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[Ragoo]

Did you know that astronomy is the oldest of the physical sciences?

In many early civilizations the regularity of celestial motions was recognized, and attempts were made to keep records and predict future events.
The first practical function of astronomy was to provide a basis for the calendar the units of month and year being determined by astronomical observations.
Later, astronomy served in navigation and timekeeping.
The Chinese had a working calendar as early as the 13th cent. B.C. About 350 B.C., Shih Shen prepared the earliest known star catalog, containing 800 entries. Ancient Chinese astronomy is best known today for its observations of comets and supernovas. The Babylonians, Assyrians, and Egyptians were also active in astronomy.
The earliest astronomers were priests, and no attempt was made to separate astronomy from astrology .
In fact, an early motivation for the detailed study of planetary positions was the preparation of horoscopes.

[Ragoo]

Ancient Greek astronomy

Ancient Greek astronomy

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The ancient Greeks were the first to start developing astronomy theories about the design of the Universe.

from wiki
Greek astronomy is the astronomy of those who wrote in the Greek language in classical antiquity; for example, Aristarchus of Samos Greek astronomer/mathematician and his heliocentric model of the solar system.
Greek astronomy is understood to include the ancient Greek, Hellenistic, Greco-Roman, and Late Antiquity eras.
It is not limited geographically to Greece or to ethnic Greeks, as the Greek language had become the language of scholarship throughout the Hellenistic world following the conquests of Alexander.
This phase of Greek astronomy is also known as Hellenistic astronomy, while the pre-Hellenistic phase is known as Classical Greek astronomy.
During the Hellenistic and Roman periods, much of the Greek and non-Greek astronomers working in the Greek tradition studied at the Musaeum and the Library of Alexandria in Ptolemaic Egypt.
The development of astronomy by the Greek and Hellenistic astronomers is considered by historians to be a major phase in the history of astronomy in Western culture.
It was influenced by Babylonian astronomy; in turn, it influenced Islamic, Indian, and Western European astronomy.

Greek astronomy is understood to include the ancient Greek, Hellenistic, Greco-Roman, and Late Antiquity eras.
It is not limited geographically to Greece or to ethnic Greeks, as the Greek language had become the language of scholarship throughout the Hellenistic world following the conquests of Alexander.

This phase of Greek astronomy is also known as Hellenistic astronomy, while the pre-Hellenistic phase is known as Classical Greek astronomy.
The development of astronomy by the Greek and Hellenistic astronomers is considered by historians to be a major phase in the history of astronomy in Western culture.
It was influenced by Babylonian astronomy; in turn, it influenced Islamic, Indian, and Western European astronomy.

Most ancient civilizations watched the heavens as patterns in the sky that allowed the to know when the seasons changed - among other things.
They built great stone monuments called astronomical observatories such as Stonehenge as celestials clocks to mark these events and the passage of time.
They believed their gods lived in the skies and named them and the constellations after them.
This is the reason astrology, astrology and mythology all follow the same patterns. In the end - the answers are in the sky as they come from above. In metaphysics we call this moving into higher frequency than what we experience in our third dimensional bodies. Our creators are from higher realms.
They have powers that are lost to us in the physical body. Many seek to activate those powers now.




Ancient Greek astronomy

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Gradually moving from a system of gods and divine powers ordering the world to a system of elements, mathematics, and physical laws, the Greeks slowly adapted old ideas to fit into a less supernatural, hyper-rational universe.
As ancient peoples began to realize that sun, moon and stars follow certain rhythms in step with the seasons, they made the leap of thought to postulate that some conscious set of rules must be dictating these movements and seasonal changes which, for agrarian or pastoral societies, were a matter of life or starvation. Who or what could be causing these all-important changes to come about?
Certainly nothing on earth, no beast or human, had the power. Thus gods were born.
There are hints of the Greek conception of the universe in Homer, who mentions many subjects on his two epics describing war and the perils of trying to come home after long absence.
For Homer, heaven is a solid inverted bowl straddling the Earth, with fiery, gleaming either above the cloud-bearing air.
The fact that Hades is on the underside of earth has an important impact on conceptions of heaven: it is unlit by the sun (in Homer and in Hesiod), therefore, the sun--and by extension, other heavenly bodies - must sink only to the level of Ocean, which is as a river circling Earth's edge. From it the Sun must also rise -though how it gets back to the eastern bank of Ocean is never explained.
These popular conceptions of sky are more fully explained in Hesiod, whose works on gods and on agriculture and animal-herding are more closely connected to the practical application of astronomy.
He clocks spring, summer, and harvest by solstices and the rising and setting of certain stars, and notices that the sun migrates southwards in winter.
Night is a substance welling up from under the Earth, as if it were a dark flowing mist.

[Ragoo]

Famous astronomers of antiquity

* Anaxagoras
* Apollonius of Tyana
* Archimedes
* Archytas
* Aristaeus
* Aristillus
* Conon of Samos
* Democritus
* Empedocles
* Heraclides Ponticus
* Hicetas
* Hippocrates of Chios
* Macrobius
* Martianus Capella
* Menelaus of Alexandria (Menelaus theorem)
* Meton of Athens
* Parmenides
* Porphyry
* Posidonius
* Proclus
* Pythagoras
* Thales
* Theodosius of Bithynia

[Ragoo]

Ancient Greek astronomy

The Greeks were credited with several important discoveries in astronomy.
Aristarchus of Samos (310-230 B.C.) was the first to suggest that the earth revolved on an axis and moved around the sun. His ideas were not accepted until the 1500’s when Copernicus further developed the theory.

Another scientist, Hipparches (second century B.C.) believed the earth was the center of the universe.
He also discovered the constants of the equinoxes and the length of a year.

The Greek philosopher Anaxagoras discovered that the moon reflected the suns rays, instead of producing light itself. He discovered the causes of eclipses.
Thales of Miletus, was able to predict when a solar eclipse would occur.
Although scholars believe his prediction was a one-time event and was only approximate (some say he only predicted the year), the alleged feat added to his reputation as an astronomer.

[Ragoo]

Ancient Greek astronomy

Ancient Greek Astronomy, which also encompasses Roman astronomy, has its earliest references in the writings of Homer, and detailed a flat-earth viewpoint where the stars would rise and fall from the world-spanning ocean at different parts of the year.
It was used for astrology and fortune telling, and derived a great deal from the Babylonian Astronomy that came before it. The Greeks invented the "order of magnitude" system for determining the brightness of stars in 135 BC.
Our very term for celestial bodies, "planets" comes from the Greek word "planetes", meaning "wanderer", and the first ideas of a universe centered on something other than the Earth stem from Greek thought.
The five naked-eye visible planets were plotted against a combined solar and lunar calendar by the Greeks, and it was the Pythagoreans who eventually figured out that the Evening Star and the Morning Star were, in fact, the same wandering planet Venus.
The science of attempting to determine why the planets move the way they did dates back to ancient Greek Astronomy, and while Eudoxus' model (described above) was the root, it eventually branched out with more spheres, spheres that were slightly off center to one another, and planets that were on rotating circles on spheres that rotated as well – if this is making your head spin, you're not alone.
This attempt to mathematically describe how the planets moved was one of the brilliant attempts of the classical age, and is a good example of very smart people putting a lot of work into a detailed science, while missing one critical element – that the planets, including the Earth, rotate around the Sun.
It was in ancient Greek Astronomy that a sun centered cosmos was born. Aristarchus proposed a sun-centric model of the cosmos in the 3rd century BC, which was not well received. It wasn't until Copernicus, nearly 2,000 years later, that this idea gained acceptance.
Aristarchus also took the lengths of shadows of monuments to derive the curvature of the Earth – measuring the shadow length at noon on the summer solstice for a monument at Alexandria and another at Thebes.
From the differences in shadow lengths, and a little bit of experimentation, he was able to derive the degree of curvature of the Earth. By plugging in the distance between the two monuments, he was able to give a rough estimate of the size of the Earth. (Since his initial measurement for the distance between the two monuments was in error, his calculated size of the Earth was too small by almost 40%). He also used these same procedures to estimate the distance between the Sun and Earth, and the Moon and Earth in earth radii.
Unlike the Babylonians and Egyptians, ancient Greek Astronomy was mathematical, rather than religious in nature.
This view of Astronomy was profoundly important in the differentiation between Astronomy and astrology.
Greek astronomical thinking formed the foundation of much scientific and mathematical thought that laid the foundations for the world we live in today.

[Ragoo]

Ancient Indian Astronomy

Ancient Indian Astronomy

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from bharatpetroleum.com

Astronomy in Ancient India
Ancient India's contributions in the field of astronomy are well known and well documented.
The earliest references to astronomy are found in the Rig Veda, which are dated 2000 BC. During next 2500 years, by 500 AD, ancient Indian astronomy has emerged as an important part of Indian studies and its affect is also seen in several treatises of that period.
In some instances, astronomical principles were borrowed to explain matters, pertaining to astrology, like casting of a horoscope.
Apart from this linkage of astronomy with astrology in ancient India, science of astronomy continued to develop independently, and culminated into original findings, like:

1.The calculation of occurrences of eclipses
2.Determination of Earth's circumference
3.Theorizing about the theory of gravitation
4.Determining that sun was a star and determination of number of planets under our solar system

There are astronomical references of chronological significance in the Vedas.
Some Vedic notices mark the beginning of the year and that of the vernal equinox in Orion.
This was the case around 4500 BC. Fire altars, with astronomical basis, have been found in the third millennium cities of India.
The texts that describe their designs are conservatively dated to the first millennium BC, but their contents appear to be much older.

Ancient Indian Astronomy
Like many other branches of knowledge, the origins of the science of astronomy in India have to be traced back to the Vedas.
In the Vedic literature, Jyotisa is one of the six auxiliaries (shadangas) of the Vedic corpus of knowledge.
The six vedangas are

1.Siksa (phonetics)
2.Vyakarana (grammar)
3.Chandas (metrics)
4.Nirukta (etymology)
5.Jyotisa (astrolonomy and
6.Kalpa (rituals).

Indian Astronomers

1.Aryabhata -Aryabhata explicitly mentioned that the earth rotates about its axis, thereby causing what appears to be an apparent westward motion of the stars. Aryabhata also mentioned that reflected sunlight is the cause behind the shining of the moon.
2.Brahmagupta -Brahmasphuta-siddhanta (Correctly Established Doctrine of Brahma, 628 CE) dealt with both Indian mathematics and astronomy. Bahmagupta also calculated the instantaneous motion of a planet, gave correct equations for parallax, and some information related to the computation of eclipses. His works introduced Indian concept of mathematics based astronomy into the Arab world.
3.Varahamihira -Varahamihira was an astronomer and mathematician who studied and Indian astronomy as well as the many principles of Greek, Egyptian, and Roman astronomical sciences.
4.Bhaskara I -Authored the astronomical works Mahabhaskariya (Great Book of Bhaskara), Laghubhaskariya (Small Book of Bhaskara), and the Aryabhatiyabhashya (629 CE)—a commentary on the Āryabhatīya written by Aryabhata. Hayashi (2008) writes 'Planetary longitudes, heliacal rising and setting of the planets, conjunctions among the planets and stars, solar and lunar eclipses, and the phases of the Moon are among the topics Bhaskara discusses in his astronomical treatises.
5.Lalla -Author of the Sisyadhivrddhida (Treatise Which Expands the Intellect of Students), which corrects several assumptions of Aryabhata. The Sisyadhivrddhida of Lalla itself is divided into two parts:Grahadhyaya and Goladhyaya. Grahadhyaya (Chapter I-XIII) deals with planetary calculations, determination of the mean and true planets, three problems pertaining to diurnal motion of Earth, eclipses, rising and setting of the planets, the various cusps of the moon, planetary and astral conjunctions, and complementary situations of the sun and the moon. The second part—titled Goladhyaya (chapter XIV–XXII)—deals with graphical representation of planetary motion, astronomical instruments, spherics, and emphasizes on corrections and rejection of flawed principles.
6.Bhaskara II - Authored Siddhantasiromai (Head Jewel of Accuracy) and Karaakutuhala (Calculation of Astronomical Wonders) and reported on his observations of planetary positions, conjunctions, eclipses, cosmography, geography, mathematics, and astronomical equipment used in his research at the observatory in Ujjain, which he headed.
7.Sripati -Sripati was a astronomer and mathematician who followed the Brhmagupta school and authored the Siddhantasekhara (The Crest of Established Doctrines) in 20 chapters, thereby introducing several new concepts, including moon's second ineuqlity.
8.Mahendra Suri -The 182 verse Yantra-raja mentions the astrolabe from the first chapter onwards, and also presents a fundamental formula along with a numerical table for drawing an astrolabe although the proof itself has not been detailed. Longitudes of 32 stars as well as their latitudes have also been mentioned. Mahendra Suri also explained the Gnomon, equatorial co-ordinates, and elliptical co-ordinates.The works of Mahendra Suri may have influenced later astronomers like Padmanabha (1423 CE)—author of the Yantra-raja-adhikara, the first chapter of his Yantra-kirnavali.
9.Nilakanthan Somayaji -Nilakanthan Somayaji, in his Aryabhatiyabhasya, a commentary on Aryabhata's Aryabhatiya, developed his own computational system for a partially heliocentric planetary model, in which Mercury, Venus, Mars, Jupiter and Saturn orbit the Sun, which in turn orbits the Earth, similar to the Tychonic system later proposed by Tycho Brahe in the late 16th century. Nilakantha's system, however, was mathematically more effient than the Tychonic system, due to correctly taking into account the equation of the centre and latitudinal motion of Mercury and Venus. Most astronomers of the Kerala school of astronomy and mathematics who followed him accepted his planetary model.

[Ragoo]

Hindu Astronomy

The Hindu Astronomy is one of the ancient astronomical systems of the world.
It is sometimes considered a controversial subject, because some scholars argue that it shows a higher antiquity of the Vedic culture as generally assumed.

The astronomy and the astrology of India are based upon sidereal calculations.
The sidereal astronomy is based upon the stars and the sidereal period is the time that it takes the object to make one full orbit around the Sun, relative to the stars.
This is considered to be an object's true orbital period.
In Hindu Astronomy, the vernal equinox (the First Point of Aries) is often calculated at 23° from 0° Aries (1950 CE), i.e. about 7° Pisces (Frawley 1991:148).
The constellation that marks this vernal equinox is the Uttarabhadra.

In the time of the Puranas, the vernal equinox was marked by the Ashwini constellation (beginning of Aries), which gives a date of about 300-500 CE.

The Vishnu Purana (2.8.63) states that the equinoxes occur when the Sun enters Aries and Libra, and that when the sun enters Capricorn, his northern course (from winter to summer solstice) commences, and the southern course when he enters Cancer.

Ancient Indian Astronomy .nava.jpg (39.58 KiB) Viewed 64 times

In the Suryasiddhanta, the rate of precession at 54" (it actually is 50.3"), which is much more accurate than the number calculated by the Greeks (Frawley 1991:148).

The Hindus use a system of 27 or 28 Nakshatras (lunar constellations) to calculate a month. Each month can be divided into 30 lunar tithis (days). There are usually 360 or 366 days in a year.

The Hindu astronomer Varahamihira, Garga (quoted by Somakara), the Mahabharata and the Vedanga Jyothish refer to the constellation Dhanishta (Shravishta) and thus to an ancient calendar that would have been used in 1280 BCE (see Frawley 1991: 152 ff.).

The Kaushiktaki Brahmana and possibly the Atharva Veda refer to a similar calendar (Frawley 1991).

The Atharva Veda, the Tandya Mahabrahmana and Laughakshi (quoted by Somakara) may show knowledge of an earlier calendar, but still in the Magha constellation (Frawley 1991).In still earlier Hindu calendars, the vernal equinox was in the Krittika constellation.

There are additionally references to the summer solstice in the Magha constellation.

This could indicate a date around 2000 BCE. The Atharva Veda, the Taittiriya Brahmana, the Shatapahta Brahmana, the Maitriyani Upanishad and the Vishnu Purana show such a constellation in the Krittika (Frawley 1991).

In the working out of horoscopes (called Janmakundali), the position of the Navagrahas, nine planets plus Rahu and Ketu (mythical demons, evil forces) was considered.
The Janmakundali was a complex mixture of science and dogma. But the concept was born out of astronomical observations and perception based on astronomical phenomenon. In ancient times personalities like Aryabhatta and Varahamihira were associated with Indian astronomy.

It would be surprising for us to know today that this science had advanced to such an extent in ancient India that ancient Indian astronomers had recognized that stars are same as the sun, that the sun is center of the universe (solar system) and that the circumference of the Earth is 5,000 Yojanas.
One Yojana being 7.2 kms., the ancient Indian estimates came close to the actual figure.

[Ragoo]

Ancient Astronomy.Ancient Indian Astronomy

India's Contribution to Astronomy

Astronomy is one area which has fascinated all mankind from the beginnings of history.
In India the first references to astronomy are to be found in the Rig Veda which is dated around 2000 B.C. Vedic Aryans in fact deified the Sun, Stars and Comets.
Astronomy was then interwoven with astrology and since ancient times Indians have involved the planets (called Grahas) with the determination of human fortunes.
The planets Shani, i.e. Saturn and Mangal i.e. Mars were considered inauspicious.

In the working out of horoscopes (called Janmakundali), the position of the Navagrahas, nine planets plus Rahu and Ketu (mythical demons, evil forces) was considered.
The Janmakundali was a complex mixture of science and dogma.
But the concept was born out of astronomical observations and perception based on astronomical phenomenon.
In ancient times personalities like Aryabhatta and Varahamihira were associated with Indian astronomy.

It would be surprising for us to know today that this science had advanced to such an extent in ancient India that ancient Indian astronomers had recognised that stars are same as the sun, that the sun is center of the universe (solar system) and that the circumference of the earth is 5000 Yojanas. One Yojana being 7.2 kms., the ancient Indian estimates came close to the actual figure.

Aryabhatta's Magnum Opus, the Aryabhattiya was translated into Latin in the 13th century.
Through this translation, European mathematicians got to know methods for calculating the areas of triangles, volumes of spheres as well as square and cube root.
Aryabhatta's ideas about eclipses and the sun being the source of moonlight may not have caused much of an impression on European astronomers as by then they had come to know of these facts throught the observations of Copernicus and Galileo.

But considering that Aryabhatta discovered these facts 1500 years ago, and 1000 years before Copernicus and Galileo makes him a pioneer in this area too. Aryabhatta's methods of astronomical calculations expounded in his Aryabhatta-siddhanta were reliable for practical purposes of fixing the Panchanga (Hindu calendar).
Thus in ancient India, eclipses were also forecast and their true nature was perceived at least by the astronomers.

The lack of a telescope hindered further advancement of ancient Indian astronomy.
Though it should be admitted that with their unaided observations with crude instruments, the astronomers in ancient India were able to arrive at near perfect measurement of astronomical movements and predict eclipses.

Indian astronomers also propounded the theory that the earth was a sphere.
Aryabhatta was the first one to have propounded this theory in the 5th century.
Another Indian astronomer, Brahmagupta estimated in the 7th century that the circumference of the earth was 5000 yojanas. A yojana is around 7.2 kms. Calculating on this basis we see that the estimate of 36,000 kms as the earth's circumference comes quite close to the actual circumference known today.

[*BaccA*]

Ok.
I`d like to tell about Ancient Arab Astronomy

Ancient Arab Astronomy


by Robin Westgate, Teacher
English Speaking School, Al Ain

Throughout history man has expressed an affinity for knowledge relating to his physical and universal environment. Inevitably such curiosity has also encouraged and given rise to the construction of cosmologies based upon concepts, idiosyncratic or otherwise, extrapolated from observation and deduction.

The historic cultures that have deviated from or omitted such intellectual processes are atypical.
Man’s quest to describe the mechanisms and laws governing the cosmos has dictated and inexorable drive towards achieving an understanding of it.

The reasons for this are various but unified: the need to discover underlying truths and reasons for existence are common to the fields of theology, philosophy and metaphysics, not to mention pure scientific enquiry.
All these fields of thought have played their part in initiation man’s cognitive research into his environment, with the ultimate aim of reducing the Universe to rational and reasonable principles, sub specie aeternitatis.

In the context of this article I have endeavored to provide a background of astronomical knowledge as a function of time, form the beginnings of recorded history (c.4000 BC) until the time of the ascendancy of Muslim cultures.

Such an approach seems necessary in any discussion involving the relative contributions made by any particular peoples, so that the linear or even exponential progression land development of concepts or inventions can be seen to be integrated into the overall historical continuum.

However, to be realistic, the provision of a full treatment of historical astronomical issues, by each contributing culture, would prove exhaustive an irrelevant to an examination of Muslim values.
Accordingly, the descriptions given should be regarded as summaries of earlier achievements, rather than complete and definitive accounts of preceding methods and philosophies.




Ancient Arab Astronomy


Apart from its historical interest, the aim of this article is to demonstrate how any one culture may contribute- consciously or not – to the historical progression of scientific and philosophic concepts.

I have tried to indicate this aspect by describing how the Muslims relied heavily upon the literature of preceding civilizations – especially those of classical Greece and India in order to prepare the foundations of their own ideas and requirements.
The ensuing developments in the Arab world are then examined in their own right.

Finally, the subsequent link in the historical continuum (specifically the transfer of Arab knowledge into Western Europe at the time of the Crusades) is briefly covered to preserve the chronological sense and structure.

I hope that I have succeeded in showing that the Arab development of astronomical methods and concepts was by no means a negligible one. Rather, theirs was splendid achievement that helped preserve and unify early mediaeval scientific knowledge for posterity.
The Arabs once ruled an empire that stretched from central Asia to Spain.
This empire reached its zenith between the eighth and thirteenth centuries AD. Arab scholars of that period knew more about science and the arts than any other contemporary peoples.
They also translated many classical (Greco-Roman) works of literature and science.

In fact generally speaking the Muslims were very interested in books and learning. Rhazes (al Razi-C. ninth century), Vienna (Ibn Sina-c. tenth century) and Averroes (1126-1198) were among the best known of Muslim philosophers.
They studied the great Greek writers, particularly Plato and Aristotle.
Their goal seems to have been (perhaps rather surprisingly) to try to find ways to reconcile the ideas of the ancient Greeks with the teachings of Islam.

Consequently, universities were established in the leading Muslim cities of Baghdad, Damascus, Jerusalem, Alexandria, Cairo and Cordoba.
Further, the book business flourished. In universities, palaces and the homes of wealthy merchants could be found large and impressive libraries.
By 1250 AD the most valuable material in Islamic libraries had become available to European scholars in translation.

The latter point was of great historical importance; eventually much of the scientific knowledge that the Muslims had gathered from the ancient classical world and from India was passed to the west, through Spain and southern Italy, around the time of the Crusades.
At that time most European scholars realized the tremendous scientific and technological superiority of the Islamic world. And eagerly sought translations of Muslim works.

Thus these Greek and Arab writings that flowed into Europe, especially after the beginning of the twelfth century, made up a rich legacy of scientific and philosophical knowledge.
For example, Arabic (Hindi) numerals and the zero symbol made possible a decimal system of computation.
Also, Euclidean geometry, together with algebra and trigonometry from the Arab world, greatly increased the scope and accuracy of mathematics, especially useful for later astronomical applications during and after the Renaissance.

This transfer of information occurred just in time, for from about 1350 onwards, the Mongols in the east and the Christians in Spain began systematically to destroy Islamic books in a wholesale manner, as part of their anti-Muslim wave of feeling at that time

Fortunately, a large number of Islamic books survived in Egypt, Persia and India, from where most of our knowledge of Muslim civilization has originated. As a result, every present-day intellectual disciple owes a debt to the scientific heritage of Islam.

Arab Astronomy and Navigation

Astronomy

Muslim scholars made significant contributions towards the development of many ‘modern’ sciences, such as physics, chemistry, medicine, mathematics and astronomy. They were particularly interested in the latter.

Using the work of the second century Greek astronomer Ptolemy as a basis, Muslim thinkers greatly increased man’s knowledge of astronomy. Indeed, during the Middle Ages, when European science underwent a decline, it was the Arabs who preserved the astronomical heritage.

In some respects this achievement may have been inevitable, since knowledge of the stars was essential for navigational purposes and for telling the times of prayers and religious festivals. In other words, being adventurous traders and mariners and temporally precise worshippers, the Arabs needed to study astronomy other than for its purely scientific interest, though undoubtedly such an interest existed. Consequently they constructed many observatories and improved certain measuring instruments such as the astrolabe for determining and recording the positions and movements of celestial bodies.

Foremost amongst early Arab scientists was al Khawarzimi, who lived in Baghdad during the ninth century. His work was mainly concerned with astronomy and mathematics. In fact, his mathematical treatise was the first to employ what westerners term ‘Arabic numerals’ (which were really borrowed from the Indians, as explained earlier. Although it seems most likely that the Indians invented the zero symbol or cipher (‘sifr’ means empty in Arabic), al Khwarzimi is attributed with greatly developing its use n mathematics to simplify multiplication and division. He also gave a systematic account of algebra and geometry, for use in solving practical astronomical and navigational problems.

Other notable Arab astronomers were al Battam (d. 929), al Zarquli (d. 1087) and Omar al Khayyami (d. 1123). The latter was a Persian mathematician who devised a very accurate calendar based on astronomical observations. It was reputed to have been more accurate than the Gregorian one we use today, with an error factor of only one day in 3770, rather than the Gregorian’s one in 33303.

Incidentally, the mathematics used for astronomical calculations by the Arabs involved the use of degrees and minutes of arc-first developed by the Sumerians, and later developed extensively by the Babylonians, millennia earlier. The direct expansion and inclusion of this system into Euclidean geometry is the main reason why we measure angles in degrees, minutes and seconds nowadays (not to mention basing our system of measuring time upon it also).

Arab interest in astronomy was also continued in Moghul India, where massive observatories were built in Jaipur, for example. It is interesting to consider that some modern historians think that the writings of the great Copernicus (who was the first westerner to propose an heliocentric planetary system) show much that could be attributable to these early Muslim astronomers.
Navigation

When the first Portuguese navigators, like Vasco da Gama, sailed along the East African coast and around the Arabian Peninsula they encountered a well-established Arab seafaring tradition, utilizing an advanced navigational science dating from the eighth century. Techniques used were basically simple, but never the less by the eleventh century Arab mariners had adapted the Chinese discovery of the magnetic properties of lodestone for use as a compass at sea. Earlier methods had relied on steering by Polaris, the ‘North’ star, and ‘Kamal’, a kind of simple astrolabe used to reckon relative latitude. In fact, it is believed that Europeans first acquired a knowledge of the magnetic compass and the astrolabe (later to become the sextant) from Muslim sailors.

The renowned Arab navigator Shihab al Ahmed bin Majid al Najdi (c.1500), at the height of Arab navigational prowess, wrote a masterpiece entitled “the Book of Profitable Things concerning the First Principles and Rules of Navigation” which featured much astronomical observational data, amongst other things nautical.

Part of the legacy of this period include the fact that many of the brightest stars still bear Arabic names, allocated to them by Arab astronomers and navigators, for example Betelgeuse, Deneb, Aldebaran and Altair. These names, along with numerous other facets of Arab scientific nomenclature and mathematics, passed into Europe during the Renaissance.

However, this period, marked by the ‘collision’ of two great maritime powers – the European and the Arabian – was the beginning of the era of European ascendancy and the decline of Arab commercial dominance in Middle Eastern and Oriental seas.

[*BaccA*]

Ancient Arab Astronomy

Here ( http://www.articlesbase.com/science-art ... 36221.html) interesting article "Contributions of Ancient Arabian and Egyptian Scientists on Astronomy"
Md. Wasim Aktar
Deptt. of Agril. Chemicals, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, West Bengal, India.

Astronomy (‘Ilm al-Hay’ah) or the science of formation (i.e. of the heavens) deals with such things as the structure of the heavens, the number and configuration of the stars, the signs of the zodiac, the distances of the stars, their size and their motions.
It also deals with the compilation of planetary tables, the catalogue of stars for the making of calendars and similar tasks.

[*BaccA*]

ARAB CONTRIBUTIONS TO CIVILIZATION
The years between the seventh and thirteenth centuries mark a period in history when culture and learning flourished in North Africa, Asia, Southern Europe, and the Middle East.
When one sets aside the vagaries of politics, intrigue, mistrust, and suspicion which have plagues Man’s history, one finds that the Arab world continue to spin out the thread of earliest recorded civilization.
It enhanced and developed the arts and sciences and preserved the libraries of the early centuries of the Greek, Roman, and Byzantine cultures. Indeed, during the Dark Ages of Europe, much learning was preserved for the world through the Arab libraries in the universities of Morocco (Fez), Mali (Timbuktu) and Egypt (al-Azhar).
From this period of Arab influence, new words such as orange, sugar, coffee, sofa, satin, and algebra filtered into the languages of Europe and eventually into our own. New discoveries were made in the sciences and arts which improved the life and condition of Man, and thousands of Arab contributions have become an integral part of human civilization.

ASTRONOMY

The astrolabe was improved with religion in mind.
It was used to chart the precise time of sunrises and sunsets, and to determine the period for fasting during the month of Ramadan, Arab astronomers of the Middle Ages compiles astronomical charts and tables in observatories such as those at Palmyra and Maragha.
Gradually, they were able to determine the length of a degree, to establish longitude and latitude, and to investigate the relative speeds of sound and light.
Al-Biruni, considered one of the greatest scientists of all time, discussed the possibility of the earth’s rotation on its own axis – a theory proven by Galileo six centuries later.
Arab astronomers such as al-Fezari, al-Farghani, and al-Zarqali added to the works of Ptolemy and the classic pioneers in the development of the magnetic compass and the charting of the zodiac.
Distinguished astronomers from all over the world gathered to work at Maragha in the thirteenth century.

[*BaccA*]

Copernicus and Arabic Astronomy: A Review of Recent Research

On occasion of the 464th anniversary of the death of Copernicus.
www.muslimheritage.com

......Based on recent manuscript discoveries, these works argue that Islamic science produced astronomical theories of the highest order. These theories were surveyed and their possible ways of transmission were depicted in detail. Taken together, the primary texts, and the interpretive essays that highlighted them, have revealed very extensive similarities between the mathematics that was used by Copernicus to develop his theories and the mathematics that was used by mathematical astronomers of the Islamic world some two to three hundred years before. In some instances, as in the case of the model for the motion of the planet Mercury, it was found that Copernicus even made mistakes in his interpretation of the earlier mathematical model that he apparently inherited from the works of the Damascene astronomer Ibn al-Shatir (d. 1375). In other instances he remained faithful to the mathematical formulations that were developed by other astronomers of the Islamic world such as Mu'ayyad al-Din al-'Urdi (d. 1266) and Nasir al-Din al-Tusi (d. 1274).

[Dina]

good posts.
You all cool

[Dina]

I see there is no articles about Ancient Egyptian Astronomy.

As in most early cultures, the patterns and behaviors of the sky led to the creation of a number of myths to explain the astronomical phenomena. For the Egyptians, the practice of astronomy went beyond legend: huge temples and pyramids were built to have a certain astronomical orientation.
The Ancient Egyptians started in the worship stage and eventually began to see how astronomy could help them in their everyday lives.

Achievements of Ancient Egyptian Astronomy

Achievements of Ancient Egyptian Astronomy.
1. 2400 BC. - Astronomical Calendar
2. Alexandria University - Ptolemaic Period scientists reached solid conclusions on the earth's rotation around the sun and the approximate geosphere of the planet
3.238 BC. - Ptolemy III suggested adding one day every four years to calendar - implemented two centuries later under Julius Caesar and known as the Julian calendar.

[Dina]

Also I`ve found good forum . http://www.egyptologyonline.com/astronomy.htm