05-28-2007, 05:28 AM
http://www.vedicastronomy.net/stars_appendix.htm
<img src='http://www.vedicastronomy.net/stars_images/Image13.gif' border='0' alt='user posted image' />
Astronomical time marks in Atharva Samhita & Jyotishya shaastra.
When was Atharvana Samhita composed?
Though we consider that the Star system to be basically stationary with reference to Solar system, there is an earth wobble occurring at rate of 26000 years per revolution which makes the star system appear to move slowly with reference to Sun. This has been called Earth's Precession and was first identified nearly 2000 years ago by Ptolemy and Hipparchus.
The position of Chitra (Spica), which is very near the ecliptic, was recorded by Hipparchus (circa 150 BC) on the autumnal Equinox day with reference to Sun. It was studied again by Ptolemy (circa 150 AD) nearly 300 years later on same autumnal Equinox day. Ptolemy found that Chitra appeared to have moved about 3 degrees toward Sun (Ref 4). Ptolemy decided that Sun was moving one degree for 100 years in reference to stars. This observation made nearly 2000 years ago, was probably the first documented recording of Earth's Precession. Today we know that Ptolemy was correct and that Earth's Precession rate is about 1.36 degrees for 100 years.
This 2000-year old observation, confirms the uniformity of Earth's Precession validating the geocentric mathematical models that exist for motion of objects in the sky. It allows us to extrapolate backward and forward in time, positions of objects in sky using computer software like Load Star pro. Thus, any past Sun position records, on Equinox/Solstice days referring Sun position to stars, carries the astronomical time mark of the period (Ref-8).
There are two possible definitions of a year as observed from Earth.
A Sidereal year is time taken for Sun to move from one star, and then come back to same star. This is full 360 degrees movement of Earth around the Sun.
A Solar year is the time taken by Sun in its passage from one equinoctical point back to same point.
One would expect these two years to be same, but Solar year is shorter than Sidereal year by about 19 minutes and 50 seconds and is said to be caused by inertial effects. It is called Earth's Precession.
First let us get a contemporary picture of the location of our solar system in the Milkiway galaxy. This is illustrated in figure below. Our solar system is located at the edge of the Milkiway disk of stars. The Milkiway is estimated to be about 50000 light years in its diameter. It consists of a large number of stars and other matter. The stars visible to our naked eye are generally within a few hundred light years around us. Some giant stars are located nearly 1000 light years are also visible to naked eye. Thus most of the 10000 stars visible to us are very near our solar system.
In the illustration below, the center of Milkiway Galaxy is in the direction of Moola nakshatra. Thus bulk of the Milkiway matter is concentrated, as seen from earth, near stars Jyeshtha, Moola, Poorva/Uttarashadha.
Because of Earth's Precession, the angle of earth's motion to come back exactly to same latitude (Solar year) is only 359.864 degrees around the sun. Solar year is the classical definition of a year, as the 23.5 degrees earth's tilt controls the weather, seasons and the position of Sun in its north-south traverse. A notional 360 degrees Sidereal year is irrelevant to us.
But the 359.864 degrees Solar year is relevant because of repeating weather and seasons and hence Solar year is a natural year. That means every solar year, the Sun position drops back by about 0.0136 degrees with respect to stars. Also, it may be noted that the earthâs spin polar axis also shifts by same angle of 0.0136 degrees per year in a coning motion. Most popular books on Stars illustrate this spinning top like coning motion property of Earth's Precession, but do not illustrate the apparent ecliptic plane motion of stars. The diagram below illustrates the star shift in the ecliptic due to Precession on spring equinox day. The diagram shows the 27 nakshatra's in a circle of diameter of the order of few hundred light years with sun at the center.
The diagram below shows the effect of Earth's Precession on Sun/Star/Earth's position exactly at the time of Spring Equinox. In this diagram, the Sun is always on equator and the day time equals night. Diagram shows Earth's position from 2400 BC to 2000 AD. Every year, the Earth's seasons start occurring 0.0136 degrees (or roughly 0.0136 days) earlier. The diagram also shows twenty-seven Bharateeya nakshatra's in the infinite distance in the ecliptic plane. It should be noted that the Precession does not change the Equator position or the Earth's tilt of 23.5 degrees. It only changes the direction of polar axis.
The Bhaarateeya Veda's have left some astronomical time marks in the texts. Amongst the Veda's, Atharvana Veda is considered to be chronologically the last. Based on the identification of the twenty-seven Baharateeya Nakshatra's, and using the astronomical time markers in Atharvana veda's 19th kaanda/ 7th sooktha. it is possible to to identify when the last of the veda's, Atharvana Veda was composed. The Atharva veda 19th kaanda/7th Sooktha reads,
<img src='http://www.vedicastronomy.net/stars_images/Image13.gif' border='0' alt='user posted image' />
Astronomical time marks in Atharva Samhita & Jyotishya shaastra.
When was Atharvana Samhita composed?
Though we consider that the Star system to be basically stationary with reference to Solar system, there is an earth wobble occurring at rate of 26000 years per revolution which makes the star system appear to move slowly with reference to Sun. This has been called Earth's Precession and was first identified nearly 2000 years ago by Ptolemy and Hipparchus.
The position of Chitra (Spica), which is very near the ecliptic, was recorded by Hipparchus (circa 150 BC) on the autumnal Equinox day with reference to Sun. It was studied again by Ptolemy (circa 150 AD) nearly 300 years later on same autumnal Equinox day. Ptolemy found that Chitra appeared to have moved about 3 degrees toward Sun (Ref 4). Ptolemy decided that Sun was moving one degree for 100 years in reference to stars. This observation made nearly 2000 years ago, was probably the first documented recording of Earth's Precession. Today we know that Ptolemy was correct and that Earth's Precession rate is about 1.36 degrees for 100 years.
This 2000-year old observation, confirms the uniformity of Earth's Precession validating the geocentric mathematical models that exist for motion of objects in the sky. It allows us to extrapolate backward and forward in time, positions of objects in sky using computer software like Load Star pro. Thus, any past Sun position records, on Equinox/Solstice days referring Sun position to stars, carries the astronomical time mark of the period (Ref-8).
There are two possible definitions of a year as observed from Earth.
A Sidereal year is time taken for Sun to move from one star, and then come back to same star. This is full 360 degrees movement of Earth around the Sun.
A Solar year is the time taken by Sun in its passage from one equinoctical point back to same point.
One would expect these two years to be same, but Solar year is shorter than Sidereal year by about 19 minutes and 50 seconds and is said to be caused by inertial effects. It is called Earth's Precession.
First let us get a contemporary picture of the location of our solar system in the Milkiway galaxy. This is illustrated in figure below. Our solar system is located at the edge of the Milkiway disk of stars. The Milkiway is estimated to be about 50000 light years in its diameter. It consists of a large number of stars and other matter. The stars visible to our naked eye are generally within a few hundred light years around us. Some giant stars are located nearly 1000 light years are also visible to naked eye. Thus most of the 10000 stars visible to us are very near our solar system.
In the illustration below, the center of Milkiway Galaxy is in the direction of Moola nakshatra. Thus bulk of the Milkiway matter is concentrated, as seen from earth, near stars Jyeshtha, Moola, Poorva/Uttarashadha.
Because of Earth's Precession, the angle of earth's motion to come back exactly to same latitude (Solar year) is only 359.864 degrees around the sun. Solar year is the classical definition of a year, as the 23.5 degrees earth's tilt controls the weather, seasons and the position of Sun in its north-south traverse. A notional 360 degrees Sidereal year is irrelevant to us.
But the 359.864 degrees Solar year is relevant because of repeating weather and seasons and hence Solar year is a natural year. That means every solar year, the Sun position drops back by about 0.0136 degrees with respect to stars. Also, it may be noted that the earthâs spin polar axis also shifts by same angle of 0.0136 degrees per year in a coning motion. Most popular books on Stars illustrate this spinning top like coning motion property of Earth's Precession, but do not illustrate the apparent ecliptic plane motion of stars. The diagram below illustrates the star shift in the ecliptic due to Precession on spring equinox day. The diagram shows the 27 nakshatra's in a circle of diameter of the order of few hundred light years with sun at the center.
The diagram below shows the effect of Earth's Precession on Sun/Star/Earth's position exactly at the time of Spring Equinox. In this diagram, the Sun is always on equator and the day time equals night. Diagram shows Earth's position from 2400 BC to 2000 AD. Every year, the Earth's seasons start occurring 0.0136 degrees (or roughly 0.0136 days) earlier. The diagram also shows twenty-seven Bharateeya nakshatra's in the infinite distance in the ecliptic plane. It should be noted that the Precession does not change the Equator position or the Earth's tilt of 23.5 degrees. It only changes the direction of polar axis.
The Bhaarateeya Veda's have left some astronomical time marks in the texts. Amongst the Veda's, Atharvana Veda is considered to be chronologically the last. Based on the identification of the twenty-seven Baharateeya Nakshatra's, and using the astronomical time markers in Atharvana veda's 19th kaanda/ 7th sooktha. it is possible to to identify when the last of the veda's, Atharvana Veda was composed. The Atharva veda 19th kaanda/7th Sooktha reads,