "evidence" that he's Egyptian?

His being Egyptian is not a question. The only question here is if Ibn Yunus can certainly be connected to that Arabian tribe. And let's not forget that that tribe would have supposedly come to Egypt a full three hundred years prior to his birth, but somehow a reasonable person is supposed to believe that this anecdote automatically makes him an Arab! It is one thing to include in his biography that such story exists, which is verifiable, and another entirely to treat it as indisputable fact, which it isn't. — [zɪʔɾɪdəʰ] · ☥ 21:38, 9 December 2006 (UTC)[reply]

1)Al-Misri, is just a title that you can get if you lived in egypt(misr). Look for example at Ibn al-Haitham, he had also the title al-Misri [2], alhtough he came from Basra. Or look at Abu al-Faraj al-Isfahani, who was an arab that lived in Isfahan,Iran but got the title because he lived there for some time, etc..
2) Ibn Khallikan citations which mention him as stemming from an arabian tribe, is a primray source and significant. Yes, he lived 200 years later as you said, but he took those citations from earlier sources.
3) As I said earlier in the talk page of Zerida (before she deleted becasue she accused me of being uncivil [3]), being knowledgable in egyptain histroy doesn't make you neceseraly one. The founders of Egyptology and most influental people like for example Jean-François Champollion, weren't coptic/egyptian.
4)Finaly, Ibn Yunus case is similiar to Ptolemy. He was born there and lived there, but still he is not considered egyptian, but rather greek.

Lets just say he was both, Egyptian and Arab; i.e. he was an Egyptian Arab. Jidan 00:20, 10 December 2006 (UTC)[reply]

I am not inclined to go around in circles repeating myself. I simply included the information that I mentioned before in his bio. It's up to you if you want to include information from Ibn Khallikan, but you might want to look up the meaning of a primary source. — [zɪʔɾɪdəʰ] · ☥ 07:53, 10 December 2006 (UTC)[reply]

I already know what I wanted to know and the discussion page in some articles (including this one) is more informative and more NPOV than the article itself.Jidan 00:06, 15 December 2006 (UTC)[reply]

Pendulum[edit]

He also invented the pendulum. What is that suppose to mean? He could either investigated it or found an interesting usage of pendula, not invented it. This needs to be rewritten. --Tone 22:11, 3 June 2007 (UTC)[reply]

Both the citations given to support the pendulum claim actually say that this was a myth started in 1684 by English historian Edward Bernard. It doesn't really help to cite sources that contradict the statement. Unless someone can come up with some authoritative sources, I'm going to put in that this is a myth --Chetvorno^TALK 06:47, 20 February 2009 (UTC)[reply]

The following articles, amongst others, are just such authoritative sources for the fact that there is no evidence whatsoever for the claim that Ibn Yunūs used the pendulum (or, as David King puts it, "the nonsense of Ibn Yunūs' invention of the pendulum", p. 45):

King, David A. (1979). "Ibn Yunus and the Pendulum: A History of Errors". Archives Internationales d'Histoire des Sciences. 29 (104): 35–52.
Hall, Bert S. (1978-09). "The Scholastic Pendulum". Annals of Science. 35 (5): 441–462. doi:10.1080/00033797800200371. ISSN 0003-3790. {{cite journal}}: Check date values in: |date= (help)

All the best. –Syncategoremata (talk) 15:18, 12 April 2010 (UTC)[reply]

I don't see why Galileo should be credited with the discovery of the Pendulum or Ibn Yunus with the first study of its oscilations

[4]

In "History of the Sciences in Greco-Roman Antiquity", By Arnold Reymond The studies of Euclid and Archimedies regarding equilibrium are cited pp 192-202 in 3. "Archimedes and Statics" which essentially address a rod extended across a fulcrum with weights attached to the end of the rods so that they balance, (a balance scale such as is used to weigh the feather of Ma'at against the ab or heart of a petitioner to Anubis in temple illustrations from the pyramid age) and then the condition that one of the weights is a compound pendulum with a discussion of how its oscillations affect the equilibrium. "The Moment of Interia I is the sum of the masses m multiplied by the square of their distances r from the axis of suspension". "The time of oscillation T is then equal to T= 2PI sqrt I/M. Archimedes method using moments resulted in a false conclusion but still represents an ongoing discussion amongst the Greeks. "If the calculations in the chosen numerical example be made it will be found that I for the compound pendulum is equal to 2 x 4^2 + 2 x 8^2 = 160, while for the simple pendulum it is only equal to 4 x 6^2 = 144." Given his acknowledged math skills Ibn Yunus might be considered to have considered this and commented with something like the three moments equation presently used in statics.142.0.102.12 (talk) 21:27, 14 April 2015 (UTC)[reply]

Article[edit]

Where the article says under Pendulum

"Recent encyclopaedias[13] and popular accounts[14] continue to repeat the claim that the tenth century astronomer Ibn Yunus used a pendulum for time measurement, despite the fact that it has been known for nearly a hundred years that this is based on nothing more than an error made in 1684 by the Savilian Professor of Astronomy at Oxford and Arabist Edward Bernard.[15]"

Because our view of both sun and moon cuts 0.5 degree, of which there are 360 increments in the 180 degrees horizon to horizon, and the rotation of our planet on its axis cuts 1 degree every 4 minutes, our astronomical observations provide a clock (360deg/(24×60)min = 0.25 deg/min) with which we can make observations of the time to the nearest hour by noting their positions with the naked eye, and finer observations by setting a pendulum to a length of a meter whereupon it will make 90 swings while the sun or moon pass through 3 degrees in 12 minutes and 450 swings in an hour. At their zenith either sun or moon have cut 90 degrees or six hours; at 45 degrees they have cut 3 hours, at 15 degrees 1 hour. As a rule of thumb if you hold your hand up at arms length with your fingers spread it cuts 30 degrees and your five fingers allow a further division to 6 degrees or 24 minutes. Close your hand to a fist and it cuts 22.5 degrees. Results may vary somewhat but you can use that surveyer's technique to locate which decan the sun or moon are in and if you wish check your results by using a plumb bob to establish a meridian through which the sun and moon may enter and pass to get noon or midnight to an accuracy of 1 minute when they have passed half way through.

The Egyptians began using star clocks for time measurements in the pyramid age.[5] and either a plumb bob or the straight edge of a reflecting pool aligned with the meridian in the Rameside period (see discussion pp 72-75) If a plumb bob their instrument was the Mekhert (mhrt) and Bey used in surveying possibly with the addition of a grid of threads to locate both the decan star and its height above the horizon. pp 98-106 there is discussion of the "creation of a system of equations for hour lengths" because the sidereal day is 3 minutes 51 seconds shorter than the solar day. Page 127 begins the discussion of the use of the plumb bob or Mekhert (mhrt) in shadow clocks during the daytime from the beginning of the New Kingdom.142.0.102.12 (talk) 05:34, 15 April 2015 (UTC)[reply]

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pendulum or plumb bob[edit]

I will bet that those who mentioned a pendulum were not that off as the Oxford scholar would want us to believe. Read Crichton E.M. Miller's fascinating book "The Golden Thread of Time" (2000) and you will begin to connect the dots. Stjohn1970 (talk) 03:15, 27 December 2022 (UTC)[reply]