Why are the 'Fixed Stars' so FIXED?

On Sun, 18 Feb 2007 09:31:57 -0000, "George Dishman"
wrote:


"Henri Wilson" HW@.... wrote in message
.. .
On 16 Feb 2007 00:38:58 -0800, "George Dishman"
wrote:
On 15 Feb, 23:15, HW@....(Henri Wilson) wrote:
On 15 Feb 2007 05:33:24 -0800, "George Dishman"
wrote:
On 15 Feb, 12:48, bz wrote:
"George Dishman" wrote
oups.com:
On 14 Feb, 23:29, bz wrote:
HW@....(Henri Wilson) wrote

In that case which non-variable spectroscopic
binaries have you analysed and what wa the
predicted light curve?

George, like I said, the biggest problem for me is to find both velocity
and
brightness curves for the same star.

I asked about non-variable stars!

"bz" wrote in message
. 198.139...

The brightness curve looks like this:
----------------------------------------------------





Brightness curves for near circular orbits are pretty well the same so all
I
need is the magnitude change and maximum velocity.

If you can find some examples for me I will try to match them.

You could ask in sci.astro.research, all you need
is the velocity curve and a paper that says "No
brightness variation has been detected to the level
of *** mag."

There are plenty of reason why no brightness variation will be expected.

There appears to be another factor contributing to light speed
unification
other than plain space density of matter.
Maybe this is related to the gravity field of the stars involved. I have
no
explanation as yet.

Gravity would slightly couteract the speed unification
effect but it is a second order effect so increases the
unification distance by about one part in ten thousand
typically, completely irrelevant as you don't know the
distance to within an order of magnitude yet.

I'm not trying to explain it at this stage. I just want to find a
consistent
pattern. Unification distance appears to be definitely related to orbit
period.

That would suggest a non-linear relation between (v-c/n)
and dv/ds. It still needs to be first order at zero but
perhaps a third order component? Gravity certainly isn't
going to do anything for you.

I'm not so sure of that.



Well 'rapid' is subjective. What I mean is very
much less than the parallax distance to the system.

for small period orbits, yes...but not so much for orbits over about a
year.

Once the light leaves the star, the only remnant of that
is the difference between the actual speed and c/n.

However the brightness is predicted to go to
infinity at the critical distance when the first double image would
occur.
Since this doesn't seem to happen and multiple images are not commonly
observed, I am prepared to accept that exinction rates are normally
fairly
high.

That's all I meant. Typically it must be no more
than a fraction of a light year.

No. It doesn't work like that. Something makes it period dependent.

It can only be the speed.

....and maybe distance between 'pulses'. Similar really.

After all,
you cannot unify light with other light that hasn't yet been emitted.

Nothing of that kind was suggested. The pulsar is an
obvious example, each pulse is 45 us or 13.5 km long
and they start out 2.95 ms or 885 km apart. The highest
frequency shift is 30.54 mHz so over the entire journey,
the faster pulses only catch up by 79.7 m. You explained
this yourself in another post:

"Henri Wilson" HW@.... wrote in message
.. .

The light from these stars still travels throgh similar quality space,
even if
it emitted months later.

Eventually the pulses change speed (asymptotically as has
been said) to c/n but it is the 'quality of space' as you
nicely put it that is responsible, not another bunch of
photons 885 km away, and bear in mind too that the speed
doesn't just come to match adjacent pulses but _all_ the
pulses emitted over the 1.5 day orbit end up at exactly
the same speed.

There's plenty time for that to happen, you figure for
the critical distance is 8 light years and the system is
over 3000 light years away.

there is a lot to be done yet George.


George

On Sun, 18 Feb 2007 11:06:58 -0000, "George Dishman"
wrote:


"Henri Wilson" HW@.... wrote in message
.. .
On Fri, 16 Feb 2007 12:18:29 +0100, YBM wrote:

Henri Wilson a écrit :
On Thu, 15 Feb 2007 23:43:23 +0100, YBM wrote:

Henri Wilson a écrit :
The method I use is to reduce the difference between actual speed and
c by a
fixed factor per unit distance.
speed relatively to what ? Ether ?

If you didn't snip MORON, you would see that I plainly stated the
reference for
speed....the binary barycentre..

I'm not talking about emission speed in your so-called 'model'... but
final
speed.

The final speed is c wrt the barycentre. It is c+u wrt Earth where u is
the
speed of the barycentre wrt earth.
Actually it wont be exactly that for other reasons.

It needs to be c/n to explain frequency-dependent
pulse dispersion, and I would presume you would
then say c/n relative to the medium which produces
that refractive index, i.e. the ISM.

Yes it wil be something like c/n...but n is virtually 1 anyway.


George

On Sun, 18 Feb 2007 21:22:04 +0100, "Paul B. Andersen"
wrote:

Henri Wilson wrote:
The only explanation I can suggest is that all large mass centres are
surrounded by some kind of weak EM reference frame....and these extend well
away from the objects themselves.

:-)

The brain hasn't thawed yet, I see.

A little (more) Vodka might help....


Paul

On Sun, 18 Feb 2007 00:27:10 +0000 (UTC), bz
wrote:

HW@....(Henri Wilson) wrote in
:

On Sat, 17 Feb 2007 20:00:07 +0000 (UTC), bz
wrote:

in space. Like I said, we would see everything so clearly.

You might liken it to that effect, but it should be syncronized with the
relative velocity of the source at the time that the arriving photons were
actually emitted.

Clearly they MUST arrive from the position held by the star when those
photons were emitted (modified by aberation, of course).

If the star moves (and many do) significantly between the time the slow
photons were emitted and when the fast photons were emitted, then the
images formed by each would be in significantly different locations in the
sky.

yes but the light still travels through quite similar regions of space.


The photons would NOT merge into a single image any more than the red
and green lights merge into a single white light.

Well you can speculate as much as you like about this bob.
I can't afford to worry about it at this stage.

I suggest that you can not afford NOT to worry about it
because it may, by itself, drain the BaTh of all viability as a model.

The fact that is models many brightness curves is clear support for its
validity.

I do use a 'half distance' model.

Which is 'equivalent' to a half life model IF the velocity is constant.

So, what is the 'half distance' or 'half life' of c+v and c-v photons?

And are they the same?

No they still live.

I assumed they remain but become 'c' photons rather than c+v or c-v
photons.

They approach 'c+u' photons.


Problem or not, something causes my required distances to be
consistently shorter than the hipparcos ones.....and the effect is
period dependent....

Henri, if you take the log of the sum of three sin waves, such as

sumlog(theta)=log(a*sin(theta+alpha)+b*sin(theta+ beta)+c+sin(theta+chi))

and are allowed to set the six parameters a, b, c and alpha, beta and chi
to any values you like, you can produce curves that look like any of the
curves you currently produce with your program.

This does not make the results any more or less significant than the
results of your program.

In fact, as you probably know, you can produce ANY repetitive curve by
summing properly phased and scaled sine wave.

Do you think I'm stupid.
The program operates along very strict lines...based solely on the relative
movement of c+v and c-v light.
There is no way I can fiddle the results.

There could be an entirely different explanation....but 'extinction'
seems the most plausible.

It seems less and less likely, the more I think about it.

Plenty of others think it is very likely. It's not a new idea you know.


One might come to that conclusion if the effect wasn't so consistent.
The plain fact is, the BaTh matches many brightness curves very closely.
The only problem is that the distances are usually too short.

That sum of sines, as mentioned, can do the same.

No it cannot...although I suppose any ellipse is the sum of two sines 90 out.

Of course there are many stars that DO vary intrinsically and maybe
I'm trying to match those with a theory that doesn't apply.

Well said!

Well obviously a proportion of binaries must be eclipsing. ...but a
greater proportion could be explained purely by the BaTh since it
produces very similar curves.
Also it is hard *but not impossible) to explain the presence of
harmonics in a brightness curve on purely 'orbit grounds'....so maybe
many stars ARE huff-puffing.

That is all correct.
The question is how many are actually due to BaTh.
More and more it looks like less and less.

I say the brightness variation of huff-puff stars is still largely a
consequence of the BaTh.

So all double stars (with the right orbital plane) at great distances
should show large brightness variations.

Without unification they would, yes...but they don't...

Exactly.
Actually if the observer lies well beyoind the critical distance, no
brightness variation is to be expected, even without unification.

Beyond means inside or outside????
Too close or too far away?

too far a away....but that shouldn't happen because of extinction anyway..

Either answer would seem to reduce the number of Wilson Variable stars
rather drastically.

Not so, it turns out that many stars in our galaxy have just about the right
velocities and distances to be variable.

Diostance of 100-20,000 LYs, velocities ~0.0001 to 0.000001, periods 1 to 24
months....these are ideal for producing some kind of variability.

That is what I'm trying to explain.

There is a simple explaination: the Ritzian model is wrong. Light always
moves at c wrt all observers, even those in the interial FoR of the
source.


Stick to your religious belief if you wish to Bob.

Oh, my faith is not as strong as yours.

Even SR says an observer will measure the approach of light towards other
moving objects as being different from c. That is what the BaTh is based on.

I keep looking for flaws in my favorite theories. I love to find such
flaws.


There could be other reasons for it.
....face-on orbits for instance.

I did say 'with the right orbital plane'.

Face on orbits would show no doppler shift in either model. We probably
do not even know they are double stars unless they are optically
separable.

We can usually tell by the type of spectrum if two stars are
contributing to a 'point source'.


Only if they are from different stellar families.

which they often are.

"Henri Wilson" HW@.... wrote in message
...
On Sun, 18 Feb 2007 09:31:57 -0000, "George Dishman"

wrote:


"Henri Wilson" HW@.... wrote in message
. ..
On 16 Feb 2007 00:38:58 -0800, "George Dishman"

wrote:
On 15 Feb, 23:15, HW@....(Henri Wilson) wrote:
On 15 Feb 2007 05:33:24 -0800, "George Dishman"
wrote:
On 15 Feb, 12:48, bz wrote:
"George Dishman" wrote
oups.com:
On 14 Feb, 23:29, bz wrote:
HW@....(Henri Wilson) wrote

In that case which non-variable spectroscopic
binaries have you analysed and what wa the
predicted light curve?

George, like I said, the biggest problem for me is to find both velocity
and
brightness curves for the same star.

I asked about non-variable stars!

"bz" wrote in message
.198.139...

The brightness curve looks like this:
----------------------------------------------------





Brightness curves for near circular orbits are pretty well the same so
all
I
need is the magnitude change and maximum velocity.

If you can find some examples for me I will try to match them.

You could ask in sci.astro.research, all you need
is the velocity curve and a paper that says "No
brightness variation has been detected to the level
of *** mag."

There are plenty of reason why no brightness variation will be expected.

Such as?

There appears to be another factor contributing to light speed
unification
other than plain space density of matter.
Maybe this is related to the gravity field of the stars involved. I
have
no
explanation as yet.

Gravity would slightly couteract the speed unification
effect but it is a second order effect so increases the
unification distance by about one part in ten thousand
typically, completely irrelevant as you don't know the
distance to within an order of magnitude yet.

I'm not trying to explain it at this stage. I just want to find a
consistent
pattern. Unification distance appears to be definitely related to orbit
period.

That would suggest a non-linear relation between (v-c/n)
and dv/ds. It still needs to be first order at zero but
perhaps a third order component? Gravity certainly isn't
going to do anything for you.

I'm not so sure of that.

I am.

However the brightness is predicted to go to
infinity at the critical distance when the first double image would
occur.
Since this doesn't seem to happen and multiple images are not commonly
observed, I am prepared to accept that exinction rates are normally
fairly
high.

That's all I meant. Typically it must be no more
than a fraction of a light year.

No. It doesn't work like that. Something makes it period dependent.

It can only be the speed.

...and maybe distance between 'pulses'. Similar really.

Not in the slightest, the phrase "distance between"
has no meaning for a single pulse, speed has. The
only way you can avoid multiple pulses is if the
speed difference decays in much less than the
critical distance.

After all,
you cannot unify light with other light that hasn't yet been emitted.

Nothing of that kind was suggested. The pulsar is an
obvious example, each pulse is 45 us or 13.5 km long
and they start out 2.95 ms or 885 km apart. The highest
frequency shift is 30.54 mHz so over the entire journey,
the faster pulses only catch up by 79.7 m. You explained
this yourself in another post:

"Henri Wilson" HW@.... wrote in message
. ..

The light from these stars still travels throgh similar quality space,
even if it emitted months later.

Eventually the pulses change speed (asymptotically as has
been said) to c/n but it is the 'quality of space' as you
nicely put it that is responsible, not another bunch of
photons 885 km away, and bear in mind too that the speed
doesn't just come to match adjacent pulses but _all_ the
pulses emitted over the 1.5 day orbit end up at exactly
the same speed.

There's plenty time for that to happen, you figure for
the critical distance is 8 light years and the system is
over 3000 light years away.

there is a lot to be done yet George.

You can play with hypothetical theories for ever.

George

On Sun, 18 Feb 2007 15:29:52 -0000, "George Dishman"
wrote:


"Henri Wilson" HW@.... wrote in message
.. .
On Sat, 17 Feb 2007 20:00:07 +0000 (UTC), bz
...
So all double stars (with the right orbital plane) at great distances
should show large brightness variations.

Without unification they would, yes...but they don't...

Exactly.

Actually if the observer lies well beyoind the critical distance, no
brightness
variation is to be expected, even without unification.

I just noticed this in passing, that is not correct
Henry. Brightness variation still occurs but it
grows more slow as the speed difference decays. The
sum under an (inverse) exponential is finite, so
the distance in your program is actually the
integrated effect.

For the pulsar you are modelling for example, if
the area under the speed difference curve adds up
to the same as the initial difference time 8 light
years then the brightness curve will be as you
show here

http://www.users.bigpond.com/hewn/J1909-3744.jpg

even though we are 4000 light years away. In fact
that curve will apply for any Hipparcos distance
more than about 100 light years. In other words,
as long as the observer distance is much greater
than the extinction distance, the D in your program
is actually the latter.

THat is true. The distance required to match a curve IS the extinction distance
(or about 99.9999%)

No distances ever reash the critical one where multiple images appear....or
that's what appears to happen.

I was only pointing out that without extinction, stars at very great distances
should not appear to vary because the number of images should become very high.

I DID consider that this could explain many of the high frequency brightness
variations that are observed - even pulsars - but I dropped that idea.


HTH
George

On 18 Feb 2007 11:38:10 -0800, "PD" wrote:

On Feb 17, 5:12 pm, HW@....(Henri Wilson) wrote:
On 17 Feb 2007 08:54:45 -0800, "PD" wrote:

...
Tell me what is wrong with my derivation...

Nothing is wrong with your derivation. Your conclusion that it implies
circularity is what's wrong.

The rule for combining velocities is not, nor was it ever, used to
assert that the speed of light is constant regardless of reference
frame. The only claim that is made is that the frame independence of
the speed of light is *consistent with* the rule for combining
velocities. Moreover, the experimental evidence in support of the rule
for combining velocities has nothing to do with measuring the speed of
light, but in fact measuring the speed of other particles in different
reference frames -- and it is there that measurements are completely
consistent with the velocity combination rule.

The frame-independence of the speed of light is taken as an unproven
*postulate* in special relativity. It is not necessary in science to
experimentally prove a postulate. One determines the implications of a
postulate (and just as you derived it, the velocity addition rule is
an example of an implication of this postulate) and then tests those
implications against experiment. If the implications match experiment,
and if the postulate is able to generate more successful implications
that match up to experiment than competing postulates, then this is
taken in science to be sufficient grounds for belief in the truth of
that postulate.

In this particular case, the postulate is the frame-independence of
the speed of light. One implication (of numerous implications) is the
rule for combining velocities. The rule for combining velocities has
been tested experimentally in a wide variety of circumstances (without
needing a direct test of the frame-independence of the speed of
light). And because this, and so many other implications, match
experiment so well, we take stock in the truth of the frame-
independence of the speed of light.

....

Well said.

Well, thanks, but Henri will ignore it, since it doesn't feed his
fantasy.

I showed how to derive the formula with trivial mathematical circularity.
Does that make me as great as Einstein ...or greater...?


Well, Henri, as I explained to you in great detail, there is nothing
circular about it. You started with the presumption that c is
constant, independent of the reference frame, and used that derive the
correct rule for the addition of velocities. That is precisely the
right way to do it. Circularity would entail concluding what you
started with, and that is not what you're doing.

Of course I am.
I start with the postulate that w = c and end up with an equation that seems to
CAUSE w to always be c.

.If you will read my
response quoted above once more, you will perhaps understand that a
little better.

PD

"Henri Wilson" HW@.... wrote in message
...
On Sun, 18 Feb 2007 10:59:26 -0000, "George Dishman"

wrote:


"Henri Wilson" HW@.... wrote in message
. ..
On Sat, 17 Feb 2007 14:22:20 -0000, "George Dishman"



Trial and error Henry, you feed what you think is the
true value of v*sin(i) and see whether the curves match
the observations. If not you alter the value until you
get a match and then you have found the value of v*sin(i).
At that point the predicted velocity curve should match
the published curve and you have found the true velocity
which takes into account the effect of ballistic theory
on the Doppler. Isn't that how you use it?

Not exactly.
Unless I have access to a reliable figure for the maximum radial
velocity
I
cannot really come to a firm conclusion about distance or unification
rate.

But you cannot ever get that because the variable
speed messes up the Doppler equation. As with any
modelling technique, you put in your initial guess
of the actual parameters, the program caclulates
the observed signals and then you iterate until
the predicted observables match that actuals.

Ah, but I only need a value for the MAXIMUM orbital speed.

Ah, but you cannot know that, all you know is the
maximum Doppler shift.

The BaTh and SR
doppler equations are effectively the same.

No they aren't, that's the whole point. Look at the
bottom of your reply where you agree the _apparent_
speed should reach c at the critical distance!

I feed in the max value and then try to match the brightness curve. In
doing so
I obtain velocity curves at both the source and the observer.

George, the latest upgrade of my program is now on my website if you would
like
to use it. www.users.bigpond.com/hewn/variables.exe
I have removed most of the bugs although it doesn't have comprehensive
instructions as yet. Extinction doesn't work for circular orbits.

That's OK, your existing distance factor can be
essentially used as the extinction factor as long
as we are observing from a much greater distance.

I really need three quantities, Vmax, distance and magnitude change. I
can
determine yaw angle and orbit eccentricity when matching the basic SHAPE
of a
brightness curve ....if I have such a curve.

All that can ever be observed are the spectral shift
and brightness for normal stars or the PRF for pulsars.
none of your results are valid unless you are working
back from those.

Like I said, all I need is period, distance and a value for the maximum
radial
velocity.

Like I said, what you have is maximum Doppler shift.

For elliptical orbits, this has to be corrected for yaw angle, which I can
determine from curve shape.

Not a problem, this one is circular (you snipped the
figure of ~10^-7 for eccentricity earlier).


The pulses are assumed to move at (c+v)cos(a) towards a distant
observer,
where
a is the angle between the orbit tangent and the LOS.

Rats! I assumed you would ignore the cos(a) term because
the orbit radius is much smaller than the distance to
the system so cos(a) ~ 1.


Sorry that should have been c + v.cos(a) where v is the tangential speed
at any
point and a a function of time.
This merely describes the radial velocities towards the observer from all
points around the orbit.

The point stands, I assumed something incorrect so
my comment was wrong and I understand why you were
confused by it. Anyway it's easy to get round as
I say later, just use 1 light hour for the distance.

Setting the distance to zero is
then equivalent to finding the rate that the pulses hit
a flat plane perpendicular to the line of sight say just
beyond the orbital radius and before any bunching can take
place, or having the right orbital speed but zero radius.

The program then
calculates the arrival times of all the pulses emitted over a number of
orbits
at the observer distance.
At any instant the pulse positions form a regular spatial pattern. As
this
pattern moves past the observer, it gives the impression of brightness
variation. (dn/dt = dn/dx.dx/dt)

Thus, a bunching of pulses shows up as a brightness increase.

That's what I expected. At the distance where the
pulses first overlap (the fast ones catch the slow
ones) you get zero time between pulse arrivals hence
the inverse is an infinite number per second or
infinite brightness. It isn't really infinite as
there are only a finite number of pulses in the
stream but the calculation will go to very high
levels.

That's right. It does....but I have realised that this never happens,
probably
becasue of extinction.

That's why it sets an upper limit to the extinction
distance, the whole point of this excercise.

This is why DeSitter was wrong...and his argument has
always been the only 'evidence' against the BaTh.

No, the Sagnac experiment rules it out, this is only
every going to be a hypothetical curiousity.

Most variations are around 1.5 mag or less.
...and yes, I don't have much faith in the accuracies of many published
figures.

It's not a question of faith, numbers are accurate
but in this case there have only been two measurements
made AFAICS by different groups at different times.
It doesn't really matter, your brightness increase
would just be the number of pulses per second because
each pulse essentially carries the same energy other
than a random variation from pulse to pulse due to
the nature of the source.

If I produce a 'brightness curve' for the pulsar, its height will reflect
the
number of pulses arriving per unit time...not its 'brightness'. Pulsars
are
constant.

Yes, that's why I said I wasn't really interested in
the brightness as such, but it has been helpful in
finding the critical distance.

I'm not sure what it is you are asking me to do.

OK, let's do it in small steps so that I can
give you clear questions.

Common to all: set the eccentricity to zero, yaw
becomes irrelevant. Set the orbital period to
1.5334494503 days.

Step 1. Set the distance to zero (your sim should
reproduce the conventional theory) and set the
actual velocity to 27983 m/s.

Check that the observed velocity curve you get
matches that and that the maximum velocity is
90 degrees after conjunction.

That wont work.
'Zero distance' means 'at the orbit centre'. Radial velocity is
zero...so
is
brightness variation.

....So I'm not with you at all, here.

Understandable, I made an assumption about your
software that wasn't correct. The orbital radius
is 1.9 light seconds so if you set the distance
to one light hour, there should be minimal
bunching as the critical distance (below) is
8 light years and cos(a) = 0.999999861. You
should get the conventional curves to 1 part
in 10^7.

What curve are you talking about George?

The red curve for the apparent speed. If you enter
27km/s the red curve should show that deviation
above and below the white axis. It would help if
you added a vertical scale or we cannot confirm
that. I'm presuming the value in the table on the
left called "Max. Vel." is your assumption for the
actual speed which you entered rather than the
highest point on the red curve.

Not the pulsar curve I hope. I don't claim that is a result of the BaTh at
all.
It's a spinning neutron star.

Step 2. Increase the distance until you just get
the velocity curves going to infinity and tell me
what distance you get.

I assume you mean the 'brightness curves'.

Effectively yes. I should have said the speed goes
to c, not to infinity.

Consider the pulsar at four points in the orbit
round the barycentre '+':

D

A + C Earth

B

The diagram assumes the motion is anti-clockwise.

The highest acceleration towards Earth occurs at
point A. Look closer at two consecutive pulses
assuming they occur equally either side of A:

v - * ~ -- slow, c-v
A-(
* - v ~ -- fast, c+v

At the critical distance, the fast pulse just
catches the slow pulse after 8 light years so
they arrive simultaneously for an observer at
that distance.

Compare that with the conventional view. It says
the maximum Doppler would be at point B. For the
pulses to arrive simultanseously, the pulsar would
have to be moving at c to keep up with the first
pulse and emit the second alongside.

I am guessing that the critical distance should be
around 4 light years but let's see what your program
says before we get on to the more interesting stuff.

Period = 0.0042 years
Velocity = 0.0000933c

Critical distance = ~ 8 LYs.

See: http://www.users.bigpond.com/hewn/J1909-3744.jpg

Note that the observed velocity curve (red) is very different from the
real
curve (blue) at that distance.

I asked and you answered:

2) Have you corrected your program to show the velocity curve
that would be derived from the ballistic Doppler shift?[*]

Yes.

At the point where the brightness goes to infinity,
the time between pulses goes to zero and the velocity
curve (red I think) should peak at c.

That is correct.

That should be
coincident with point A which should be where your
blue line crosses the white axis and is rising.

No it's more subtle than that. the point varies with distance.

I'm assuming you have related the phase back to the
source system. In other words you subtract the mean
time from the barycentre to the observer from the
actual time. Otherwise a few light hours change to
distance would create a major apparent phase shift.

There is second
order term involving the 'rate of change of acceleration'. You have
omitted it.

I don't believe there is such a term but that's why
I want to do the short distance test first.

(I'm having some trouble producing the right colours with Vbasic on
windowsXP).

The colours are distinguishable on the jpeg so I that's
fine. The real concern is with the phase shift between
the blue and others. I'll have to give a little more
thought to the effect of propagation speed on arrival
time but have a think about what I'm saying and see if
you think your program is producing what I expect.

I have looked closely at this myself before.

The point of maximum brightness moves in phase wrt the source velocity
curve as
distance in varied.

You might like to run the 'lightfronts' section of my program. It shows
just
how the pulses move away from the source. Increase the time scale to about
20.

What I might do is try to produce my own version so
I can check what I expect. Your GUI is very unfriendly
or at least it was last time I tried to use it.

In the meantime, we will need to know the speed for
the peak of the red curve in comparison to the number
you enter so perhaps you could consider adding either
a speed scale or a box with the value at the peak like
the max/min brightness box.

George

"Henri Wilson" HW@.... wrote in message
...
On Sun, 18 Feb 2007 15:29:52 -0000, "George Dishman"

wrote:


"Henri Wilson" HW@.... wrote in message
. ..
On Sat, 17 Feb 2007 20:00:07 +0000 (UTC), bz

...
So all double stars (with the right orbital plane) at great distances
should show large brightness variations.

Without unification they would, yes...but they don't...

Exactly.

Actually if the observer lies well beyoind the critical distance, no
brightness
variation is to be expected, even without unification.

I just noticed this in passing, that is not correct
Henry. Brightness variation still occurs but it
grows more slow as the speed difference decays. The
sum under an (inverse) exponential is finite, so
the distance in your program is actually the
integrated effect.

For the pulsar you are modelling for example, if
the area under the speed difference curve adds up
to the same as the initial difference time 8 light
years then the brightness curve will be as you
show here

http://www.users.bigpond.com/hewn/J1909-3744.jpg

even though we are 4000 light years away. In fact
that curve will apply for any Hipparcos distance
more than about 100 light years. In other words,
as long as the observer distance is much greater
than the extinction distance, the D in your program
is actually the latter.

THat is true. The distance required to match a curve IS the extinction
distance
(or about 99.9999%)

No distances ever reash the critical one where multiple images
appear....or
that's what appears to happen.

I was only pointing out that without extinction, stars at very great
distances
should not appear to vary because the number of images should become very
high.

Yes but you also then get a very odd effect on the
spectrum which isn't seen either. The extinction
must always be much less than the critical distance.

George

"Henri Wilson" HW@.... wrote in message
...
On 17 Feb 2007 21:55:33 -0800, "Leonard Kellogg"
wrote:


Henri Wilson wrote:

Anyway, put the numbers into your program and tell
me what you get and then we can discuss their
interpretation. Check the results for zero distance
first and make sure you get the right speed and phase.

Naturally for zero distance I get no brightness variation.
The observed velocity is in phase with the true velocity.

You should still get a very small variation due to the
conventional bunching you reminded me of at the top.

Not if the observer is at the orbit centre.

He isn't saying to put the observer at the orbit centre, he
is saying to locate the observer just in front of the light
source so that your program output shows the effect of the
initial bunching of the pulses due to the changing position
of the star, but not the bunching which occurs in transit.

At each iteration, the observer is at zero distance from
the source, but is treated as being motionless, as usual.
It is as if there were 30,000 observers round the orbit,
each motionless relative to the orbit centre, but placed
immediately in front of the source.

If your program is unable to do that, you should be able to
put the observer at the near side of the orbit. Apparently
you have simplified the program to treat an orbiting star
as a reciprocating point, oscillating back and forth in the
line of sight. Just place the observer at the near end of
the stroke.

I can't see the point.
There wil be no opportunity for bunching and no brighness variation.
All I will see is conventional doppler frequency variation using constant
c.

That was the entire point of the exercise, to check
the code by confirming that your program gives the
conventional result when there is no opportunity
for bunching.

George