"Henri Wilson" HW@.... wrote in message
...
On 15 Mar 2007 01:26:03 -0700, "George Dishman"
wrote:

On 14 Mar, 23:10, HW@....(Henri Wilson) wrote:
On 14 Mar 2007 01:26:51 -0700, "George Dishman"
wrote:
On 13 Mar, 23:35, HW@....(Henri Wilson) wrote:
On 13 Mar 2007 01:24:19 -0700, "George Dishman"
wrote:
On 12 Mar, 22:11, HW@....(Henri Wilson) wrote:

The phase difference between the blue and green curves appears to
remain the
same 90deg for distances of 0.2LYs and 200LYs.

Our previous estimate was about 6 light hours so
at 0.2 light years the acceleration dominates
completely.

Well I don't get any change of phase.

OK, I'll wait for you to fix that bug too.

...
Whatever it is, it still tells you the phase which
is all we are using it for.

George, there is an anomaly in the data when it is interpreted in the
conventional way. Shapiro delay appears to account for it.
I'm not prepared to accept that explanation.

Suit yourself, all I am asking you to accept is that
an elliptical orbit with its major axis aligned with
our line of sight is symmetrical about that axis. It
means the anomaly can't be on one side or the other.

You keep complaining that you don't have enough
information to analyse the system but at the same
time ignore an artefact that answers your question
whatever causes the effect. It is sad that you should
be looking for excuses for failure before you even
make the attempt.

It might be an option. We will see.
More important data would be a brightness curve of the dwarf.

Other factors enter into the
picture when the BaTh is used.

According to the BaTh, there will be a slowing of
light as it escapes the gravitational influence of the pair.

At some distance from the system there will be a
slowing which is close to the effect of a point
mass, the separation of the two bodies becomes
negligible. The Shapiro delay is how the slowing
varies relative to that mean effect as a function
of the phase.

I don't think it will make any significant difference to my brightness
curves
except maybe when a very heavy star is involved.

Absolutely none whatsoever, nor will it have any
significant effect on the velocity curve. It is a
very small delay of the signal only.

yep.

I already have a program that predicts redshift due to gravitational
slowing of
light. It can accommodate the slowing from a whole galaxy. The source
can be
positioned anywhere inside that galaxy.
I suppose I can modify this and include it in my variable star program.
It
could provide interesting results when heavy stars are involved.

Nope, that would be of no use at all. Consider a simple
circular orbit of the pulsar P around the barycentre B
as seen by an observer O very far away (not to scale):


B

P x P' O

| |
|- D -|

Light from the two locations P and P' would be launched
with the same speed towards the observer, c' = c+0.7v,
because I've drawn them at 45 degrees to the LoS. The
light from P would be expected to take D/c' longer to
reach us.

That's a strange drawing George.
The barycentre should be where x is.
Anyway I know what you mean.

I don't think you do. Let me add the location of the
companion dwarf as C and draw the two situations
separately. Here's the first:


C


B

P O


The companion is lighter so it's farther from B. Here
is the second situation quarter of an orbit later:


C


B

P O

Of course the observer sholud be farr off to the
right of your screen

P

B O

P'

Point x is midway between P and P' where the light path
is perpendicular to line x-B. In ballistic theory the
gravity of the star accelerates the light between P and
x and then slows it between x and P' so that the speed
at P' is the same as light emitted at P'. Everything
from there to O is the same. The time it takes the light
to get from P to P' is therefore slightly _less_ than
D/c' because the mean speed is slightly higher than c'.
The Shapiro effect is the difference between that time
and D/c'.

Yes I'm aware of this. The average speed is faster than c' between P and
P'.

Right so the signal arrives earlier, it is not a delay.
The gravitational redshift is identical in each case as
is the eventual speed.

....
That was before we fixed the bug in your program.
Now we have found another. Once we get through the
pulsar analysis and you have learnt how to get
definite answers out of the data, we can have a
look at RT Aur and see how good your match is, but
at the moment you don't seem to have the VDoppler
term in your program so your phase is screwed.

Well I have given it some more thought.

Consider a pulsar in an edge-on circular orbit.

Pulses from the near and far sections of the orbit move towards you at c
and
that from the edges at c+v and c-v.

Bunching of pulses is a maximum at maximum acceleration, ie., for pulses
emitted from the far section of the orbit. It is minimum for those emitted
at
the near, or 'convex' section.

However, the 'bunched section' moves towards the observer at a slower
speed
than does the group of pulses from the edges.
Now, my original method does not take this into account, although the red
velocity curve it generates actually shows the arrival velocities.

The velocities affect the 'y' position but the changed
time of arrival affects the 'x' position. However, any
change in that from one pulse to the next also affects
the _relative_ separation hance looks like a modification
to the velocity.

I cannot yet see how your 'pulses separation' method does NOT include the
VDoppler.

It SHOULD include it but if as you say above your program
does not take this into account, that could explain why it
is missing the VDoppler effect.

I think it might be where you decided to ignore the
orbit crossing time. That's not a problem but the
rate of change of the time gives the VDoppler so
you need to make sure that's accounted for.

What I will do today is write a new program showing how the pulses
actually
move wrt each other as they travel away from the source. I have already
done
this in my 'lightfronts' section but I will modify the presentation so
that it
shows the positions of about 300 pulses emitted around one orbit.

If that helps you understand how the effects combine, do
so but getting the VDoppler accurately into your prediction
is the aim, you won't get an accurate phase shift without it.

George