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Equation of Time - does it correct for speed of light?
Because of Earth's elliptical orbit, the planet varies its distance from the Sun.
(From http://science.msfc.nasa.gov/headlin...ast04jan_1.htm) "perihelion both hemispheres were 147.5 million km from the Sun." "152.6 million km in July, which astronomers call aphelion" A difference of 5.1 million km. the speed of light = 299 792 458 m / s (5100000000 m)/(299792458 m/s)=17.01 seconds How much variance would this introduce in the EoT? Would this difference add up to an appreciable amount? -- CB |
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Equation of Time - does it correct for speed of light?
"cgbusch" asked:
Subject: Equation of Time - does it correct for speed of light? Because of Earth's elliptical orbit, the planet varies its distance from the Sun. (From http://science.msfc.nasa.gov/headlin...ast04jan_1.htm) "perihelion both hemispheres were 147.5 million km from the Sun." "152.6 million km in July, which astronomers call aphelion" A difference of 5.1 million km. the speed of light = 299 792 458 m / s (5100000000 m)/(299792458 m/s)=17.01 seconds How much variance would this introduce in the EoT? Would this difference add up to an appreciable amount? You can answer those questions yourself, by answering these questions: How does the speed of light affect the time of noon? How would the time of noon be affected if light were so fast that it went from Sun to Earth in 1/100 of a second? How would the time of noon be affected if light were so slow that it went from Sun to Earth in 100 days? -- Jeff, in Minneapolis .. |
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Equation of Time - does it correct for speed of light?
"cgbusch" wrote in message om... Because of Earth's elliptical orbit, the planet varies its distance from the Sun. (From http://science.msfc.nasa.gov/headlin...ast04jan_1.htm) "perihelion both hemispheres were 147.5 million km from the Sun." "152.6 million km in July, which astronomers call aphelion" A difference of 5.1 million km. the speed of light = 299 792 458 m / s (5100000000 m)/(299792458 m/s)=17.01 seconds How much variance would this introduce in the EoT? Would this difference add up to an appreciable amount? I make it +/- 23 milliseconds. Paul Schlyter already answered this but maybe you missed it. I don't know if you are familiar with stellar aberration, my apologies if you already know this. If you point a telescope at a star at some time of the year and again six months later, you find you need to change the angle slightly. In the heliocentric frame, the Earth is moving so you have to tilt the telescope slightly to avoid the light hitting the sides as in this diagram http://physwww.mcmaster.ca/~kingb/2C...aberration.jpg from these notes http://physwww.mcmaster.ca/~kingb/2C...Lecture_3.html It should be clear that the angle only depends on the speed of the telescope relative to the star. For the same reason it affects the angle of the shadow cast by the gnomon by the same amount. If you think of it from a geocentric perspective, the light we see was emitted from the Sun roughly 500s earlier and the Sun will have moved in that time. The error in position obviously depends on the time taken and that depends on the distance, but the angle by which the apparent location of the Sun is displaced is independent of the distance since it depends on the ratio of the error to the distance. The speed of the Earth in orbit varies from 29.29km/s to 30.29km/s so by my calculations the aberration angle varies from 20.15 to 20.84 arcseconds. The mean is 20.50 but remember the EoT tells you the difference between true noon when the Sun actually appears due south and noon based on mean time. If the orbit of the Earth were circular, the constant 20.5 arcsec offset would be incorporated in mean time so there would be no contribution to the EoT. It is therefore only the variation we need to consider. That is just +/-0.34 arc seconds and the Earth rotates that much in 23 milliseconds. If you compare the variation of 0.34 with the angular diameter of the Sun of about 1900 arcsec, it means the error is 5000 times less than the width of the Sun's shadow from a fine wire gnomon. The rotation of the Earth subtracts 0.464km/s * cos(latitude) from the orbital motion but again that is constant for any given location so obviously doesn't affect the EoT. The mean aberration angle means that the Sun appears to be due south about 1.366 seconds before that alignment actually occurs, reduced to 1.353s at my latitude of 51N by the Earth's rotation. Compare that wit the 2 minutes plus it takes the Sun to cross the meridian. HTH George |
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Equation of Time - does it correct for speed of light?
"cgbusch" replied to Jeff Root:
How much variance would this introduce in the EoT? Would this difference add up to an appreciable amount? You can answer those questions yourself, by answering these questions: How does the speed of light affect the time of noon? That is my question! You asked how *much* it would affect the time of noon. I asked *how* it would affect the time of noon. My question must be answered before it is possible to even try to answer your question. How would the time of noon be affected if light were so fast that it went from Sun to Earth in 1/100 of a second? How would the time of noon be affected if light were so slow that it went from Sun to Earth in 100 days? But it is not constant. True, of course. I attempted to simplify my reply. The fact of the variation is essential to your question but completely irrelevant to my answer. I would have done better to make up a different set of hypothetical values, such as: How would the time of noon be affected if the speed of light were 1 billion km/s? How would the time of noon be affected if the speed of light were 10 km/s? It varies up to 17.01 seconds, so the Earth has more time to rotate. Effectively, the EoT takes variable solar days and makes them uniform 24 hour days. Let's say on 1 "end" of Earth's orbit the light got to Earth in 1/100 of a second and at the other "end", it took 8,640,000 seconds. Unless I just don't understand what you are saying, this doesn't make much sense. I wonder if you misunderstood my hypothetical scenarios? Given that the speed of light is constant (in vacuum), you are apparently describing an extremely elliptical orbit. I was setting up two separate scenarios: One with a very high value of c; the other with a very low value of c. In the 1/100s case, the Earth would get to rotate 4.16e-5 degrees, while at the larger distance, it would get to rotate 36000 degrees. But I know it is not that simple. As the Earth moves away from the Sun it takes longer for the light to reach it and as the Earth moves towards the Sun it can take up to 17 seconds less. Those statements are correct in both your scenario and mine, but they are *almost* irrelevent in both your scenario and mine. George pointed out that the finite speed of light causes the very tiny change in angle called the aberration of starlight. With a sufficiently low value of c, the aberration would become significant in the equation of time. However, the Sun is continually lit, so this all could be moot. That was my point. I failed to think of the aberration of starlight because its effect with the real value of c is so miniscule as to be totally irrelevant. Aberration of sunlight cannot be measured because the edge of the Sun is too fuzzy to measure its position with the required precision. Only extremely careful measurements of star positions with very good instruments over long time intervals revealed the aberration. (Although for an observer on Mars observing Earth (because of Earth's distinctive features) it would have an effect on the Martian spying on noon in Washington DC - although perhaps just the light lag from Earth to Mars only...) Yes, this is equivalent to how the speed of light was first measured, by timing the eclipses of Jupiter's moons. -- Jeff, in Minneapolis .. |
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Equation of Time - does it correct for speed of light?
"George Dishman" wrote in message ...
"cgbusch" wrote in message om... Because of Earth's elliptical orbit, the planet varies its distance from the Sun. (From http://science.msfc.nasa.gov/headlin...ast04jan_1.htm) "perihelion both hemispheres were 147.5 million km from the Sun." "152.6 million km in July, which astronomers call aphelion" A difference of 5.1 million km. the speed of light = 299 792 458 m / s (5100000000 m)/(299792458 m/s)=17.01 seconds How much variance would this introduce in the EoT? Would this difference add up to an appreciable amount? I make it +/- 23 milliseconds. Paul Schlyter already answered this but maybe you missed it. I don't know if you are familiar with stellar aberration, my apologies if you already know this. If you point a telescope at a star at some time of the year and again six months later, you find you need to change the angle slightly. Geocentric In the heliocentric frame, the Earth is moving so you have to tilt the telescope slightly to avoid the light hitting the sides as in this diagram Still geocentric. http://physwww.mcmaster.ca/~kingb/2C...aberration.jpg from these notes http://physwww.mcmaster.ca/~kingb/2C...Lecture_3.html Roemer was Danish,he does'nt even get the first sentence right,Roemer did'nt determine the speed of Light,Roemer determined the Equation of Light. http://dibinst.mit.edu/BURNDY/Online...mer/index.html It should be clear that the angle only depends on the speed of the telescope relative to the star. For the same reason it affects the angle of the shadow cast by the gnomon by the same amount. "Speed of telescope" means nothing unless the poster is a monkey,next sentence makes less sense. If you think of it from a geocentric perspective, the light we see was emitted from the Sun roughly 500s earlier and the Sun will have moved in that time. Geocentric perspective/relative space The error in position obviously depends on the time taken and that depends on the distance, There are no errors in relative motion. but the angle by which the apparent location of the Sun is displaced is independent of the distance since it depends on the ratio of the error to the distance. "Ratio of error" has no meaning in the English language or any other. The speed of the Earth in orbit varies from 29.29km/s to 30.29km/s so by my calculations the aberration angle varies from 20.15 to 20.84 arcseconds. The mean is 20.50 but remember the EoT tells you the difference between true noon when the Sun actually appears due south and noon based on mean time. The EoT is the mathematical computation which reduces the inequality of daily longitudinal alignments to a constant alignment based on a 24 hour day/clock rather than a natural day which generates inequal alignments.The old chestnut to "remember" is actually a pathetic attempt to ask you to forget that relativists,the whole damn lot of them did'nt know that Newton was expressing the difference between absolute time and relative time as the EoT. Removing absolute time was removing one half of the Equation of Time,mean time specifically. If the orbit of the Earth were circular, the constant 20.5 arcsec offset would be incorporated in mean time so there would be no contribution to the EoT. If the Earth's orbit were circular there would be no EoT,there would only be the slight variation the poster brings up. It is therefore only the variation we need to consider. That is just +/-0.34 arc seconds and the Earth rotates that much in 23 milliseconds. If you compare the variation of 0.34 with the angular diameter of the Sun of about 1900 arcsec, it means the error is 5000 times less than the width of the Sun's shadow from a fine wire gnomon. The rotation of the Earth subtracts 0.464km/s * cos(latitude) from the orbital motion but again that is constant for any given location so obviously doesn't affect the EoT. The mean aberration angle means that the Sun appears to be due south about 1.366 seconds before that alignment actually occurs, reduced to 1.353s at my latitude of 51N by the Earth's rotation. Funny,funny,funny,along any line of longitude from North to South pole it will be noon,noon means longitudinal alignment be you at 30 degrees,50 degrees,80 degrees along that longitudinal line. Compare that wit the 2 minutes plus it takes the Sun to cross the meridian. HTH George You insulted the guy even if he does'nt know it. |
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Equation of Time - does it correct for speed of light?
"George Dishman" wrote in message ...
"Oriel36" wrote in message om... "George Dishman" wrote in message ... "cgbusch" wrote in message om... How much variance would this introduce in the EoT? Would this difference add up to an appreciable amount? I make it +/- 23 milliseconds. snip: no content Gerald, you haven't attempted to show an error in my calculation, nor have you offered a derivation of your own. Since you won't be able to do that without first learning how to apply Kepler's Laws to the Earth, I suggest you instead reply to the outstanding thread with the somewhat misleading subject "sundial & Earth's tilt questions". You said I couldn't depict the EoT on the figures so I have done that. If you now understand what they are showing, I will put back Figure 2 and you can comment on the point of the thread. http://www.dishman.me.uk/George/SolarDay/index.htm In case you have trouble finding the article, here is the recent content: Dishman" wrote in message ... "Oriel36" wrote in message om... ... Noon is the alignment of a longitude meridian with the Sun and at any given location on the planet from pole to pole this alignment takes place. Fine, and if you look at figures 1 and 3, you will see that the blue line representing the Greenwich Meridian is pointing at the Sun. This is (natural) noon on these days. As the Earth axially rotates to face the Sun and repeats the alignment you find that the second drawing in your website does not reflect the inequality but sundials do. a) The second drawing does not depict noon in any way. This is _intentional_. b) The series of drawing is _not_ intended to depict the inequality of natural days. I have told you that several times yet you still make the same error. If anything illustrates incompetence it is your inability to take onboard what I have said repeatedly. Your diagrams and especially the third diagram leaves no room to put the Equation of Time correction ... Looking first at figure 1, on Nov. 3 2003, the EoT has a value of 16m 26s and the Sun is ahead of mean time. The figure shows the meridian aligned with the Sun so that is natural noon. If the Sun is ahead of mean time, it is not yet noon by GMT so we have to subtract the 16m 26s. That means a clock on the wall of the Greenwich Observatory would show 11:43:34 when the Sun was due south on the 3rd. Do you agree so far? Now looking at figure 3, note that the EoT correction is also 16m 26s on the 4th Nov 2003. The same calculation applies so the clock on the wall would show 11:43:34 when the Sun was due south on the 4th as well. That means that from figure 1 to figure 3 is a change of exactly 24 hours. If you follow that and agree I haven't made any mistakes in the calculations, I will next talk about figure 2. George George If you ever decide to put a figure 3 in your graphics,be sure to show the alignments without applying the Equation of Time and then you will know why Newton (and you) is correct and why Mach was an idiot followed by the spacetime guy. If you have'nt figured out that absolute time is one half of the Eot correction here it is. "Absolute time, in astronomy, is distinguished from relative, by the equation or correlation of the vulgar time. For the natural days are truly unequal, though they are commonly considered as equal and used for a measure of time; astronomers correct this inequality for their more accurate deducing of the celestial motions. It may be, that there is no such thing as an equable motion, whereby time may be accurately measured. All motions may be accelerated and retarded, but the true, or equable, progress of absolute time is liable to no change. The duration or perseverance of the existence of things remains the same, whether the motions are swift or slow, or none at all: and therefore, it ought to be distinguished from what are only sensible measures thereof; and out of which we collect it, by means of the astronomical equation.... Absolute, true, and mathematical time, of itself, and from its own nature flows equably without regard to anything external, and by another name is called duration: relative, apparent, and common time, is some sensible and external (whether accurate or unequable) measure of duration by the means of motion, which is commonly used instead of true time; such as an hour, a day, a month, a year." |
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Equation of Time - does it correct for speed of light?
In article ,
George Dishman wrote: "Jeff Root" wrote in message m... "cgbusch" replied to Jeff Root: It varies up to 17.01 seconds, so the Earth has more time to rotate. Effectively, the EoT takes variable solar days and makes them uniform 24 hour days. Let's say on 1 "end" of Earth's orbit the light got to Earth in 1/100 of a second and at the other "end", it took 8,640,000 seconds. Unless I just don't understand what you are saying, this doesn't make much sense. I wonder if you misunderstood my hypothetical scenarios? Given that the speed of light is constant (in vacuum), you are apparently describing an extremely elliptical orbit. It is just the difference between the time of flight at perihelion and aphelion, 490s compared to 508s but that is so small the orbit is close to circular. THe difference in light time doesn't matter to the apparent position! Why? Well, suppose the distance doubles -- then the light time delay doubles too, and the object is able to move twice as far during the light time delay. But since the distance has doubled, this corresponds to the same change in _apparent_ distance during the light time delay. Therefore the light time delay doesn't matter. What matters is the velocity of the moving object, relative to the observer: the faster the object moves, the greater the apparent change in position during the light time delay, and this apparent change in position will be v/c radians, where v is the speed of the object relative to the observer, and c is the speed of light. -- ---------------------------------------------------------------- Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN e-mail: pausch at stockholm dot bostream dot se WWW: http://www.stjarnhimlen.se/ http://home.tiscali.se/pausch/ |
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Equation of Time - does it correct for speed of light?
"Paul Schlyter" wrote in message ... In article , George Dishman wrote: "Jeff Root" wrote in message m... "cgbusch" replied to Jeff Root: It varies up to 17.01 seconds, so the Earth has more time to rotate. Effectively, the EoT takes variable solar days and makes them uniform 24 hour days. Let's say on 1 "end" of Earth's orbit the light got to Earth in 1/100 of a second and at the other "end", it took 8,640,000 seconds. Unless I just don't understand what you are saying, this doesn't make much sense. I wonder if you misunderstood my hypothetical scenarios? Given that the speed of light is constant (in vacuum), you are apparently describing an extremely elliptical orbit. It is just the difference between the time of flight at perihelion and aphelion, 490s compared to 508s but that is so small the orbit is close to circular. THe difference in light time doesn't matter to the apparent position! I know, I said so in and The above comment was purely about the eccentricity of the Earth's orbit. Why? Well, suppose the distance doubles -- then the light time delay doubles too, and the object is able to move twice as far during the light time delay. But since the distance has doubled, this corresponds to the same change in _apparent_ distance during the light time delay. Therefore the light time delay doesn't matter. What matters is the velocity of the moving object, relative to the observer: the faster the object moves, the greater the apparent change in position during the light time delay, and this apparent change in position will be v/c radians, where v is the speed of the object relative to the observer, and c is the speed of light. It is easiest to see in heliocentric inertial coordinates. What matters is the direction from which the light arrives. The light that hits the sundial at noon was emitted a little over 8 minutes earlier but since the Sun is unmoving it still comes from the same direction regardless of when it was emitted. I think cgbusch is visualising the situation in geocentric co-rotating coordinates and the explanation is less obvious then. I'm sure you will know it Paul but it might be instructive for some other posters to consider it. ;-) best regards George |
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Equation of Time - does it correct for speed of light?
"Oriel36" wrote in message om... "George Dishman" wrote in message ... "Oriel36" wrote in message om... "George Dishman" wrote in message ... "Oriel36" wrote in message om... "George Dishman" wrote in message ... You said I couldn't depict the EoT on the figures so I have done that. If you now understand what they are showing, I will put back Figure 2 and you can comment on the point of the thread. http://www.dishman.me.uk/George/SolarDay/index.htm In case you have trouble finding the article, here is the recent content: Dishman" wrote in message ... "Oriel36" wrote in message om... ... Noon is the alignment of a longitude meridian with the Sun and at any given location on the planet from pole to pole this alignment takes place. Fine, and if you look at figures 1 and 3, you will see that the blue line representing the Greenwich Meridian is pointing at the Sun. This is (natural) noon on these days. As the Earth axially rotates to face the Sun and repeats the alignment you find that the second drawing in your website does not reflect the inequality but sundials do. a) The second drawing does not depict noon in any way. This is _intentional_. b) The series of drawing is _not_ intended to depict the inequality of natural days. I have told you that several times yet you still make the same error. If anything illustrates incompetence it is your inability to take onboard what I have said repeatedly. Your diagrams and especially the third diagram leaves no room to put the Equation of Time correction ... Looking first at figure 1, on Nov. 3 2003, the EoT has a value of 16m 26s and the Sun is ahead of mean time. The figure shows the meridian aligned with the Sun so that is natural noon. If the Sun is ahead of mean time, it is not yet noon by GMT so we have to subtract the 16m 26s. That means a clock on the wall of the Greenwich Observatory would show 11:43:34 when the Sun was due south on the 3rd. Do you agree so far? Now looking at figure 3, note that the EoT correction is also 16m 26s on the 4th Nov 2003. The same calculation applies so the clock on the wall would show 11:43:34 when the Sun was due south on the 4th as well. That means that from figure 1 to figure 3 is a change of exactly 24 hours. If you follow that and agree I haven't made any mistakes in the calculations, I will next talk about figure 2. George George If you ever decide to put a figure 3 in your graphics, Gerald, if you ever decide to read the page, you will find figure 3 is already there (it is figure 2 that is omitted as stated above). be sure to show the alignments without applying the Equation of Time Gerald, if you ever decide to read the page, you will find that is what was already done (as stated above). I suggest you try looking at the page _before_ criticising it to avoid further embarrassment. Now try to understand, the two diagrams on the page should _not_ be contentious. The aim is to lay down something simple we can agree before adding in the bit that will probably cause a disagreement. Please look again and see if I have addressed your concerns, then we can actually start to have a conversation. Remember these are _not_ intended to be an explanation of the EoT, the purpose is quite different as you will see when we can move on. All you have to do is show the Earth's alignment with the Sun(Noon) in terms of absolute time as distinct from showing it with the EoT applied and then you overturn a century's worth of ignorance.I do not particularily like the way Newton phrased the EoT but it is easy to understand where he is coming from. The matter can be expressed,in fact it begs expression in basic English but your diagrams will suffice when you include the Earth's alignment with the Sun in terms of a 24 hour clock,call it mean time,absolute time,clock time or whatever,the definition given by Newton will make sense and more importantly it cannot be tampered with. Gerald, I still get the impression you haven't looked at the figures since I updated them. You are still asking me to do something that is already done. http://www.dishman.me.uk/George/SolarDay/index.htm Figure 3 shows an alignment _exactly_ 24 hours after that in figure 1. Both alignments are _precisely_ the natural noon for that day. To achieve that, I had to use one of four particular days in the year but we can use the fact that the rotation of the Earth is constant to apply any conclusion to other days via the EoT since it deals with the variation of the natural day. So have you any complaints about those figures or can you agree that: a) Figure 1 shows the noon alignment on the 3rd Nov. b) Figure 3 shows the noon alignment on the 4th Nov. c) The Sun appears due south at 11:43:34 on both days. d) The figures are separated by exactly 24 hours. If you disagree, please say specifically what you think the error is. If not, please say you agree and we can move on. George |
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Equation of Time - does it correct for speed of light?
"George Dishman" wrote in message ...
"Oriel36" wrote in message om... "George Dishman" wrote in message ... "Oriel36" wrote in message om... "George Dishman" wrote in message ... "Oriel36" wrote in message om... "George Dishman" wrote in message ... You said I couldn't depict the EoT on the figures so I have done that. If you now understand what they are showing, I will put back Figure 2 and you can comment on the point of the thread. http://www.dishman.me.uk/George/SolarDay/index.htm In case you have trouble finding the article, here is the recent content: Dishman" wrote in message ... "Oriel36" wrote in message om... ... Noon is the alignment of a longitude meridian with the Sun and at any given location on the planet from pole to pole this alignment takes place. Fine, and if you look at figures 1 and 3, you will see that the blue line representing the Greenwich Meridian is pointing at the Sun. This is (natural) noon on these days. As the Earth axially rotates to face the Sun and repeats the alignment you find that the second drawing in your website does not reflect the inequality but sundials do. a) The second drawing does not depict noon in any way. This is _intentional_. b) The series of drawing is _not_ intended to depict the inequality of natural days. I have told you that several times yet you still make the same error. If anything illustrates incompetence it is your inability to take onboard what I have said repeatedly. Your diagrams and especially the third diagram leaves no room to put the Equation of Time correction ... Looking first at figure 1, on Nov. 3 2003, the EoT has a value of 16m 26s and the Sun is ahead of mean time. The figure shows the meridian aligned with the Sun so that is natural noon. If the Sun is ahead of mean time, it is not yet noon by GMT so we have to subtract the 16m 26s. That means a clock on the wall of the Greenwich Observatory would show 11:43:34 when the Sun was due south on the 3rd. Do you agree so far? Now looking at figure 3, note that the EoT correction is also 16m 26s on the 4th Nov 2003. The same calculation applies so the clock on the wall would show 11:43:34 when the Sun was due south on the 4th as well. That means that from figure 1 to figure 3 is a change of exactly 24 hours. If you follow that and agree I haven't made any mistakes in the calculations, I will next talk about figure 2. George George If you ever decide to put a figure 3 in your graphics, Gerald, if you ever decide to read the page, you will find figure 3 is already there (it is figure 2 that is omitted as stated above). be sure to show the alignments without applying the Equation of Time Gerald, if you ever decide to read the page, you will find that is what was already done (as stated above). I suggest you try looking at the page _before_ criticising it to avoid further embarrassment. Now try to understand, the two diagrams on the page should _not_ be contentious. The aim is to lay down something simple we can agree before adding in the bit that will probably cause a disagreement. Please look again and see if I have addressed your concerns, then we can actually start to have a conversation. Remember these are _not_ intended to be an explanation of the EoT, the purpose is quite different as you will see when we can move on. All you have to do is show the Earth's alignment with the Sun(Noon) in terms of absolute time as distinct from showing it with the EoT applied and then you overturn a century's worth of ignorance.I do not particularily like the way Newton phrased the EoT but it is easy to understand where he is coming from. The matter can be expressed,in fact it begs expression in basic English but your diagrams will suffice when you include the Earth's alignment with the Sun in terms of a 24 hour clock,call it mean time,absolute time,clock time or whatever,the definition given by Newton will make sense and more importantly it cannot be tampered with. Gerald, I still get the impression you haven't looked at the figures since I updated them. You are still asking me to do something that is already done. http://www.dishman.me.uk/George/SolarDay/index.htm Figure 3 shows an alignment _exactly_ 24 hours after that in figure 1. Both alignments are _precisely_ the natural noon for that day. To achieve that, I had to use one of four particular days in the year but we can use the fact that the rotation of the Earth is constant to apply any conclusion to other days via the EoT since it deals with the variation of the natural day. So have you any complaints about those figures or can you agree that: a) Figure 1 shows the noon alignment on the 3rd Nov. b) Figure 3 shows the noon alignment on the 4th Nov. c) The Sun appears due south at 11:43:34 on both days. d) The figures are separated by exactly 24 hours. If you disagree, please say specifically what you think the error is. If not, please say you agree and we can move on. George George I am flying out tommorrow and I will take the oppurtunity to thank you and especially in having to unearth a history that you will never see discussed.As much of this history is based on your great maritime nation of Britain I have to admire how they worked the sidereal method in with the EoT so that if noon or the alignment of the Earth with the Sun was lost for that day,they had a fallback. Now all that appears certain is that your early 20th century mentors had'nt the foggiest notion of the EoT and this is what Newton was presenting in terms of the difference between absolute time and relative time,they can be forgiven for they simply did'nt know but you do now,to defend these spacetime concepts which never made sense anyway you become a traitor so instead of applying your obvious intelligence and the genuine groundwork you've done towards rectifying things you find yourself in the same position as Einstein,knowing that his isolation of the Mercury does'nt work but unable to undo the damage. Until last week I did'nt know exactly whether the mariners corrected the clock to noon or applied the correction at noon because the procedure is lost to history but then you see these practical men adopting the best possible methods of the EoT and the sidereal methods and by this means you can develop a great love and admiration for human endeavor.You will of course snip what you need to but that is fine,you have to live with the destruction of part of your heritage both as a national and more importantly scientifically. "The log was kept in ship's time, that is, the local apparent time, adjusted at intervals to the change of longitude: and by old practice an adjustment was made at noon, when the officer taking the latitude sight called "Twelve o'clock, Sir," and the Captain said "Make it so," (though the actual observations for local time were necessarily made morning and afternoon). If it were necessary to establish the accurate time of an event we should have to enquire more particularly whether the time of the nautical day was on that ship carried on from the noon on which it began, or adjusted to the noon on which it ended, or perhaps altered during the night from one to the other, as is more or less the present practice in merchant ships, though H.M. Navy keeps Standard Time. In default of better information we may without serious error (in days of sail) take the recorded hour as in the apparent time of the meridian of longitude mentioned in the account, and for form's sake apply the equation of time to reduce to civil time of the meridian" There is not one single thread in any of the sci.forums that is more important than this one,that you choose to remain and turf it out is a credit to you,that you choose to direct the original poster towards relativity ruins what you could have done or still can do. |
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