Hipparchus (about 190-125 BC), also translated as Hipparchus, Hipparcus, Ibaku, Ibaku, etcancient GreekAstronomer, mathematician.He compiled a list of 1022 stars“the magnitude”To distinguish the stars;ProposedPtolemy Theorem 。
In the Chinese world, the translation of Hippocas is extremely inconsistent. In addition to Hippocas, there are also Hippocas, Hibakus, Ibaku, Ibaku, etc. This is because of hisChinese translationMost of them are translated from English. Hipparchus is hisAncient GreekPseudonymousEnglish translationAfter two translations, there is a big difference between the Chinese translation name and the accurate pronunciation of its mother tongue.Among them, the most popular ones are Hipparchus and Ibaku. When referring to this astronomer, he is generally called Hipparchus, while when referring to the astronomer named after himAstronomical satelliteIbaku satelliteAnd relatedAstronomical terminology(e.gHipparcos catalogue ）It is generally called Hipparcos because Hipparcos is used instead of Hipparchus in astronomical terminology.
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Hipachas
Xipachias calculated that the length of a year is 365 and 1/4 days, then subtract 1/300 days;findBai DaoArches andYellow white intersectionThe distance of the moon is 30 and 1/6 times the diameter of the earth;The movement table of the sun and the moon over the centuries was compiled and used to calculate the solar eclipse andlunar eclipse。He discovered new stars in 134 BC, which prompted him to compile a list of 850 star positions and brightnessCatalogue。InventedLongitude and latitudeexpressgeographical positionAnd projection drawing.
In order to study astronomy, Hipparchus foundedTrigonometryandSpherical trigonometry。Hipparchus left a lot of observation data.Later generations often use his observation results when determining various periods and parameters of planets.In 1718, Haley compared his observations with the records of Hipparchus and discovered the self motion of stars.His works have not been handed down, and all the known works about him are derived from Ptolemy's works.
According to legend, Hipparchus had very good eyesight, and was the first to discoverCancerOfM44Honeycomb clusters.Hipparchus used self-made observation tools and createdTrigonometryandSpherical trigonometryIt is measured that the time taken for the earth to circle the sun is about 36525-1/300 days, only six minutes from the correct value;He also calculated a lunar cycle of 29.53058 days, which is very close to the 29.53059 days calculated today.
In 130 BC, Hipparchus discoveredEarth orbitUneven, the summer solstice is far from the sun, and the winter solstice is near the sun.He madethe magnitude, queryAristotleThe theory that stars never grow or die, and produced the first western catalog:Hipparcos catalogue 。
Hipparchus was a great astronomer in Greece.Also, although he may have been educated in AlexandriaHe did not have.Working there, this unusual practice is also related toArchimedesbe similar.He isaegean seaOfLotEstablished himobservatoryAnd invented many instruments to observe the celestial phenomena with the naked eye. These instruments were used for 1700 years later, and Hipparchus inheritedAlistarkThe study of measuring the size and distance of the sun and moon.Not only did he use Alistark'slunar eclipseMethod, also measured the moonparallax。When you move your own position, you will find that the position of a near object changes significantly compared with that of a distant object, which is known as parallax.(Looking out from the train window, you can see that the nearby tree is moving relative to the distant tree.) The moving angle of the near object depends on both the size of its own position change and the distance of the near object. Knowing the moving distance, you can calculate the distance of the object.To do that,Right angled sideandhypotenuseConstitute variousright triangleThe proportions of the sides must be known.At that time, this theory was known to all. Some mathematicians tried to use these proportions, but Hippachas first made accurate tables of these proportions, so he is generally considered as the founder of trigonometry.
Under proper change conditions, by measuring the position of the moon relative to the stars, we can measure the parallax of the moon and calculate its distance. He found that the distance is 30 times the diameter of the earth, which is correct.If someone uses this value forEratostheniThe measured diameter of the earth would indicate that the moon is 250000 miles away from the earth.Unfortunately, no other celestial body is so close to the earth as the moon, so there is no such large parallax.Before the invention of the telescope, no other celestial body had parallax large enough to be measured.Therefore, the moon is the only celestial body that people know how far away from the earth in the 1900 years after Hipparchus.
In 134 BC, Hipparchus foundscorpioOne of the stars was not found in the previous observation records.This is something that puzzles him.Today, stars that appear indistinct to the naked eye do explode occasionally, suddenly brighten and become visible, but inancient GreekIt is impossible to imagine such things in the era. People believe that celestial bodies are eternal. Since previous observations were essentially unsystematic, Hipparchus cannot easily say whether this planet is the opposite.He decided to draw an accurate star map marked with the continuous positions of more than 1000 bright stars, so that future astronomers would not encounter similar difficulties.This is the first accurate star map, far better thanOdoxAnd Eratosthenes' early star maps.In order to draw this star map, Hipparchias used the latitude of each star (theAngular distance）Longitude (the angular distance from any point), mark its position.By analogy, the position of the earth's surface can be easily marked with the same method.We all noticed that 150 years ago,DesiacusLongitude and latitude have been used on the map.However, since the beginning of Xipachias, longitude and latitude have become well organized coordinate grids on the map, which have been used until today.
Hipparchus is also the first one based on the brightness of starsJiangxingThe brightest 20 stars in the sky are“First-class star”, thenLuminanceIt decreases to the second, third, fourth and fifth order, and the sixth order stars can just be observed with the naked eye. This arrangement system has been maintained to this day (although it has been improved and developed during this period).
The most ambitious achievement of Hipparchus is to research a new picture of the universeCelestial picture。Odox's sky map, earlierCalipsAnd Aristotle's theory makes the sky full of a large number of celestial spheres, and this method is the most practical.So Xipachias started to solve these problems with a new perspective. These problems were put forward by Apollonius half a century ago, but could not be developed at that time.Hipparchus reduced the number of celestial spheres within the outermost starry sky to seven, and each planet has a celestial sphere.But a single planet is actually not the center of the celestial sphere.When the small celestial sphere rotates, the planet moves in a circle. When the center of the small celestial sphere rotates as part of the large celestial sphere, the planet also moves in a circle at the same time. The large celestial sphere is the "mean wheel", and the small celestial sphere is the "current wheel".
By adjusting the speed of the two celestial spheres, the current round is stacked on the increasedEven wheelIt can be completely consistent with the actual operation of the planet.Hipparchus also used eccentric motion to solve the problem;That is, he believes that the planets do not revolve around the center of the earth, but revolve around a hypothetical point in space close to the center of the earth, which itself revolves around the center of the earth.The cosmological map of Hipparchias is very complex, but it retainsPlatoAnd Aristotle's principle, to the effect that the earth is the fixed center of the universe, and the movement of the planets is the synthesis of multiple circular movements.
In fact, Alistark's view that planets revolve around the sun seems much simpler, so it seems that it should prevail.But this is not the case.Morality, hard to imagine the whole earthFlying all over the sky(Unless you were taught that when you were a child, you would be credulous of anything).Moreover, the sky map of Hippachas is useful, but that of Alistark is not.The position change of the planetreligious ritesIt is very important and also important in astrology.What Hippachas has done is to create a mathematical system that can calculate the position of planets at any time in the future.
The current round, average roundEccentric circleHelp him calculate, just like drawing onGeometryOnguideHelp people prove theorems.Looking back today, I think that there is no reason to think that "auxiliary lines" are real, but astronomers insisted that these are real during the 1600 years.Of course, whether the auxiliary line is true or not, the method of calculating the position of the planet by Hipparchus still works.Finally, whenCopernicusWhen the mathematical calculation method of the Alistark celestial body theory is really developed, the life of the Hipparchus celestial body theory is ended.
Theorem expression: in the inscribed quadrilateral of a circle, the area of the rectangle enclosed by two diagonals is equal to a groupOpposite sideThe sum of the area of the enclosed rectangle and the area of another group of opposite sides.
From this theorem, we can deduce that sinecosineThe sum and difference formula of and a series ofTrigonometric identityPtolemy's theorem is essentially about the basic property of four point circularity
129 BC
Complete his star catalog (these stars are classified according to a system he invented, which isSurface brightnessFoundation).
He calculated that a year is 365 days and 6 hours (actually 365 days, 5 hours, 48 minutes and 46 seconds),MoonThe year is 29 days, 12 hours, 44 minutes and 25 seconds (actually 29 days, 12 hours and 18 minutes).evermorelunar eclipseThe prediction can be accurate to within an hour.
The legendary Ebagu has very good eyesight, which is the first discoveryCancerM44 Honeycomb Cluster.
Ebague used self-made observation tools and createdTrigonometryandSpherical trigonometry, it is measured that the time taken for the earth to circle the sun is about 365.25-1/300 days, which is only six minutes different from the correct value;He also calculated a lunar cycle of 29.53058 days, which is very close to the 29.53059 days calculated today.
