On Sun, 25 Feb 2007 10:07:58 -0000, "George Dishman"
wrote:


"Henri Wilson" HW@.... wrote in message
.. .
On Sat, 24 Feb 2007 21:45:21 -0000, "George Dishman"
wrote:
"Henri Wilson" HW@.... wrote in message

No No No.
For BaTh, the width of the actual pulses DOES NOT change after emission.
The
spacing between them DOES.....because they are moving at different speed
wrt
the Bcentre.

Yes yes yes There are two problems with what you say:

First, the pulses from J1909-3744 are 45us long. Think of
opening the door on the front of an incinerator for a few
seconds then closing it, all this on a planet in orbit round
a star such that the planet is being accelerated towards a
distant observer. That observer sees the thermal radiation
from the fire appear, last a short time then vanish.
According to ballistic theory, the radiation emitted just
before the door closes travels faster than that emitted just
after it opened. The tail of the pulse therefore catches up
with the front so the length of the pulse shortens by exactly
the same ratio as the gap between the pulses.

Point taken ..

Excellent. We now seem to be in full agreement on this
issue. All that remains is for you to correct the program.

Well the program is correct as far as producing brightness curves.

What YOU are asking is that I predict the true velocity curve from the
willusory one we obtain on Earth. Then, since my brightness curves are based on
TRUE radial velocities and since my observed radial velocities are now to be
based on the brightness curve, I will have to step by step, change the various
parameters until I find the true radial velocity curve that results in my red
curve looking like my brightness curve.

I'm not sure this is possible.



.. but there are several problem with what YOU say.

Well let's see.

Firstly that is only true if speed is constant wrt the source.

That is the postulate of ballistic theory so it is not
something you can question. This is where other people's
comments apply, you cannot be selective about when you
use the postulate and assume a speed independent of the
source when the postulate gives an answer you don't
like.

In this orbiting
situation, an acceleration is present..

Yes, it is that acceleration that causes the catch-up effect
which (a) causes one pulse to catch up to the one ahead and
(b) causes the tail of a pulse to catch up to the head.

..and a VARYING one..

Yes, the greatest cach-up is when the pulsar has the highest
acceleration towards the observer. For a circular orbit that
is when the pulsar is directly behind the companion (superior
conjunction). That gives the high peak in the brightness
while half an orbit later it causes a reduction in brightness
as the pulses spread farther apart while travelling.

...meaning that
the two ratios are NOT the same.

No, the ratios are always the same but it means that ratio
varies for light emitted at different places round the orbit.

There is a second order accelertion effect that might be important.
For instance the velocity ratio is not the same across a 100 nanosec pulse as
it is across a 0.1 second pulse gap.

Secondly it is not terribly clear what actually causes Pulsar pulses.

That doesn't matter, the postulate of ballistic theory must
still be applied.

Not necessarily.

There is
some kind of interaction between the rotating magentic field and charged
material EXTERNAL to the neutron star itself. There is no certainty that
this
material is rotating at the same rate as the star...more likely it is
'fixed'..... otherwise we wouldn't see sharp pulses at all.
It might not even be rotating with the orbit of the pair.

If that was the case the pulses would not show any Doppler
at all. The whole pulsar system including the neutron star,
the fields, any jets and so on are being moved in an orbit
by the distant white dwarf and ballistic theory then tells
you what the pulse spacing will be.

Maybe...maybe not..

Second, and more important, nobody uses the width of the
pulse to calculate the Doppler, they use the pulse frequency.

I'm suggesting they should

Tough, they don't. Your red line should be a prediction of
what will be measured using the actual technique employed
by radio astronomers so that it can be compared with the
published curves.

And astronomers wrongly assume that the red curve is always identical to the
blue one....because Einstein said so...

....and according to you it should be the same...

According to the postulate of ballistic theory they must be
the same.

I think I would also suggest there would be a ~90 degree phase shift
between
velocity curves produced by the two methods.

Above you said "point taken". That point requires that they
have the same ratio at all times so no phase shift is
predicted by ballistic theory. You seem to be making a
handwaving claim which contradicts your own theory.

no...just jumping from one theory to another...

Whether the width changes or not is therefore of no relevance,
unless you use the gap times you won't get a curve that can be
compared to published curves or data derived from them such as
J1909-3744's published orbital parameters.

It might be very relevant. Without precise knowledge of the manner in
which the
pulses are generated, I would not claim for certain that what you say is
wrong
in the case of pulsars...... but this is not a problem for my program
because
the ENERGY in each hypothetical pulse remains the same whether or not its
width
varies as it travels....and the program sums the energy arriving per unit
time
to produce brightness curves.

I am not disputing your brightness curves. There are some
subtleties in energy calculations in ballistic theory but
they would have a very small effect. We may come across
them later.

Yes, I have thought of including KE ...but I think it's pretty negligible.

For the moment, there is a gross error in your red line
which needs to be corrected.

Well I might see what I can do. ..just to make you happy.

snip photons until the program is fixed for pulsars

So the spacing...or bunching... is not a direct indicator of doppler
shift
or
relative source velocity..
The PULSE WIDTH is.

Apologies to others for apparent shouting but I'll use caps
for emphasis as Henry has.

No Henry, with ballistic theory NOTHING about the signal is
indicative of the original velocity, but that doesn't matter
anyway because NOBODY PUBLISHES VELOCITY CURVES BASED ON THE
PULSE WIDTH.

Because it is obviously rather more difficult...and besides, they don't
want to
reveal the fact that the answers seem quite different when they DO try.

Nonsense, a lot of work goes into that but in most pulsars
there is a lot of variability in the pulse for other reasons.
Anyway, ballistic theory if correctly applied as above says
the two factors should be the same.

.....only according to the classical view.
My photons don't have ends that continue to move.


big snip - Henry the aspect of optical wavelengths is
more complex and will totally confuse the issue if we get
sidetracked so I'll leave it for another time. Let's
finish the discussion of pulsars and get your program
corrected.

The program does not need correcting.

Yes it does, you have agreed that above. The velocity curve
needs to be derived from the pulse spacing because that is
how astronomers measure the Doppler.

This will take some time...

It doesn't operate on pulse
width...rather, pulse energy....and that's near enough to being constant.

No, that's what you do for the brightness curve. You are
confusing the two. The brightness curve is valid, the
red velocity curve is not.

....we'll see. If we are both correct then ALL astronomy will be turned oinits
head.

It is correct the way it is.

No, you said above "point taken" and that means the program
is wrong as it stands.

It wasn't designed for pulsars, George.

However it is not set up for analysing pulsars
because there are no 'brightness curves' available.

You don't need a brightness curve, the velocity curve tells
you all you need to know which is why you need to correct
the red curve to make the program usable. If you want to
keep your existing inaccurate version, just take a copy and
correct that for the pulsars. That program will let you
analysed the extinction length based on the velocity curve
alone.

I'll just add another function.
It wont be that hard actually.

George


"When a true genius appears in the world, you may know
him by this sign, that the dunces are all in confederacy against him."
--Jonathan Swift.