APOD: Dunhuang Star Atlas (2009 June 19)

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APOD: Dunhuang Star Atlas (2009 June 19)

Post by DavidACaruso » Fri Jun 19, 2009 5:54 am

I read the description of this, the "oldest complete star atlas known," with disbelief. It makes it sound like this, a somewhat crude map sketched by hand, represents the extent of ancient (less than 1500 years?) knowledge about the stars. The ignorance of the author is stunning when you consider the archeological evidence for the profound knowledge possessed by ancient Egyptian sages and astronomers. The alignments and positioning of their temples and monuments, the accuracy of their calendar (superior to ours, as it takes into account not just the cycles of the Sun and moon, but also, more importantly, of Sirius), among other things, shows great and complete knowledge. Though they did not fly in airplanes or spaceships, they knew the size of the Earth and their exact position on it. Modern scientist by and large have a great bias with regards their own knowledge and tend to dismiss the ancient scientists, though the evidence they left behind of their knowledge deserves better.

http://apod.nasa.gov/apod/ap090619.html

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Re: Old Star Atlas (APOD June 19)

Post by neufer » Fri Jun 19, 2009 11:06 am

DavidACaruso wrote:I read the description of this, the "oldest complete star atlas known," with disbelief. It makes it sound like this, a somewhat crude map sketched by hand, represents the extent of ancient (less than 1500 years?) knowledge about the stars. The ignorance of the author is stunning when you consider the archeological evidence for the profound knowledge possessed by ancient Egyptian sages and astronomers. The alignments and positioning of their temples and monuments, the accuracy of their calendar (superior to ours, as it takes into account not just the cycles of the Sun and moon, but also, more importantly, of Sirius), among other things, shows great and complete knowledge. Though they did not fly in airplanes or spaceships, they knew the size of the Earth and their exact position on it. Modern scientist by and large have a great bias with regards their own knowledge and tend to dismiss the ancient scientists, though the evidence they left behind of their knowledge deserves better.
What ancient Egyptian sages and astronomers knew or did not know is mostly idle speculation.
(As is what ancient Dogon "sages and astronomers" knew or did not know about Sirius B.)

The Chinese left us invaluable documents about eclipses, comets, supernova, sunspots and the positions of 1,300 stars :
http://sunearthday.nasa.gov/2008eclipse/ancienteclipses.php wrote:
<<By 2300 BC, ancient Chinese astrologers already had sophisticated observatory buildings, and as early as 2650 BC, Li Shu was writing about astronomy. According to historical records, a total of 27 observatories were built in the Yuan Dynasty but only the one in Dengfeng is known to have survived. Gaocheng Observatory is the oldest facility of its kind in China. The observatory dates to the early portion of the Yuan Dynasty (1271-1368 AD).

Established in 1279 AD by the famous astronomer Guo Shoujing, it was designed originally for use in predicting the time of the solstice each year. Astronomers at the site were able to calculate the actual length of the year to 365.2425 days some 300 years before Europeans managed to develop the Gregorian calendar.

Chinese Firsts:

Although total solar eclipses were a cause for alarm and ill-omen, lunar eclipses were not feared by the people because they were so commonly seen. As a matter of fact the earliest recording of one was not until 1065 BC. Before this time, the event was only slightly mysterious. Lunar eclipse had weak astrological meaning in ancient China, so systematic records began from up to the 5th century. There were 545 records before 1500 AD in which 78 reported a total eclipse; 54 timed to the maximum or the contacts, 39 recorded maximum magnitude.

They were the first to spot Halley's Comet in 240 BC. As the "broom star" on the handle of Yin. But in the 613 BC Spring and Autumn Annals ( 春秋 Chūnqiū) of Confucius, he noted that "In July, there was a comet that entered the Big Dipper." ("秋七月,有星孛入于北斗。" qiū qīyuè, yǒu xīng1bèi rù yú běi3d ǒu).

The Mawangdui silk, a sketch book of cometary forms and the disasters associated with them, was compiled ca 300 B.C., but the knowledge it encompasses is believed to date as far back as 1500 B.C. Comets had been recorded, and drawn since the Shang Dynasty (1600 - 1046 BC).

The Chinese developed a system of 283 constellations, with identifies based upon natural objects rather than deities and historical figures as was the style of the Ancient Greeks. Constellations were called palaces, and the brightest star was the Emperor Star, with the fainter stars being the Princes. A constellation was called a "palace," with the major star being the emperor star and lesser stars being princes. The Fourth Century astronomer Shih-shen catalogued 809 stars among these constellations, but without any surviving sketches or sky maps, we an exact identification of these constellations is impossible from the earliest history of Chinese observations.

We know that they called the North Star, Bei Ji, and eventually created star maps. In the famous Dunhuang star map of 700 AD. This map is thought to date from the reign of Emperor Zhongzong of Tang (705-710 AD), founded in Dunhuang. The Dunhuang manuscript is the oldest surviving star map in the world. Ursa Major, Sagittarius and Capricornus are recognizable. The three colors (white, black and yellow) indicate the schools of astronomy of Shih Shen, Kan Te, and Wu Hsien. The whole set of star maps contained 1,300 stars.

They also noted sunspots as they would be infrequently observed when the sun was near the horizon and could be safely viewed through atmospheric absorption. No sketches of these sightings survives, although numerous written recordings have been found dating from ca 28 BC and later. The earliest mention may have been by an early astronomer Gan De (ca 500 BC). A sighting was also noted in the 165 BC encyclopedia The Ocean of Jade, of a figure identified as wang that appeared on the sun; a symbol like a cross with bars drawn across the top and bottom. By May 10, 28 BC, sunspots were noted in the official Imperial histories of China. Between 28 BC and 1638 AD, the historian Joseph Needham (1900-1995) identified 112 sightings in these records during the time before telescopic observations began in the West starting with Galileo in 1609.>>
------------------------------------------------------
http://www.earthview.com/ages/history.htm wrote:
<<The earliest record of a solar eclipse comes from ancient China. The date of this eclipse, usually given as October 22, 2134 B.C., is not certain. Historians know the account was written sometime within a period of about two hundred years. During that time there were several total eclipses visible in China. The 2134 B.C. eclipse is simply the best guess. The ancient Chinese document Shu Ching records that "the Sun and Moon did not meet harmoniously." The story goes that the two royal astronomers, Hsi and Ho, had neglected their duties and failed to predict the event. Widespread Oriental belief held that an eclipse was caused by an invisible dragon devouring the Sun. Great noise and commotion (drummers drumming, archers shooting arrows into the sky, and the like) were customarily produced to frighten away the dragon and restore daylight. When this eclipse took place, the emperor was caught unprepared. Even though the Sun returned, the angry ruler ordered the astronomers beheaded!>>
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http://www.astronomy.com/asy/default.aspx?c=a&id=2295 wrote:
<<Until the mid-1400s, the Chinese made the most detailed and complete observations of comets. As early as 200 b.c., they employed official skywatchers to record and interpret any new omens in the heavens. These officials recognized, some nine centuries before their European counterparts, that comet tails always point away from the Sun. The Chinese interest in comets, however, was for their astrological importance as signs of coming change.>>
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http://en.wikipedia.org/wiki/History_of ... bservation

<<In 185 CE, Chinese astronomers recorded the appearance of a bright star in the sky, and observed that it took about eight months to fade from the sky. It was observed to sparkle like a star and did not move across the heavens like a comet. These observations are consistent with the appearance of a supernova, and this is believed to be the oldest recorded by humankind. SN 185 may have also possibly been recorded in Roman literature, though no records have survived. The gaseous shell RCW 86 is suspected as being the remnant of this event, and recent X-ray studies show a good match for the expected age.

In 393 CE, the Chinese recorded the appearance of another "guest star", SN 393, in the modern constellation of Scorpius. Additional unconfirmed supernovae events may have been observed in 369 CE, 386 CE, 437 CE, 827 CE and 902 CE. However these have not yet been associated with a supernova remnant, and so they remain only candidates. Over a span of about 2,000 years, Chinese astronomers recorded a total of twenty such candidate events, including later explosions noted by Islamic, European and possibly Indian and other observers.

The supernova SN 1006 appeared in the southern constellation of Lupus during the year 1006 CE. This was the brightest recorded star ever to appear in the night sky, and its presence was noted in China, Egypt, Iraq, Italy, Japan and Switzerland. It may also have been noted in France, Syria and North America. Egyptian physician, astronomer and astrologer Ali ibn Ridwan gave the brightness of this star as one-quarter the brightness of the Moon. Modern astronomers have discovered the faint remnant of this explosion and determined that it was only 7,100 light-years from the Earth.

Supernova SN 1054 was another widely-observed event, with Arab, Chinese and Japanese astronomers recording the star's appearance in 1054 CE. It may also have been recorded by the Anasazi as a petroglyph. This explosion appeared in the constellation of Taurus, where it produced the Crab Nebula remnant. At its peak, the luminosity of SN 1054 may have been four times as bright as Venus, and it remained visible in daylight for 23 days and was visible in the night sky for 653 days.

There are fewer records of supernova SN 1181, which occurred in the constellation Cassiopeia just over a century after SN 1054. It was noted by Chinese and Japanese astronomers, however. The pulsar 3C58 may be the stellar relic from this event.>>
------------------------------------------------------
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Re: Old Star Atlas (APOD June 19)

Post by bystander » Fri Jun 19, 2009 1:10 pm

DavidACaruso wrote:I read the description of this, the "oldest complete star atlas known," with disbelief. It makes it sound like this, a somewhat crude map sketched by hand, represents the extent of ancient (less than 1500 years?) knowledge about the stars. The ignorance of the author is stunning when you consider the archeological evidence for the profound knowledge possessed by ancient Egyptian sages and astronomers. The alignments and positioning of their temples and monuments, the accuracy of their calendar (superior to ours, as it takes into account not just the cycles of the Sun and moon, but also, more importantly, of Sirius), among other things, shows great and complete knowledge. Though they did not fly in airplanes or spaceships, they knew the size of the Earth and their exact position on it. Modern scientist by and large have a great bias with regards their own knowledge and tend to dismiss the ancient scientists, though the evidence they left behind of their knowledge deserves better.
Why stop with the Egyptians? How about the Mayans, or even the most ancient known civilization, the Sumerians? Besides, as neufer pointed out, the Chinese had ancient knowledge of the stars, perhaps even predating the Egyptians. That doesn't change that this is the oldest known star map, and complete, in that it is a full 360 degree. And crude, hand drawn? What did you expect, computer generated graphics? I think you owe an apology to the author.

From The Smithsonian / NASA Astrophysics Data System Libraries:
The Dunhuang Chinese Sky: A comprehensive study of the oldest known star atlas
Journal of Astronomical History and Heritage (ISSN 1440-2807), Vol. 12, No. 1, p. 39 - 59 (2009).

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Re: Old Star Atlas (APOD June 19)

Post by Chris Peterson » Fri Jun 19, 2009 1:35 pm

DavidACaruso wrote:I read the description of this, the "oldest complete star atlas known," with disbelief. It makes it sound like this, a somewhat crude map sketched by hand, represents the extent of ancient (less than 1500 years?) knowledge about the stars. The ignorance of the author is stunning when you consider the archeological evidence for the profound knowledge possessed by ancient Egyptian sages and astronomers.
I didn't read anything that led me to your interpretation. There is nothing suggesting that other civilizations, including more ancient ones, didn't have excellent knowledge of the stars. This is simply described as "one of the most impressive documents in the history of astronomy". How can you disagree with that?

Most of what we know about older cultures' knowledge of the sky is arrived at indirectly- by architectural alignments, literary references, and other archaeological inferences. The Sumerians and Egyptians didn't leave any complete star atlases for us to find. That's what makes this ancient document so interesting.
Chris

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Re: Old Star Atlas (APOD June 19)

Post by Chris Peterson » Fri Jun 19, 2009 1:43 pm

bystander wrote:Why stop with the Egyptians? How about the Mayans, or even the most ancient known civilization, the Sumerians?
Peculiar wording, perhaps unintended?

Compared with Egyptian or Sumerian astronomy, Mayan developments are recent- roughly contemporaneous with the Chinese document in today's APOD. The peak of Mayan culture occurred only about 1000 years ago.
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Re: Old Star Atlas (APOD June 19)

Post by bystander » Fri Jun 19, 2009 2:20 pm

Chris Peterson wrote:Compared with Egyptian or Sumerian astronomy, Mayan developments are recent- roughly contemporaneous with the Chinese document in today's APOD. The peak of Mayan culture occurred only about 1000 years ago.
Compared to the Sumerians, the Mayans are indeed recent, as are the Egyptians. The Mayan calandar dates back to 3114 BC, contemporaneous with dynastic Egypt and ancient China, with pre-classic ruins dating back to 3rd millenium BCE. Classic Mayan civilization (1st millenium CE) is indeed contemporaneous with Dunhuang Star Atlas.

The wording may have been peculiar. I didn't mean to imply that Maya preceded Egypt, only that Egypt was not the only ancient civilization to study the stars. I did, however, mean to imply Sumer preceded Egypt.
Donovan wrote:
The continent of Atlantis was an island
which lay before the great flood
in the area we now call the Atlantic Ocean.
So great an area of land, that from her western shores
those beautiful sailors journeyed
to the South and the North Americas with ease,
in their ships with painted sails.

To the East, Africa was a neighbour, across a short strait of sea miles.
The great Egyptian age is but a remnant of The Atlantian culture.
The antediluvian kings colonised the world.
All the Gods who play in the mythological dramas
in all legends from all lands were from fair Atlantis.

Knowing her fate, Atlantis sent out ships to all corners of the Earth.
On board were the Twelve:
The poet, the physician, the farmer, the scientist,
the magician and the other so-called Gods of our legends.
Though Gods they were -
And as the elders of our time choose to remain blind
let us rejoice and let us sing and dance and ring in the new.

Hail Atlantis!

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Dunhuang Star Atlas

Post by shawndougherty » Fri Jun 19, 2009 4:43 pm

Does anyone know where one can buy a poster or print of the Dunhuang Star Atlas (APOD 6/19/09). Very beautiful and interesting. Thanks.

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Mayan water monster Oannes

Post by neufer » Fri Jun 19, 2009 5:05 pm

bystander wrote:I didn't mean to imply that Maya preceded Egypt, only that Egypt was not the only
ancient civilization to study the stars. I did, however, mean to imply Sumer preceded Egypt.
Sumer was, in turn, preceded by the Mayan water monster Oannes: :wink:
------------------------------------------------
http://en.wikipedia.org/wiki/Ancient_astronauts wrote:
<<In their 1966 book Intelligent Life in the Universe astrophysicists I.S. Shklovski and Carl Sagan devote a chapter to arguments that scientists and historians should seriously consider the possibility that extraterrestrial contact occurred during recorded history. Shklovski and Sagan cited tales of Oannes, a fishlike being attributed with teaching agriculture, mathematics and the arts to early Sumerians, as deserving closer scrutiny as a possible instance of paleocontact due to its consistency and detail.

Image

In his 1979 book Broca's Brain, Sagan suggested that he and Shklovski might have inspired the wave of '70s ancient astronaut books, expressing disapproval of "von Daniken and other uncritical writers" who seemingly built on these ideas not as guarded speculations but as "valid evidence of extraterrestrial contact." Sagan also reiterated his earlier conclusion that extraterrestrial visits to Earth were possible but unproven, and perhaps improbable.>>
------------------------------------------------
http://en.wikipedia.org/wiki/Oannes#As_Oannes wrote:
<<Oannes was the name given by the Babylonian writer Berossus in the 3rd century BC to a mythical being who taught mankind wisdom. Berossus describes Oannes as having the body of a fish but underneath the figure of a man. He is described as dwelling in the Persian Gulf, and rising out of the waters in the daytime and furnishing mankind instruction in writing, the arts and the various sciences.

Image

Once thought to be based on the ancient Babylonian god Ea, it is now known that Oannes is in fact based on Uan (Adapa) - the first of the seven antediluvian sages or Abgallu (in Sumerian Ab=water, Gal=Great, Lu=man), who were sent by Ea to deliver the arts of civilization to mankind in ancient Sumerian mythology, at Eridu, the oldest city of Sumer.

Some scholars suggest the Abgallu were seafarers aboard a ship from the Indus River Valley/Mohenjo Daro civilization comparable in age to ancient Sumer and has some identified parallels to the Sumerian knowledge base (like Base-6 mathematics, irrigation systems/water management engineering and mud-brick cities). Traders often organized trading ports in distant places to easily find both markets with goods accumulated and a safe place to resupply/refit their ships (similarly to the Vikings' development of Dublin and Moscow, the Conquistadors in the Americas, Portuguese Macao, Dutch New Amsterdam, British Hong Kong, Spanish Manila). An interesting theory on the fish appearance would be some sort of chain mail or sewn discs (wood, metal, bone, seashell?) worn as armor in most cultures.>>
------------------------------------------------
http://members.shaw.ca/mjfinley/vondaniken.html wrote:
Image

"Palenque is a place in Mexico, and there is a large stone in the temple and
on the stone is a kind of being sitting like in a rocket." -- Erich Von Daniken

Image

<<Von Daniken's 1968 best seller, Chariots of the Gods, claimed that ancient civilizations from Mexico to China were visited by a space-faring race. His Maya astronaut was presented as a critical piece of evidence, the smoking gun that proved his theories: Here, he claimed, was a graphic image of an ancient astronaut, looking very like John Glenn lying in the Mercury capsule that took him into orbit in 1962.

Of course, on closer inspection, the resemblance isn't nearly as convincing as Von Daniken suggested. And we might have expected extraterrestrials who traveled light years to reach our planet to have space ships somewhat more advanced than 1960's earth technology.

But the biggest problem with Von Daniken's fantasy (apart from the sheer implausibility of it all) is that his "astronaut" is one of the most-studied of Maya sculptures. It is no spaceman at all, but a Palenque ruler named Pakal. Von Daniken's "large stone in the temple" is the lid of Pakal's sarcophagus. On it, Pakal is depicted on a cosmic journey, but he is not traveling in a space capsule. The inscriptions on the tomb tells us that Pakal has "entered the road": He has died and is falling along the axis of the World Tree into the Underworld. Glyphs about the sides of the tomb name his ancestors, other rulers of Palenque, who he is going to join. The World Tree is the most common Mesoamerican symbol of the creation and ordering of the "Earth-sky". At its foot (which Von Daniken took to be the rockets) is the face of the Maya water monster, a symbol of the entrance to the Underworld. Atop the World Tree is a celestial bird, representing the northern pole of the heavens.>>
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Re: Mayan water monster Oannes

Post by bystander » Fri Jun 19, 2009 5:52 pm

neufer wrote:Sumer was, in turn, preceded by the Mayan water monster Oannes: :wink:
Was Oannes a Sea Monster?

The Mayans also obviously knew about Planet X, the Sumerian Nibiru. Why else does the calendar end on December 21, 2012? :? :wink:

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Re: Mayan water monster Oannes

Post by neufer » Fri Jun 19, 2009 6:46 pm

bystander wrote:
neufer wrote:Sumer was, in turn, preceded by the Mayan water monster Oannes: :wink:
Was Oannes a Sea Monster?

The Mayans also obviously knew about Planet X, the Sumerian Nibiru.
Why else does the calendar end on December 21, 2012? :? :wink:
So the Oannes probandi is on us? :shock:
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Re: Old Dunhuang Star Atlas (2009 June 19)

Post by DavidLeodis » Sat Jun 20, 2009 11:40 am

What a fascinating star map. I was quite chuffed that I readily recognised some asterisms. :D

Just one point though. In the explanation it states "a very recognizable Big Dipper, part of the modern constellation Ursa Major, lies along the bottom of the chart". Is not the Big Dipper (the Plough to me) the asterism on the left of the image, not on the bottom :?: I suspect the image may have been rotated but the explanation was based on how the image was seen before rotation, unless that on the left is not the Big Dipper!

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Re: Old Dunhuang Star Atlas (2009 June 19)

Post by neufer » Sat Jun 20, 2009 1:37 pm

DavidLeodis wrote:What a fascinating star map. I was quite chuffed that I readily recognised some asterisms. :D

Just one point though. In the explanation it states "a very recognizable Big Dipper, part of the modern constellation Ursa Major, lies along the bottom of the chart". Is not the Big Dipper (the Plough to me) the asterism on the left of the image, not on the bottom :?: I suspect the image may have been rotated but the explanation was based on how the image was seen before rotation, unless that on the left is not the Big Dipper!
Most of the stars on the left side seem to be a dismembered Draco.

Below the long tale of Draco is the small triangular asterism of the raised "leash" hand of Boötes.

And to the right of that is the Big Dipper:
Image
Vincent van Gogh's Starry Night Over the Rhone, painted in September 1888 at Arles, depicts the Rhône River at night.
Last edited by neufer on Sat Jun 20, 2009 2:20 pm, edited 1 time in total.
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Re: Old Dunhuang Star Atlas (2009 June 19)

Post by DavidLeodis » Sat Jun 20, 2009 2:16 pm

Thanks neufer.

I now see the seven stars making the Big Dipper (the Plough), with a line connecting them, running along above other asterisms to the bottom. My asterisms identification is clearly rubbish, as I thought the Big Dipper was that to the far left of the map. :oops:

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Re: Old Dunhuang Star Atlas (2009 June 19)

Post by Case » Mon Jun 22, 2009 12:11 am

neufer wrote:Vincent van Gogh's Starry Night Over the Rhone, painted in September 1888 at Arles, depicts the Rhône River at night.
This painting is a view to the south, where Vincent took the liberty to place the Big Dipper there in the sky, where he could never have seen it like that, as Ursa Major is roughly towards the north. :D

Note that a painter (that cared more for colors and impressions) got the Big Dipper more accurate than the Chinese makers of the atlas, in that the stars Alkaid (η) - Mizar (ζ) - Alioth (ε) - Megrez (δ) form an arc instead of a straight line.
I, for one, like Roman numerals.

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Re: Old Dunhuang Star Atlas (2009 June 19)

Post by neufer » Mon Jun 22, 2009 2:24 am

Case wrote:Note that a painter (that cared more for colors and impressions) got the Big Dipper more accurate than the Chinese makers of the atlas,
in that the stars Alkaid (η) - Mizar (ζ) - Alioth (ε) - Megrez (δ) form an arc instead of a straight line.
But the handle used to be more of a straight line :!:
(And the bowl used to be more closed.)
http://en.wikipedia.org/wiki/Big_Dipper wrote:
<<Five of the stars of the Big Dipper are at the core of the Ursa Major Moving Group. The two at the ends, Dubhe and Alkaid, are not part of the swarm, and are moving in the opposite direction. Relative to the central five, they are moving down and to the right in the map.

This will slowly change the Dipper's shape, with the bowl opening up
and the handle becoming more bent.


In 50,000 years the Dipper will no longer exist as we know it, but be re-formed into a new Dipper facing the opposite way.
The stars Alkaid to Phecda will then constitute the bowl, while Phecda, Merak, and Dubhe will be the handle.>>
------------------------------------
http://en.wikipedia.org/wiki/Alkaid wrote:
Eta Ursae Majoris (η UMa / η Ursae Majoris) is a star in the constellation Ursa Major. It has the traditional names Alkaid (or Elkeid) and Benetnash (Benetnasch). The name Alkaid derives from "The leader of the daughters of the bier". The daughters of the bier; i.e., the mourning maidens, are the three stars of the handle of the Big Dipper, Alkaid, Mizar (star), and Alioth. It is known as 搖光 (the Star of Twinkling Brilliance) in Chinese.

Alkaid is the most eastern (leftmost) star in the Big Dipper (Plough) asterism. It has apparent magnitude +1.9, making it the 35th brightest star in the sky. It is a young bluish-white main sequence star of spectral class B3 V. At 20,000 kelvins it is one of the hotter stars visible with the naked eye.
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Re: Old Dunhuang Star Atlas (2009 June 19)

Post by neufer » Mon Jun 22, 2009 2:48 am

Case wrote:
neufer wrote:Vincent van Gogh's Starry Night Over the Rhone, painted in September 1888 at Arles, depicts the Rhône River at night.
This painting is a view to the south, where Vincent took the liberty to place the Big Dipper there in the sky, where he could never have seen it like that, as Ursa Major is roughly towards the north.
The painting is a view to the WSW, where Vincent took the liberty to replace the rather bland & obscure
constellation of Ophiuchus with the Big Dipper (which was roughly 90º to VIncent's right towards the NNW).
http://en.wikipedia.org/wiki/Starry_Night_Over_the_Rhone wrote:
The view is from the quay (a waterside street) on the east side of the Rhone, into the knee of the river towards the western shore: coming down from the north, the Rhone turns to the right at this point to surround the rocks on which Arles is built. From the towers of Saint-Julien and Saint-Trophime at the left, the spectator follows the east bank up to the iron bridge connecting Arles to the suburb of Trinquetaille on the right, western bank. This implies a view from Place Lamartine towards the south-west.

A similar view of the site, 2008
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Re: Old Dunhuang Star Atlas (2009 June 19)

Post by Case » Mon Jun 22, 2009 3:20 am

neufer wrote:But the handle used to be more of a straight line!
Okay. But how do you determine if it was a straight line only 1350 years ago?
I, for one, like Roman numerals.

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Re: Old Dunhuang Star Atlas (2009 June 19)

Post by neufer » Mon Jun 22, 2009 4:28 am

Case wrote:
neufer wrote:But the handle used to be more of a straight line!
Okay. But how do you determine if it was a straight line only 1350 years ago?
It wasn't a straight line 1350 years ago; but it was a little straighter.
(Perhaps it is a copy of a much older [4000 year old?] star map.)

http://apod.nasa.gov/apod/ap090619.html
Image
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Re: Old Dunhuang Star Atlas (2009 June 19)

Post by bystander » Mon Jun 22, 2009 7:17 pm

Case wrote:
neufer wrote:But the handle used to be more of a straight line!
Okay. But how do you determine if it was a straight line only 1350 years ago?
You could try Your Sky or some other star mapping site. I don't know how well any of them take into account the proper motion of the stars.

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Re: Old Dunhuang Star Atlas (2009 June 19)

Post by neufer » Mon Jun 22, 2009 8:22 pm

bystander wrote:
Case wrote:
neufer wrote:But the handle used to be more of a straight line!
Okay. But how do you determine if it was a straight line only 1350 years ago?
You could try Your Sky or some other star mapping site. I don't know how well any of them take into account the proper motion of the stars.
Here's an animation of the the proper motions of the Big Dipper:
http://www.youtube.com/watch?v=gJuAm0Q_fXE

Image
Art Neuendorffer

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Re: Old Dunhuang Star Atlas (2009 June 19)

Post by Case » Tue Jun 23, 2009 5:09 am

neufer wrote:Image
The arc in the line of stars is very noticeable here for the last ~20,000 years!
I, for one, like Roman numerals.

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Re: Old Dunhuang Star Atlas (2009 June 19)

Post by emc » Thu Jun 25, 2009 12:21 pm

cool anim of the BD Mr. Neufer!

As a child, I used to look up at the stars and thrill at recognizing the big and little dippers. I thought in simple X Y terms… and the stars were not moving. Now that I am all grown up (almost) I am learning to come to grips with the Z aspect of the heavens. And in addition, learning to cope with the perpetual and at times, disturbing movement of EVERYTHING. Nothing is the only thing not in motion of some sort in our universe, right? So point being, from the motions of the big dipper stars, the BD would not be a big dipper except for our meager (but ever-changing) vantage point.
Ed
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Sometimes the best path is a new one.

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