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galileo galilei - dates to confirm
Hello,
A question about historical truth. It is said that Galileo discovered the phases of Venus phases in 1610. OK. It is also said that he invented his scope only in 1610 Two dates to be confirmed, and if possible in the month close... If I simulate the sky at that time, of Firenze, arcetri, we discover that in Jan-April 1610 Venus was in the East, 10° over the horizon with 80%+ illuminated, thus very small, and at the end in the rays of sun. hard to imagine that he observed it at that time. It nevertheless could have did it. On the other hand, at the autumn 1609 venus shows a fine crescent, and was higher in the sky of the morning Idem from October 1610 but, this time in the eve. However it would have published his Siderius Nuncius in March 1610 (also to re-confirm). Impossible thus that he observed the beautiful crescent of venus before publishing his book. It was thus to have written his explanation and signed the "go for printing", say at least 1 month before, in February If one assumes that it was very smart, it obviously could have interpreted the phases right between the invention of his scope and February 1610. But that leaves him just a few weeks, and in counting on clear sky every days, to discover the phases and its explanations, under bad seeing, without speaking about his optics.... The book having been published in March, he would thus have observed Venus at the worst moment of its phase Or he had to develop his scope in 1609... But here also, the first drafts of Giovanni Battista della Porta were published in August 1609... (to confirm as well). But that of Galileo would not have been invented yet at that time. That would tend to confirm that Galileo would have discovered the Venus phases at a time it had a small diameter ( 15-12" if I remember well) under very difficult conditions (both hardware and astronomical). The discovery would all the more be deserving. But is this well at that time that all that was held ? Who could find me the exact dates (invention of Galileo's scope, 1st obs., obser. of Venus phases, publication of Messenger, etc) Thanks in avdance Thierry http://www.astrosurf.org/lombry |
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galileo galilei - dates to confirm
Thierry wrote in message ... Hello, A question about historical truth. It is said that Galileo discovered the phases of Venus phases in 1610. OK. It is also said that he invented his scope only in 1610 Two dates to be confirmed, and if possible in the month close... Looks like the dates may be in error Wikipedia "Based only on sketchy descriptions of the telescope, invented in the Netherlands in 1608, Galileo made one with about 8x magnification, and then made improved models up to about 20x. On August 25, 1609, he demonstrated his first telescope to Venetian lawmakers." http://en.wikipedia.org/wiki/Galileo#Astronomy If I simulate the sky at that time, of Firenze, arcetri, we discover that in Jan-April 1610 Venus was in the East, 10° over the horizon with 80%+ illuminated, thus very small, and at the end in the rays of sun. hard to imagine that he observed it at that time. It nevertheless could have did it. On the other hand, at the autumn 1609 venus shows a fine crescent, and was higher in the sky of the morning Good work, and could well suggest that he observed Venus in Autumn 1609 rather than early in 1610. |
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galileo galilei - dates to confirm
"OG" wrote in message ... Thierry wrote in message ... Hello, A question about historical truth. It is said that Galileo discovered the phases of Venus phases in 1610. OK. It is also said that he invented his scope only in 1610 Two dates to be confirmed, and if possible in the month close... Looks like the dates may be in error Wikipedia Not sure that wikipedia is a formal source of information It will be not the first time that i correct data because references or commentaries are not accurate, mix with rumor, etc. I am agree that there are a lot of good things on wikipedia, I work on it as well, but I don't consider it as an official source. better to go to the museum of science of firenze, don't you think... Thierry "Based only on sketchy descriptions of the telescope, invented in the Netherlands in 1608, Galileo made one with about 8x magnification, and then made improved models up to about 20x. On August 25, 1609, he demonstrated his first telescope to Venetian lawmakers." http://en.wikipedia.org/wiki/Galileo#Astronomy If I simulate the sky at that time, of Firenze, arcetri, we discover that in Jan-April 1610 Venus was in the East, 10° over the horizon with 80%+ illuminated, thus very small, and at the end in the rays of sun. hard to imagine that he observed it at that time. It nevertheless could have did it. On the other hand, at the autumn 1609 venus shows a fine crescent, and was higher in the sky of the morning Good work, and could well suggest that he observed Venus in Autumn 1609 rather than early in 1610. |
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galileo galilei - dates to confirm
"OG" wrote in message ... Thierry wrote in message ... Hello, A question about historical truth. It is said that Galileo discovered the phases of Venus phases in 1610. OK. It is also said that he invented his scope only in 1610 Two dates to be confirmed, and if possible in the month close... Looks like the dates may be in error Wikipedia "Based only on sketchy descriptions of the telescope, invented in the Netherlands in 1608, Galileo made one with about 8x magnification, and then made improved models up to about 20x. On August 25, 1609, he demonstrated his first telescope to Venetian lawmakers." Right. My mistake. I reread , my notes (I always wonder of the number of information i found on my own site and that I have forgotten, of almost). Hopefully there is a search engine.... Galileo seems have demonstrated his scope already on August 21. Its magnification was 3x. Remain to confirm the first observation of venus and with what scope Thierry |
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galileo galilei - dates to confirm
It is also said that he invented his scope only in 1610
Heard that Galileo didn't invent the telescope, but was the first to look at objects in the sky as a scientist. Others who had telescopes for looking for ships and such probably took a peak at the Moon but never did anything with those observations. Also heard that the scope Galileo had was a real POS, and he would have loved to have gotten his hands on one of our Christmas gift trash scopes from WalMart. Even though those are POS's, they'd better his POS... |
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galileo galilei - dates to confirm
On 2006-09-11, Thierry Thierry wrote:
A question about historical truth. It is said that Galileo discovered the phases of Venus phases in 1610. OK. It is also said that he invented his scope only in 1610 Two dates to be confirmed, and if possible in the month close... If I simulate the sky at that time, of Firenze, arcetri, we discover that in Jan-April 1610 Venus was in the East, 10° over the horizon with 80%+ illuminated, thus very small, and at the end in the rays of sun. hard to imagine that he observed it at that time. It nevertheless could have did it. On the other hand, at the autumn 1609 venus shows a fine crescent, and was higher in the sky of the morning Idem from October 1610 but, this time in the eve. However it would have published his Siderius Nuncius in March 1610 (also to re-confirm). Impossible thus that he observed the beautiful crescent of venus before publishing his book. It was thus to have written his explanation and signed the "go for printing", say at least 1 month before, in February If one assumes that it was very smart, it obviously could have interpreted the phases right between the invention of his scope and February 1610. But that leaves him just a few weeks, and in counting on clear sky every days, to discover the phases and its explanations, under bad seeing, without speaking about his optics.... The book having been published in March, he would thus have observed Venus at the worst moment of its phase Or he had to develop his scope in 1609... But here also, the first drafts of Giovanni Battista della Porta were published in August 1609... (to confirm as well). But that of Galileo would not have been invented yet at that time. That would tend to confirm that Galileo would have discovered the Venus phases at a time it had a small diameter ( 15-12" if I remember well) under very difficult conditions (both hardware and astronomical). The discovery would all the more be deserving. But is this well at that time that all that was held ? Who could find me the exact dates (invention of Galileo's scope, 1st obs., obser. of Venus phases, publication of Messenger, etc) The phases of Venus are in "Dialog Concerning the Two Chief World Systems", which printed in 1632, and aren't in "Starry Messenger", which was printed in 1610. There are fairly recent English translations of both (Stillman & Van Helden). I've got the Reston bio of Galileo around here somewhere. As best as I remember, Galileo made a telescope sometime in 1609, not long after news of the invention reached him. Bud |
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galileo galilei - dates to confirm
Thierry wrote in :
"OG" wrote in message ... Thierry wrote in message ... Hello, A question about historical truth. It is said that Galileo discovered the phases of Venus phases in 1610. OK. It is also said that he invented his scope only in 1610 Two dates to be confirmed, and if possible in the month close... Looks like the dates may be in error Wikipedia Not sure that wikipedia is a formal source of information It will be not the first time that i correct data because references or commentaries are not accurate, mix with rumor, etc. I am agree that there are a lot of good things on wikipedia, I work on it as well, but I don't consider it as an official source. better to go to the museum of science of firenze, don't you think... Thierry True but good Wikipedia articles should give references to primary sources. Klazmon. "Based only on sketchy descriptions of the telescope, invented in the Netherlands in 1608, Galileo made one with about 8x magnification, and then made improved models up to about 20x. On August 25, 1609, he demonstrated his first telescope to Venetian lawmakers." http://en.wikipedia.org/wiki/Galileo#Astronomy If I simulate the sky at that time, of Firenze, arcetri, we discover that in Jan-April 1610 Venus was in the East, 10° over the horizon with 80%+ illuminated, thus very small, and at the end in the rays of sun. hard to imagine that he observed it at that time. It nevertheless could have did it. On the other hand, at the autumn 1609 venus shows a fine crescent, and was higher in the sky of the morning Good work, and could well suggest that he observed Venus in Autumn 1609 rather than early in 1610. |
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galileo galilei - dates to confirm
Thierry wrote:
snip. Remain to confirm the first observation of venus and with what scope Thierry You might find these pages of interest in Pope's and Mosher's project - WHAT GALILEO SAW http://www.pacifier.com/~tpope/Photo...rison_Page.htm VENUS THROUGH THE GALILEAN TELESCOPE http://www.pacifier.com/~tpope/Venus_Page.htm CCD IMAGES FROM A GALILEAN TELESCOPE http://www.pacifier.com/~tpope/index.htm - Canopus56 P.S. - Mosher and Pope note that the Venus drawings were first reproduced in a plate in Galieo's _Il Saggiatore_ (1623). Mosher and Pope also note that: "Galileo made many careful observations of the phases of Venus, yet we do not know of any manuscript pages containing the original drawings from which the plate was made." Galileo may have made his Venus observations at anytime between 1610 and 1623. |
#9
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galileo galilei - dates to confirm
Thierry wrote:
Who could find me the exact dates (invention of Galileo's scope, 1st obs., obser. of Venus phases, publication of Messenger, etc) He observed the phases of Venus about eight months *after* he published Sidereus Nuncius. Aug 1609 - completed and demonstrated a 9x instrument Nov 1609 - completed a 20x instrument and began observing the sky Mar 1610 - published Sidereus Nuncius Nov 1610 - began observing Venus Dec 1610 - announced observation of Venus phases Galileo demonstrated the 9x telescope to the Senate of Venice on 23 August 1609. (Galileo describes the demonstration in a 29 August 1609 letter which says, "...it has been 6 days since...") They observed ships at sea, not the sky. The letter at the beginning of Sidereus Nuncius dedicating the book to Cosimo II de Medici is dated 12 March 1610. Galileo announced his observation of the phases of Venus in a letter to Giuliano de Medici dated 11 December 1610. He hid the announcement in the form of an anagram, Haec immatura a me iam frustra leguntur o y which when unscrambled is Cynthiae figuras aemulatur mater amorum The mother of love emulates the figures of Cynthia Venus has phases like the Moon This is all from Albert Van Helden's English translation of Sidereus Nuncius. - Ernie http://home.comcast.net/~erniew |
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galileo galilei - dates to confirm
robert casey wrote:
Also heard that the scope Galileo had was a real POS, and he would have loved to have gotten his hands on one of our Christmas gift trash scopes from WalMart. Even though those are POS's, they'd better his POS... As I understand it, it wasn't the execution so much as the design. It had inherent aberrations, but the scopes he produced performed about as well as a modern example of the same design would. There was a recent article in Sky and Telescope or Night Sky about this. -- Brian Tung The Astronomy Corner at http://astro.isi.edu/ Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/ The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/ My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.html |
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