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yajvan
06 July 2010, 06:20 PM
hariḥ oṁ
~~~~~~~~
namasté

When astronomers look skyward they recognize ~ 88 constellations in the celestial sphere. In the astrology of the east ( jyotish) and the west 12 constellations are used. But why so?
The most obvious answer, 'these are the 12 constellations that the sun passes through and we call it the ecliptic part of the zodiac (kala-puruṣa).'

Let me ask you to take out any sky map and take a look at the signs ( rāśi¹) - trace with your finger across the ecliptic... nothing unusual.
But wait what is this? Between Scorpio (vṛścika - scorpion ) and Sagittarius (dhanu - a bow i.e. archer) there is the constellation called ophiuchus¹ or snake-holder ( some call it serpentarius ). If we consider ophiuchus that is in the path of the ecliptic we have 13 rāśi-s. Yet in jyotish we only consider 12 and smoothly transit from vṛścika to dhanu with ease.

Any ideas why we stay with 12 rāśi-s?

praṇām

words

rāśi राशि- is a heap, a mass, a pile, a group; in joytiṣ it is the name given to sign, as a collection point.
ophiuchus (OFF-ee-YOO-kus) http://www.iau.org/static/public/constellations/gif/OPH.gif (http://www.iau.org/static/public/constellations/gif/OPH.gif)

NayaSurya
06 July 2010, 06:59 PM
I will try to answer you.

The number may come from the same place that the houses comes from? We work with the visible area around us at birth. 360 degree/30 degrees (30 for the 3, 10 degree decanates) =12

NayaSurya
06 July 2010, 07:06 PM
Also could have to do with the fact that in a 24 hour day those 12 signs each take 2hr turns at rising?

yajvan
06 July 2010, 07:42 PM
hariḥ oṁ
~~~~~~~~
namasté nayasurya


I will try to answer you.
The number may come from the same place that the houses comes from? We work with the visible area around us at birth. 360 degree/30 degrees (30 for the 3, 10 degree decanates) =12

This is an excellent start. This 360º has much to do with it... now add in some thinking on the moon, from full moon to full moon and the timing, this will help.

praṇām

NayaSurya
07 July 2010, 11:22 AM
Sorry it took so long to come back. We just came home from vacation and my laundry room is in a catastrophic condition from all the wet clothing.:P

Now, you said that the 360 has something to do with this and to look to the full moon cycle to find out more?

It made me think of the Thidhis...and how each lunar day is delineated.

There are about 27 days to the cycle/30 sections, 360 deg/30= 12 degrees which is how far the moon races ahead of the sun at the end of each lunar day.

Which means a lunar day ends when the moon is 12 degrees ahead of the sun.

There are about 12 of these cycles throughout the year.

Does this have something to do with it?

yajvan
07 July 2010, 02:21 PM
hariḥ oṁ
~~~~~~~~
namasté nayasurya

Here's some more data that will help you think it through...

the moon's synodic month - 'the way of the sun' = 29.53 days ( nice and close to 30 days if we round up , yes?) - this is is the moon's rotation with respect to surya.

After the moon completes its sidereal month (27.3 days) it still has to go a bit further to reach the a new position i.e. a full rotation with respect to the Sun. Why ? because we, earth, are not standing still waiting for the moon, so the moon must travel a bit more to fulfill at full 360º around the earth, hence 29.53 days.

So in ~ 30 days ~ the moon completes this trip of 360º around the earth , with respect to the sun 360º/ 30º = 12 signs. The sun in ~ 30 days goes through a rāśi and the same number comes up = 360º/30º = 12 signs.

That is why using degrees ( vs. days) in jyotish to define a year is preferable to me i.e. defining the year as 360º .

So, the calculations for the number of signs are anchored in the movement of the luminaries - Sun & Moon and what a complete trip of 360º is for the sun ( a year) and for the moon , the synodic month.

Yet some things will change in the future ( millions of years) - why so? The earth is slowing down in rotation on its axis, the 'day' ; and the moon is moving farther away ( about 1.5 inches per year).

But what will not change is 360º travel , until we are swallowed up by the sun in ~ 4 billion years ( so say the astronomers).

Note - the discussion of tithi's are now something different and the moon becomes the center of attention. 27 nakṣatra's X 4 pāda's= 108 ~stops~, yet still there are 15 + 15 tithi's and back to 30.

praṇām

NayaSurya
07 July 2010, 02:40 PM
This conversation is one I must have my husband read. He is very very smart and studies much about astronomy. So when I posed your question to him...he began thinking of it in days.

I try to explain the 360 degrees versus days situation and he became very unsure what I was saying.

I told him that it may take 360 or 365...or someday 367 days to go around...but always...always our birth involves 360 degrees of the sky above us. This is a constant.

When we are born...in that second...a snap shot was taken. This does not change nor deviate from whatever method you use to think about it.

He is still clinging to the rotation and day count.

Thank you for explaining this more. I like to learn<3

yajvan
07 July 2010, 03:58 PM
hariḥ oṁ
~~~~~~~~
namast&#233; nayasurya



He is still clinging to the rotation and day count.

Thank you for explaining this more. I like to learn<3

Some info for your husband to consider....
http://novan.com/earth.htm

About 900 million years ago a 'day' was ~ 18 hours long&#185;. We are at about 24 hrs. today and slowing by a small amount each century. Yet in a billion years things change.

In 24 hrs. 30&#186; or 1 sign passes in 2 hrs. ( 15&#186; per hr.) If we had an 18 hr. day 20&#186; passes per hour or 1.5 hrs. for a 30&#186; sign.

So, things change, that is a constant.

praṇām

1. Bill Cooke, NASA

yajvan
12 July 2010, 08:23 PM
hariḥ oṁ
~~~~~~~~
namast&#233;



About 900 million years ago a 'day' was ~ 18 hours long&#185;. We are at about 24 hrs. today and slowing by a small amount each century. Yet in a billion years things change.
If a full day was 18 hrs. long how many days did it take to complete a year or 360&#186; ?

Today in one day ( 24 hrs.) we travel about 0&#186;59'10.68'' around the sun. If the full day was 18 hrs. long that is = to 75&#37; of today's 24 hr day ( 18/24 = .75). So in that 18 hr. period the earth would have travelled .75 X 0&#186; 59' 10.68'' which = 0&#186; 44' 23.0". That indicates 486.6 days per year,( 360&#186; divided by 0&#186; 44' 23.0"= 486.6 days).


Now one would perhaps say maybe with an 18 day as the earth is spinning faster on its axis it may slow down its angular speed around the sun.
I think not ( but look to the physics experts on HDF) because 98% of all the angular momentum in our solar system is provided by the sun. Our relative speed around the sun is not impacted by our own axial rotational speed. The dance between the earth and the moon is what affects the earths axial rotation as I recall.

What does an 18 hr. day suggest? Shorter days and nights. A full sign of 30&#186; would only take the sun 1.5 hrs to traverse.

What does a 488.6 days/year suggest?

praṇām

1. Bill Cooke, NASA

yajvan
15 July 2010, 06:24 PM
hariḥ oṁ
~~~~~~~~
namast&#233;



Yet some things will change in the future ( millions of years) - why so? The earth is slowing down in rotation on its axis, the 'day' ; and the moon is moving farther away ( about 1.5 inches per year).


Here is some speculation on my part...I have not been instructed on this matter&#185; , suggesting any blemishes are fully mine.

The moon today is 238.8 thousand miles from earth&#185; ( 384.5 km).
In 1 million years it will be 239.1 thousand miles from earth ( 384.92 km). As the moon moves away from the earth the center of mass also moves.
Today the center of mass (COM) is ~ 1 thousand miles below the earth's surface ( 1700 km). In 1 million years it will be 700 miles from the surface ( 1250 km).

As the millions of years pass the COM moves to the surface of the earth and then beyond the earth. So in 1 billion years it will be 22 thousand miles away from the earth's surface in space.
My conjecture is the following:

What does the moon represent and control ? manas.
Manas is considered :

intellect , intelligence , understanding , perception , sense , conscience ;
thought , imagination , invention , reflection , opinion , intention , inclination , affection , desire , mood , temper , spirit
the faculty or instrument through which thoughts enter or by which objects of sense affect the soul
manaḥ - to make up one's mind
Moon also suggests motherSo as COM moves outward, one's intentions become less self-centered. That is, less attention is on the wants and needs of the body but are pulled away to the higher qualities of SELF.
The 'center' goes from self (body) to SELF (spirit) . COM takes the individual from being earth centered (pṛithvī) to jala ( water) etc. to finally ākaśa (space) centered.

For me this suggests the march of the yuga from kali to kṛta (or satya) yuga and the blossoming of the human spirit as a society to the fullness of Being , the natural way of life.

praṇām

references


This goes under a conversation we had years ago on HDF as an original thought : http://www.hindudharmaforums.com/showthread.php?t=2772&highlight=original

Bill Cooke, NASA - Marshall Space Center

Mana
19 January 2012, 12:41 PM
Namaste yajvan, all,

Whilst pondering this question in the past; it has occurred that I wonder if the 12 year length of the orbit of Guru (Jupiter) about Surya (Sun), has effected the development of the 12 Rasi.

The presence of Guru in the night sky with his golden hues, quite clear to the keen eye; he dances across our sky marking out 12 zones by his retrograde effect, this being due to the ratio of 12 earth year to 1 Guru year or orbit, creating the impression of his dance as it also marks 12 apparent zones in our sky before arriving again at his point of origin 360&#176; later.

Just a thought, and a pleasure to read this inspirational thread.


praNAma

mana