About Ophiuchus the 13th sign

Minderwiz

ravenest said:
I'd also like to thank the patient moderator

ravenest said:
No they don’t - as they assume the same point there is no need for the axis to change or become perpendicular because the sun ‘passes through that point’ (I think your usage of the term ‘ lie' on the equator is a bit confusing, the sun crosses the equator at that point)

ravenest said:
It’s fairly basic geometry and one needs to understand this before one can even contemplate celestial mechanics – however I do believe you have a good knowledge of astrological mechanics.

The moderator sighs, summons the patience of Job and counts to 10,000 then sighs again.

Ravenest,

I think we have a real communication issue here. So I’ll try and reiterate.

Looking at it from a Geocentric point of view (and I make no apology for that)

The declination of the Sun appears to change throughout the year, moving in a cycle from maximum 23.5 degrees North to maximum 23’5 degrees South. in respect of the equator. Now from a heliocentric point of view, this reflects the constant angle of the axis of Earth in respect of the ecliptic, if you take a heliocentric view. The change in declination in relation to the equator can be meaured through observation on Earth.

However my point was a geocentric one and I will continue it. as the Sun appears to move around the Earth, it’s declination must change from North to South and vice versa. The change over points, are on the equatorial plane (extended out into space) and for a moment, as the Sun touches this plane, Earth’s poles are perpendicular to it.

From a Geocentric point of view the Sun’s declination varies, From a heliocentric point of view the Earth’s axis maintains a constant angle to the ecliptic.

The change of seasons from a Geocentric point of view is due to the changing declination. From a heliocentric point of view it is due to a change in the angle of incidence between the Earth and the Sun’s rays due to the tilt in the Earth's axis. At the Equinoxes the angle of incidence is 90 degrees and the circle of illumination passes through the poles. The poles are perpendicular to the Sun’s rays.

Now I don’t expect you to take my word for this last point. Please read

http://daphne.palomar.edu/jthorngren/tutorial.htm

You will even find a diagram showing this.

So No, I’m not claiming that the Earth’s axis changes. What I am claiming is that at the equinox the Sun is in the same plane as the equator and is at right angles to the poles (Geocentric) or that at the Equinox the Sun’s rays are at right angles to the Poles (Heliocentric).

At all other times the Sun has declination North or South (Geocentric) or the angle of incidence of the Sun's rays varies from 90 degrees to a greater or lesser extent (Heliocentric)

Edited to add:

I am not citing the above to try and prove you 'wrong'' merely to stress the difference in reference points used by us. The communication issue relates to my post on the equinoxes giving a Geocentric explanation. As I had stated the geocentric concept in relation to the seasons earlier I assumed that in my post. Message 'Never assume anything'

ravenest

Thanks HEAPS Mindy!

I dont have time for anything but a quick read of your last post but I will take a copy home and examine this, we might (now) be actually saying the same thing (see below) as I try to struggle through the syrup of my mind (or perspective outlook).

ravenest

You sigh, I ... aarrrgggh!

I went through all this in my now twisted brain and believe I have an answer, wrote it out at 1am last night, downloaded to USB and this bl**dy internet station USB port dont work. I will try later at another place.

ravenest

Minderwiz said:
http://daphne.palomar.edu/jthorngren/tutorial.htm

You will even find a diagram showing this.

Ooohhhh, I'm gonna have fun withTHOSE diagrams

ravenest

Try a new computer

(Ah ... this is better)

I was thinking about this last night and decided I HAVE to be wrong in thinking you mean what I thought you did, because you cant mean that , that the axial tilt of the earth, goes from 23 deg, to perpendicular at an equinox. It’s too crazy and must be a different framework used in astrology or the terminology is wrong or something. So now my head is doing gymnastics trying to nut out another interpretation of what you guys mean.

I am thinking in terms of celestial mechanics and astronomy, BECAUSE of the dictionary definition - "celestial mechanics–noun-the branch of astronomy that deals with the application of the laws of dynamics and Newton's law of gravitation to the motions of heavenly bodies. "
And in astronomy; [Norton’s Star Atlas p.5]
“Fundamental concepts.
The Celestial Sphere.
A convenient means of studying the relative positions of heavenly bodies based upon their appearance to the observer … most problems in positional astronomy can therefore be solved by the use of SPHERICAL trigonometry … the hypothetical concept of a celestial SPHERE is INVALUIBLE as the foundation upon which all fundamental considerations of the positions and motions of heavenly bodies are based.”
[My emphasis – note; sphere means 3-D]

I was not thinking in terms of astrology as you Dave said I needed to understand celestial mechanics ... which I believe I do and the celestial sphere by the way IS a geocentric concept.

So now I am trying to figure it out from a variant point of view.

I think astrologers mean this: The line of the directional pointing of the earth’s axis is perpendicular to the sun at an equinox. Stripping down Dave’s triangle model the essentials I see are the directional pointing of the axis and the sun. If I draw this on a piece of paper I draw a vertical line (axis) and mid way along the line, off to the right I draw a dot (sun). I can see how the sun is ‘square’ to the line and I can draw a line from the sun to the middle of the line and see a perpendicular relationship.

I can understand that if I see it as a flat map the earth is square to the sun but usually the relationship of the earth’s axis to the ecliptic is thought of in an extra dimension, a 3-D model. So I take a piece of round paper, dot a circle in the sun for the middle, a smaller one out from the sun for the earth, the edge of the paper is the circle of the ecliptic. I pierce the paper with the pencil at the earth and pull it half way through and hold it straight out in relation to the surface of the paper and the ‘ecliptic edge’ of the paper to make it perpendicular to the ecliptic. This is what I thought you meant by perpendicular to the ecliptic. But this is wrong, and I must give you guys credit that you cant think that is what is happening.

So I tilt the angle of the pencil 23 degrees; this is a more correct model but the axis is not perpendicular ... Until, I hold the piece of paper up and look at it side on (another view of the object in 2-D but from another direction – sideways instead of looking down from the top as in the line and circle model) the axis is still 23 deg BUT as I slowly rotate the paper and hold it level the pencil moves around the circle and APPEARS to become perpendicular to the side view edge of the paper representing the ecliptic!

MY GOD- it’s the Uri Geller spoon bending trick! This must be what you mean also.

At present the only way I can see a perpendicular relationship between line and circle is to view the model sideways with the pencil sticking through the paper and rotate it until the pencil appears vertical BUT this is only possible due to angular relationships in the 2-D side on view.

I can see how both these dynamics occur at an equinox depending on ones viewpoint but I haven’t seen this in astronomy or referred to in a star atlas, or any definition of an equinox, equinoctial point, or ecliptic, none of the definitions of these things in my Norton’s (star atlas) mention it.

I can see the axis can appear perpendicular to the ecliptic in 2 different 2-D views (from the side and above) and not in 3-D, and this 3-D view, I believe is fairly essential in studying celestial mechanics (which is the level I assumed we were talking on as BOTH of you referred to the need to understand celestial mechanics to understand what you were talking about). Perhaps you meant astrological mechanics?

I find, although correct from limited viewpoints, 2-d maps very narrow and not as correct and they lead to misinterpretations, not an opion just held by me but also; "most problems in positional astronomy can therefore be solved by the use of SPHERICAL trigonometry … "

If the refrence to my lack of understanding of celestial mechanics is causing confusion one should understand that that celestial mechanics is part of astronomy and that best works with a 3-d GEOCENTRIC map using spherical trigonometry. While astrology seems to more utalise 2-D models from varient viewpoints.

Minderwiz

I don't make any claims for expertise in celestial mechanics, as my original post clearly states. So I say the next bit with some trepidation.

You seem to assume that I refer only to a 2-D model. Even in a 3-D Geocentric model the Sun is at right angles to the polar axis at the equinox. Simply extend the plane of the equator (NOT the ecliptic) into space (as said in my previous post) and at the point the Sun passes through this plane, from below to above and vice versa, it's centre will at some moment lie on this plane and it is as right angles to the poles. Not before, Not after, but at that point.

From a Geocentric point of view the Sun's angles to the polar axis and to the equator varies throughout the year. The axis remains constant. From a Geocentric point of view we can take the polar axis as vertical with the ecliptic inclined to it (Heliocentric the ecliptic is at right angles to the Sun's axis and the Earth's axis is inclined to the ecliptic).

Now all that I am doing here is suggesting that the Geocentric explanation of the seasons is actually a useful one for the basis of Tropical Astrology. Though Tropical Astrology is perfectly consistent with a Heliocentric View as well. to quote from the web page I cited:

'Midway between the solstices are two dates when the sun shines directly on the equator, and we have a situation like our hypothetical one, where the earth's axis is perpendicular to the ecliptic. (The axis is still tilted, still pointing at the North Star, but it is tilted sideways with respect to the sun, rather than towards or away from the sun). )The circle of illumination passes through the poles, the sun's rays strike the equator at an angle of 90 degrees'

Now it is the change is in tilt of individual poles, either towards the Sun or away from it that cause the seasons. Where the tilt is 'neutralised' at the equinoxes we get the Sun perpendicular to the poles both EFFECT and also in FACT - IF we shift our point of view.

And I think you put your finger on the change in viewpoint in an earlier post.

Try getting an Orange and sticking a knitting needle through it's centre. Take a Football and clamp the orange with the knitting needle square on to the football but at an angle, from your current viewpoint.

Now shift your viewpoint so that the knitting needle appears vertical (without moving the orange, or the football in any way) Look towards the football and you will see from that viewpoint the needle IS perpendicular to the football, i.e. the tilt is irrelevant. Point either the sharp end or the blunt end towards the football at an angle and the tilt becomes very relevant.

Shift the viewpoint from the ecliptic but leave the celestial bodies in their equinoctial positions and the Earth still tilted in relation to the ecliptic and you will find a viewpoint in which the poles are vertical, and perpendicular to the Sun. To misquote Einstein, perpendicularity is relative to the location of the observer.

Now I suspect we both agree on what I have said above. I also suspect that the confusion arises because I'm talking about points and you are talking about lines - which you seem to recognise in a previous post.

Bernice

Minderwiz explains it very well ravenest

A long time ago I got The Astrologers Astronomical Handbook by Jeff Mayo. This book also explains it very well, and includes small diagrams for clarification.

As Astrology is the 'Mother of Astronomy' it's worth coming at it from the astrological viewpoint.

Just a suggestion.

Bee

Minderwiz

Thanks Bernice. I try my best to be accurate but Celestial Mechanics is NOT my forte.

In case my explanation above is not absolutely clear as a 3-D model, have a look at this video on UTube

http://www.youtube.com/watch?v=taHTA7S_JGk&feature=related

This shows a shift in viewpoint that makes the polar axis perpendicular to the Sun's rays (and of course the Sun).

ravenest

Bernice said:
Minderwiz explains it very well ravenest

A long time ago I got The Astrologers Astronomical Handbook by Jeff Mayo. This book also explains it very well, and includes small diagrams for clarification.

As Astrology is the 'Mother of Astronomy' it's worth coming at it from the astrological viewpoint.

Just a suggestion.

Bee

Thanks B. I'm about to eat humble pie (with smart alec sauce).

ravenest

Doh!

Ermmmmmmm. I finally got it. What's wrong with my brain. ( I know, I know, your gonna say ":well that's a question you should ask a psychologist, not an astrologer." :laugh:

)

I wont go through my other questions ( re shift of equinoctal point as cultural marker) as Minderwitz probably needs a holiday - from me. Although I reckon I owe him a lobster dinner by now.

[I had a dream about him last night, he looked like his avatar and was my next door neighbour ... I looked Denis the Menace, he was Mr. Wilson. I better not say what happened in the dream - Poor Minderwiz! Oh dear, I should pay more attention to my unconcious.]

Sorry if my obsinate confusion confused anyone else. A friend explained it to me like this; when an axis goes 'straight through' a plane it is perpendicular to the plane in the 3 directions, in this case it is only perpendicular in 2 directions the other is 23 deg off. And then I finally saw it in my brain. If I stand a match straight up from a compass face and tilt it 23 deg to north the match is 90 degrees to the east and west. There is still something I am not getting about it when I rotate the different maps in my head, but I guess I will get that too eventually.