User:ABTOP/draft5
New COMMENTS: I want to delete the reasoning for the changes I want to make in WIKIPEDIA "EQUINOX". Really only the material listed at the end of this document is required to devise new statements for the Wikipedia Article.
I have to state that the equivalent information on Russian Wikipedia is quite correct in the article called "Ravnodenstvia" ("literally "Equal Days" or the Equinox"). It states the effects of the refraction by the atmosphere - the latter is necessarily absent for the effects of the official equatorial Equinox! The current article in Wikipedia I have to describe reluctantly as a travesty, because both types of "Equinox" need to be separated.
The Russian Wikipedia article on "Equinox": (Cited): @misc{ wiki:xxx, "http://ru.wikipedia.org/w/index.php?title=%D0%A0%D0%B0%D0%B2%D0%BD%D0%BE%D0%B4%D0%B5%D0%BD%D1%81%D1%82%D0%B2%D0%B8%D0%B5&oldid=2639248",
note = "[Online; accessed 20-январь-2007]" (20 January, 2007)
}
== My Experience: ==
At 72 years of age, I have for many years since college days been very interested in the subject of Time and related longitude/latitude effects. Originally from London, I have been staying here continuously since June 2004.
Part of my education was in a Polytechnic specialising in Horology, the classes being divided into four competitive houses named after prominent experts such as John Harrison. He, of course, provided the World with the first chronometer to function accurately in rough seas, enabling longitude to be better determined. As the attached interview with the local newspaper “Viva Cadiz” mentions, longitude and latitude were heavily involved in my calculations of my own observations of earth satellite orbital periods – which I transmitted to the Royal Aircraft Establishment at Farnborough – and were acknowledged as being very accurate, although by means of very elementary facilities.
Also relevant for the current subject of the Solar Radiation Hazard in Spain, as you will see, is my Experimental High Postgraduate Degree on the subject of the intensities of spectral UV emissions of gases present in reentry experiments concerning earth satellites (Imperial College, University of London).
Relevant == Wikipedia Reference ==
Page name: Equinox Author: Wikipedia contributors Publisher: Wikipedia, The Free Encyclopedia. Date of last revision: 30 December 2006 23:34 UTC Date retrieved: 4 January 2007 10:45 UTC Permanent link: http://en.wikipedia.org/w/index.php?title=Equinox&oldid=97425906 Page Version ID: 97425906 OR @misc{ wiki:xxx,
author = "Wikipedia",
url = "http://en.wikipedia.org/w/index.php?title=Equinox&oldid=97425906",
note = "[Online; accessed 4-January-2007]"
== COMMENCE: == (Explanation not required in actual change of article)
(Article submitted to local newspaper predicting differing Equinox Dates for Cadiz):-
1.0 Problems with Interpretation of the Equinoxes
In comparison to the ideas which prevailed with the "Druids of Stonehenge, England" in the past, it does seem that modern astronomers live in a fantasy world. It would be a few such astronomers using observations of the Sun being visible exactly for 12 hours on the day of the Equinox, who would have to believe that there is no atmosphere around the Earth to produce the mirage phenomena that we often see at sunset (the Sun can be seen when it is actually below the horizon, because the atmosphere acts like a lens, and refracts that image just above the horizon for some time). To us, the Sun will appear to be longer than 12 hours above the horizon on the 23rd of September, so that we will experience the Equinox 1 or 2 days later - and that will show up over the Weather Maps in the newspapers for that time! (Equal clock positions for both sunrise and sunset will indicate the twelve hours exactly, or perhaps closely enough to be significant).
To be fair, astronomers no longer observe the actual length of the day at Equinox, they are only interested in the exact time that the Sun is located at zenith over the Equator, and that will be at a particular place, too! According to information from Madrid which appeared locally on June 22nd, 2006, that time will be at 06:03 am Spanish Time, or 04:03 Z (UTC, GMT) on the 23rd September. That puts the location under the Sun near Kasimbar, on the island of Celebes in the Pacific.
But, "Hold on!", the Earth-Sun clock is running slower than the atomic clocks used by the astronomers at that date, by about 7 minutes! Thus, on a local sun clock at Kasimbar, the time of the Equinox will be shown as about 11:53 am in the time of that locality and not noon, as required! So, to where should the astronomers actually take their boat in the sea, in order to observe the actual event? That is a puzzle for me that will take more than 7 minutes to investigate!
== Observations in CADIZ, Spain: ==
As I stated above, the times for sunrise/sunset for the Mediterranean latitudes will look the same on the clocks everywhere there about the 26th of September, when I should be able to attach proof from the newspapers here for that !
END of Newspaper Article
1.2 Print out of a proof (in Spanish), accompanied by newspaper copy of their own proof (Sunrise/sunset times on 26th September, 2006.
== La C A Z A el “S N A R K” ==
== Lewis Carroll ==
( Hunting in a rowing boat for the elusive mythical creature! )
Snark = equinoccio de 2,006 - encima del ecuador (over the Equator)
== Equinoccio oficial fue el 23 / IX / 2,006 ==
== El sabado el 23 de septiembre : ==
¡Precisamente en el dia DOCE HORAS del sol con la condicion de la Tierra sin atmosfera!
( ¡ El primero dia del otoño por los astronomos ! )
== El martes el 26 de septiembre : ==
¡ Precisamente en el dia DOCE HORAS del sol con las dos de Tierra y atmosfera !
¡De acuerdo con la tradicion: el primero dia del otoño! The First of Autumn!
.....My own explanation of the situation concerning differing Equinox dates
==PREPARATORY INFORMATION: to explain my forthcoming changes - which are only attached for information in outline explanatory form beneath this set of explanations ==
2.0 == Description for Students==
(EXCLUDED HERE)
== Relevant for change explanation: ==
2.0 (revised)
Enlightenment is achievable because we know now why the "twelve-hour" definition is no longer to be correct.
Wherever on Earth (even at the Equator!) you observe the sunrise and sunset times, you will see the Sun for some minutes longer (up to hours longer in the Polar Regions!) than would have been expected. That is because when the Sun is near the horizon (even just below the horizon) the atmosphere we have behaves like a mirage-forming lens, apparently putting the position of the Sun slightly higher above the horizon (this effect is also well-known for the constellations at the horizon. Sometimes that image also appears distorted, just like a mirage). So that, even on the official Equinox date, the Sun everywhere appears for more than twelve hours, but not measurably near the Poles.
There is another, very important, factor appearing at such times. At the Equator, around the time of the Equinox dates, the Sun is observed to set perpendicularly into the horizon and reappears in the morning by rising also apparently "vertically". Although as described above, the Sun appears visible for more than twelve hours, this "diving" procedure means that the Sun appears to move more actively near the horizon and the mirage image does not last very long on the Equator (if I make an estimate, it would be a day which is just more than six minutes longer than twelve hours at the Official Equinox date). Conversely, an observer in the Mediterranean Region sees the Sun "meeting the horizon" at a gentler angle than from the "perpendicular" (further north still, observers see the Sun "glide" in or out of the horizon, so the Sun appears above the horizon for a much longer time in such locations, the mirage being available for much longer there).
What does this achieve for the investigator of historic Equinox dates? It means that he can explain clearly why the ancient Equinox dates were increasingly distant with increased latitude of the observers from the dates now derived by the new definition.
== Referring to the Table of Equinox and Soltice Dates on the Wikipage "Equinox" ==
I calculate that the Times of Equinoxes for 2002 to 2014 in that Table show the following very useful CONSTANT is present over much of the historical period of interest:
The Mean Annual "Delta Equinoxes" here is:...186d 09h 41.3m for those current years.
I calculate that the External Reference in that Wikipage for Times of Equinoxes for 1992 to 2020 yields:
A mean value for "Delta" of ... 186d 09h 44.24m for the 29 quoted years!
Reference to the larger table of Equinox dates and times in the External References I perceive to yield an error of less than about one day in 3000 years, In fact for the earliest record in that Table, the error appears as about +12 hours, so that the day indicated by the CONSTANT above is still about 186 days 21 hours!!.
Details of the Wikipage Table (used to derive the above Delta Equinoxes)
YR.....MAR.....JUN......SEP......DEC
Excluded here (Already on Wikipage)
==THE REAL NITTY_GRITTY==
2.5 ==ERRORS IN Wikipedia Articles:==
==ONLY THIS SECTION is the reason for changes to the Wikipedia Article cited. ==
==There would be NO change to the format of the original article!==
The paragraphs are shown in the order in the relevant Wikipage section
Comments by William Plumtree(mostly designed to be in italics!) added to original Wikipage article texts
== SECTION FOLLOWS - IN WIKIPAGE (cited) ==
==Heliocentric View of the Seasons ==(Original Wikipedia section title)
(Original text on Wikipage!) The cause of the seasons is that the rotation axis of the Earth is not perpendicular to its orbital plane, but makes an angle of about 23.44°, the obliquity of the ecliptic, and that this axis keeps its orientation in inertial space. By consequence, for half a year (from around 20 March to 22 September) the northern hemisphere tips toward the Sun, with the maximum /Insert "at the Solstice"/ around 21 June, while for the other half year the southern hemisphere has this honour, with the maximum /Insert "at the Solstice"/ around 21 December. The two instances that the Sun is overhead on the equator are the equinoxes. O K
Also at that moment both the North Pole and South Pole of the Earth are just on the "Terminator", and therefore day and night are equally divided over the whole globe. 'NO! This is wholly misleading. There is NO Terminator anywhere near either Pole. The Sun circles completely around and above the horizon at BOTH POLES because of the refraction at the horizon caused by the presence of the atmosphere. Day and Night are NOT equally divided ANYWHERE on the Globe on the official Equatorially-defined Equinox date, not even on the Equator!
The table above gives the instances of equinoxes and solstices over several years. A few remarks can be made. O K The actual equinox is a single moment in time — it does not take the whole day. O K But the crossing of the Sun over the equator is slow enough that the equinox day will have 12 hours of daylight and 12 hours of nighttime, and within an accuracy of a few minutes, the day before and after too. NO! For the same reasons. For the official equatorially-defined Equinox, the statement is completely wrong, since on the days just before or after (according to whether in March or September), the Sun shows for about three minutes longer than the 12-hours! Most probably on the second day away the Sun shows for either EXACTLY 12 hours, or nearest to that condition at the time! On the official Equinox Date on the Equator the Sun shows for just more than six minutes (estimate).
It is 94 days from the June solstice to the September equinox, but only 89 days from the December solstice to the March equinox. The seasons are not of equal length because of the variable speed the Earth has in its orbit around the Sun. O K
[[CAN ADD HERE: Something which is effectively constant over centuries is the time elapsed in each of the two cases of the official equatorially-derived Equinox dates in the given year and that of the "12-hour Sun" duration Equinox dates in the given year. The first "official" instance can be derived from a table of dates and times for 29 years of examples as shown in the "External Reference" Table of Times 1992-2020 www.aa.usno.navy.mil/data/docs/EarthSeasons.html, and I calculate amounts to 186 days 9 hours and 44.24 minutes, with a very small error margin. The change over time is probably of the order of one day in 3000 years! At other periods in history or the future the "computed" factor change can be estimated from the extrapolated data in the literature for the relevant epoch, if required. (See analysis above).]]
The instances of the Equinoxes are not fixed but fall about six hours later every year, amounting to one full day in four years, but then they are reset by the occurrence of a leap year. The Gregorian calendar is designed to follow the seasons as accurately as possible. It is good, but not perfect. Also see: Gregorian calendar#calendar seasonal error. Smaller irregularities in the times are caused by perturbations of the Moon and the other planets. Currently the most common equinox and solstice dates are 20 March, 21 June, 22 September and 21 December, the four year average slowly shifting to earlier times in the years to come. This shift is a full day in about 70 years (largely to be compensated by the century leap year rules of the Gregorian calendar). But that also means that as many years ago the dates of 21 March, 22 June, 23 September and 22 December were much more common, as older books teach and older people still remember. Note that the times are given in UTC, the time at Greenwich (ignoring British Summer Time). People living farther to the east (Asia, Australia) whose local times are in advance, will see the seasons apparently start later, for example in Tonga (UTC+13) an equinox occurred on 24 September 1999; a date which will not happen again until 2103. On the other hand people living far to the west (America) have clocks running behind in time, and may experience an equinox occurring as early as 19 March. ADD Here (recommended) Nevertheless, the official, astronomically accepted, Equinox Times should be the ones quoted worldwide in UTC (Universal Coordinated Time - historically called Greenwich Mean Time).
2.6 ==ERRORS on a further page in Wikipedia==
An equinox in astronomy is the event when the Sun can be observed to be directly above the equator.
O K
The event occurs twice a year, around March 20 and September 23. O K More technically, the equinox happens when the Sun is at one of two opposite points on the celestial sphere where the celestial equator and ecliptic intersect.O K
In a wider sense, the equinoxes are the two days each year when the center of the Sun spends an equal amount of time above and below the horizon at every location on Earth. Utterly misleading!! This would only occur realistically with the atmosphere absent! The "12-hour Sun Equinoxes" are very latitude-dependent because of the refraction variation with angle of interaction of the Sun with the horizon and many days can elapse between the relevant days!!
The word equinox derives from the Latin words aequus (equal) and nox (night). O K
The two instances that the Sun is overhead on the equator are the equinoxes. O K Also at that moment both the north pole and south pole of the Earth are just on the terminator, and therefore day and night are equally divided over the whole globe. Absolutely incorrect!! There is NO terminator at the Poles at Equinox!! (Only for NO atmosphere!) The Sun circles around the horizon above the horizon at BOTH Poles!
The table above gives the instances of equinoxes and solstices over several years. A few remarks can be made. The actual equatorially-derived equinox is a single moment in time —it does not take the whole day.OK But the crossing of the Sun over the equator is slow enough that the equinox day will have 12 hours of daylight and 12 hours of nighttime, and within an accuracy of a few minutes, the day before and after too. Very misleading! The "few minutes" are a descriptive device which succeeds in obscuring the true events on the Equator. The day before the March equatorially-derived Equinox has about 3 minutes extra sun over the 12 hours and the day after the September one also has about 3 minutes extra. TWO days different show about ZERO minutes extra!! On the actual Equinox day the Sun appears for more than 6 minutes extra!! However, it is true that the occurrence of the official Equinox at night times can displace the pattern of hours and dates to a degree. (see also similar criticism on page above)
22.7 == Geocentric view of the seasons ==
The explanation given in the previous section would be useful for an observer in outer space. Seen from Earth, the explanation remains the same but the orientation changes. Now the Sun revolves in one year around the Earth, moving along a circle in the sky named the ecliptic which is a reflection of the orbit of the Earth around the Sun. The daily motion of the Sun, (day and night), however, takes place parallel to the equator. The equinoxes are now the points where the equator intersects the ecliptic and the solstices the points on the ecliptic farthest away from the equator. Also note, in the drawing, when the Sun appears to be at the vernal equinox as seen from Earth, that seen from the Sun the Earth is 180° away from it, and thus at the autumnal equinox of its orbit. The perihelion of the Earth's orbit, currently located at 101° longitude, therefore occurs at the beginning of January. O K
As mentioned above, on*** equinox day the Sun passes through the zenith for observers on the equator and is on*** the horizon for those on the poles (but see also below). ***Prefer to see "Above the horizon at both Poles because of refraction". The March equinox marks sunrise at the north pole and sunset at the south pole, while for the September equinox it is just the opposite. Sorry, But you cannot say that since "The Sun circles above the horizon!!. For all observers on Earth the altitude of the Sun above the southern horizon at local noon is equal to the complement of the latitude (90° - φ). Example: an observer on 60° northern latitude (φ = +60°) will see the Sun at 30° in the south. An observer on 20° southern latitude (φ = −20°) will see the Sun at 110° in the south. But by then one has overshot the zenith (90° altitude), so that this value corresponds to 70° above the northern horizon. Acceptable approximation. On the equinox day, the Sun rises in the morning, for every place on Earth (except at the poles), exactly in the east and sets exactly in the west in the evening. ADD HERE (recommended) , but only does so perpendicular to the horizon at the Equator. (At high latitudes this may be shifted due to atmospheric refraction.) In the half year centred around June it rises and sets more towards the north, which means longer days and shorter nights for the northern hemisphere and shorter days and longer nights for the southern hemisphere. In the half year centred around December the Sun rises and sets more towards the south, and the day and night durations are reversed. O K Also on the visible for 12-hours-Sun "equilux day", the Sun rises, for every place on Earth (except at the poles), at 6:00 in the morning and sets at 18:00 in the evening. But these times are not exact for several reasons. 'NEEDS that addition' because it cannot possibly happen on the equatorially-defined Equinox day anywhere - even on the Equator, result of refraction
Most places on Earth use a time zone which is not equal to the local time, differing sometimes up to an hour, and even two hours if summer time is included. (or truly Double Summertime as in France and Spain as has happened over most of 90 years, for example). In that case, the Sun can rise for example at 8:00 and set at 20:00. Unfortunately that is the case in that part of Europe!! - see my other drafts!!. It means that in Vigo, Gallicia, Spain, the Equinox (12-hour Sun) dawn in September is about 08:25 am on the Spanish "Double Summertime" (CEST) and at about 07.40 am for March (CET).
Even those people fortunate enough to have their time zone just equal to the local time, they still will not see sunrise and sunset at 6:00 and 18:00, respectively. This is due to the variable speed of the Earth in its orbit, and is described as the equation of time. It has different values for the March and the September equinox (+8 and −8 minutes respectively). Glad to see this, however, I must point out for longevity here that the "Equation of Time" is constantly on the move. Iain Nicolson´s book on "The Sun" shows a plot for this valid for 1982, but in 2006-7 it is now FOUR MONTHS out of phase with reality. The April intersection with the axis has just occurred on December 25 approx. Surprisingly, the change is still advancing very rapidly on the 8th January, 2007 at about +6 mins (I do not have access to an up-to-date plot). Sunrise and sunset are commonly defined for the upper limb of the solar disk, and not for its centre. The limb is already up for at least one minute before the centre appears, and likewise sets one minute before the last appearance of the limb sets too. O K Due to the atmospheric refraction the Sun, when near the horizon, appears a little more than its own diameter above the position than where it is in reality. This makes sunrise more than another ***two minutes earlier and sunset the equal amount later. The two effects add up to almost seven minutes, making the equinox day 12h 7m long and the night only 11h 53m. In addition to that, the night includes twilight. When dawn and dusk are added to the daytime instead, the day would be almost 13 hours.***"Three" seems to fit, although it is approximate. The above numbers are only true for the tropics. For moderate latitudes this discrepancy gets larger (London, for example: 12 minutes), and close to the poles it gets very large. Up to about 100 km from both poles the Sun is up for a full 24 hours on equinox day. Somewhat surprised that it is not larger for Greenwich!
Height of the horizon on both the sunrise and sunset sides changes the day's length. Going up into the mountains will lengthen the day, while standing in a valley with hilltops on the east and the west can shorten the day significantly. This is why settlements in east-west running valleys are more favourable (daylight-wise) than north-south running valleys. O K
2.8 == Further points at foot of the Wikipedia page: ==
Equinoxes are points in time, but equiluxes are days. By convention, equiluxes are the days where sunrise and sunset are closest to being exactly 12 hours apart. This way, you can refer to a single date as being the equilux, when, in reality, it spans sunset on one day to sunset the next, or sunrise on one to sunrise the next. As an example, for a city 45°N and 123°W (Portland, Oregon), the 2006 autumnal equilux was on September 25 when sunrise was at 7:01 am and sunset was at 7:02 pm. The 2006 autumnal equinox was on September 22 at 9:03 pm (all times in Pacific Daylight Time). For the Northern Hemisphere, the autumnal equilux lags behind the equinox, and the reverse is true in the spring. As you might suspect, the whole situation is reversed for the Southern Hemisphere. O K Have no real problem, apparently. It may be just a little too simple to reverse all ideas for the South! It is helpful here to use the "incorrect" March and September Equinox nomenclature, because I find it is quite difficult to establish by mental reasoning what actually happens around the Equinox near to the Equator as a result of assessing the behaviour in each Hemisphere.
My inferences:
The behaviour of the "terminator" at times other than that of the Equinoxes is a source of confusion, because the terminator exhibits asymmetrical behaviour about the Equator at such times (a source of retained memory of behaviour). The behaviour of the Equinox - Equilux pair exhibits symmetrical behaviour about the Equator. For the Northern Hemisphere, the September Equilux lags behind the Equinox. For the Southern Hemisphere, the September Equilux also lags behind the Equinox. (It is nevertheless true that, as would be stated in Wikipedia, the Equilux is on the nearest Summer side of the Equinox!).
Exercise for the investigator interested in detail!
Portland, Oregon: Equatorial Equinox 22 Sept latish (evening) (9 pm local time PDT) Equilux day 25 th Sept of 12 hours-1 min approx (Both manifestations at 07:01 PDT would indicate a midday point for the Equilux), reduction of the Equilux day length at September - meaning the Equilux date/time is "late", is an indication opposite to the facts, therefore the indicated Equilux date/time was in fact "early", so that the Equilux in truth was later than midday if hours and mins are implied (lets say 3 pm PDT for convenience). There is no reason in analysis to ignore the actual hours (approx). As an exercise, it would mean that the difference in time between the Equinox and the Equilux was about 2 days 18 hours approx. This provokes a query! The difference seems too small for 45 degrees North? I have found (approximately, it is true) that the difference appears to be about 3 days at 36 degrees North (Cadiz, Spain). Therefore, should the difference not be greater for Portland?
My Analysis for CADIZ, Spain, differed at the time!
DATA for CADIZ.(San Fernando OBS) Equinox at 23 rd Sept 04:03 UTC, Equilux at 26 th Sept apparently midday UTC. Actual 12 hours zero mins reported with fairly symmetrical differences on days before and after Equilux. Difference therefore 3 days 8hours!! Something is amiss! Dare I suggest that the Equilux in September at Portland was also on the 26th, because my instances in accordance not only with local newspaper reports plus a report also for Gibraltar nearby, but also with my own observations of sunset at the time?
W E G Plumtree, M.Phil.(Lond - Imp. Coll), B.Sc.(Spec Phys), Formerly in Uk M.Inst P