On Sat, 12 Mar 2011 09:49:24 -0000, "Androcles"
wrote:


"Henry Wilson DSc" Hw@.. wrote in message
.. .
| On Fri, 11 Mar 2011 22:15:32 -0000, "Androcles"
| wrote:

| | Even if the orbit were perfectly circular (which in most cases it is
not)
| | the function would give an initial velocity of c+v.sin(t/period modulo
| 2pi),
| | you need to convert t/period to a pure number for dimensional analysis
| | and then convert to radians to become the argument of the function
sin()
| | (or cos(), depending on your arbitrary choice of axes).
| |
| | t/T IS already a pure number. The 2pi turns it into a phase angle, in
| | radians....also a pure number...I usually leave out the 2pi because it
is
| | understood.
|
| What you call T is the period, P.
| When I wrote Doolin'sStar I used T for the APPARENT time interval.
| http://www.androcles01.pwp.blueyonder.co.uk/Doolin'sStar.GIF
| You are not helping by changing the definition of variables.
|
| Let's not argue about trivialities, chief. When you adjust your time axis
for
| arrival time of each sample 'bunch' your program will produce the same
curves
| that mine does.

Yes, but now that we agree on the principles involved it is time to step
back, look around and tidy up the mess left behind. That's what you are
writing about, so let's cross the 't's and dot the 'i's and leave a neat and
tidy theory without any loose ends.


| | So T must be the
| | period (symbol P) and t must lie between 0 and 2pi.
| |
| | We know the correct equation is c + v(cos(2pi.t/T), where v is the
radial
| | velocity. That means it already includes cos(pitch)
|
| *I* know that v is your sqrt(vellx^2 + velly^2), see sheet 2 of
| http://www.androcles01.pwp.blueyonde...lsonMethod.xls
| because Wilson's Wobbly Worbits are Wedge-on and v does not
| include cos(pitch).
|
| Cos pitch is included in my velocity value. that should be obvious.

Obvious to you but it isn't obvious to others. The orbital velocity isn't
even close to the radial velocity, yet you want to call both of them v.

You don't get it.

I first generate an ellipse, starting at the periastron. I plot 40000 points
around the orbit spaced equally in time. At each point, the peripheral velocity
and its angle relative to the direction of the minor axis are recorded in two
arrays. The maximum speed, at the periastron is assigned the value one and all
other speeds are expressed as a fraction. The same proportions hold for all
ellipses of the same eccentricity.
Yaw angle is that between the observer and the major axis. Adding that to the
peripheral angle and multiplying by the peripheral speed gives the radial
velocity for the edge on orbit.
My 'Pitch' is then defined as rotation around an axis perpendicular to the LOS.
Rotating the ellipse around that axis multiplues ALL the radial velocities by
the same factor, cos(pitch). So pitch can be omitted from the equation. It is
present in the velocity figure.

You know what you mean but nobody else does.

well they should try bit harder.

....but the same definitely applies to YOUR demos....they invariably have no
accompanying explanations and are meaningless.

Look, if I go into a shop in Britain to make a purchase, the price on
the sticker is the price I pay and it includes value added tax (VAT).
That should be obvious.
But if I go into a shop in the USA to make a purchase, the price on the
sticker does NOT include sales tax. I have to pay more than the sticker
price. That should be obvious.
Two different conventions are never "obvious".
The date today in Britain is 12/3/2011, obviously.
The date today in the USA is 3/12/2011, obviously.
No, it is not the 3rd of December yet, it is still the 12th of March.
The USA has a conventional way of writing the date: month first,
then day, then year. It's no good saying which is right and which
is wrong, it is their convention, and anyway both are wrong, it
should be year first as that is the most significant. But when in
Rome, do as the Romans do. What you are saying is NOT obvious.

very little of what YOU say or write has an 'obvious' meaning.


| Ok, so v isn't the radial velocity, it is the orbital velocity composed
| of vellx and velly, and P is the period, not T.
|
| The usual convention for period in for instance, the traveling wave
equation is
| the agreek letter Tor, which is replaced by T in ascii.

The greek letter is 'tau', not 'tor'.

It was TOR when I was taught. Tau is something else.

That is precisely the kind of ugly mess and confusion you are leaving
behind that I'm talking about. The relativists confuse t, tau and t' because
they are following their own convention and think it is obvious, but
Einstein has a clear distinction between x, x' and xi and does not use t'
at all. That's how the arguments begin.
We are talking here about the time to complete an orbit, and that means
there is a one-one mapping from t/P to angle. We are not discussing
a ****ing wave equation.

In physics, P stands for pressure. T for period.


| I have explained how all orbit configurations can be accomodated by using
edge
| on ones. I also expect my readers to be able to understand what my (few)
| equations imply.
|
It's ok to have few equations. Indeed, the fewer the better. It is not ok to
embed cos(psi) in v.sin(phi+t/P) and then assume it is "obvious". The time
has come to be clear and concise, you are now at the writing stage, and I
expect you to be able to understand common ****ing sense. Why is it
difficult for you to understand other people are not going to make your
assumptions?

Figure 1 shows and explains the principle quite clearly.

Britain: price includes VAT.
Round the price up, take off a penny, it's £4.99 inc VAT.
I get a penny change from a £5 note.
USA: price does NOT include sales tax.
Round the price up, take off a penny, it's $4.99 + tax = $5.34,
let the purchaser know how much his government is charging.
I need another few cents to pay for my chocolate and now I'm
embarrassed, I don't have enough change and didn't understand
the "obvious" convention.