author: Mike Dworetsky

subject: Re: Discovery of PLuto ...

text:
"wnowak" <[email]> wrote in message
news:[email]...

It's sometimes hard to explain why something was not noticed for a long
time, but the usual answer is, no one looked hard enough, or possibly Charon
was occasionally seen, and dismissed as a flaw or background star.

Pluto was not regarded as a subject of great interest by most astronomers in
the '40s and '50s,  except for the question of its size and mass.  The best
way to look for evidence of mass was to measure deviations in the orbits of
Uranus and Neptune, so observational approaches were directed at accurate
observations of these other planets.

Back in the 1960s an effort to observe an occultation of a star by Pluto
produced upper limits for its size, and showed that Pluto was much smaller
than Earth, but Charon did not happen to occult the star for any observer.

You also have to remember that most photographic observations of Pluto were
done to determine or improve its orbit, so only relatively small telescopes
were used, such as astrographs, or long focus refractors adequate for the
task but often located in places with relatively poor seeing.  Charon is
always within a second of arc or so of Pluto itself and would be extremely
hard to spot on such photographs.

It was only when Christy used a relatively large (1.5-m, ISTR) telescope to
get precise astrometry from a high-quality mountaintop site (for prediction
of possible occultations) that he noticed a small bump on one side of the
planet's image.  He might have simply dismissed it as a background star or a
flaw, but because it was on several images in different positions he
realised it was a satellite.

This said, I recall that Gerard Kuiper observed Pluto visually with the
Palomar 5-m telescope in the late 40s or early 50s, on a night of excellent
seeing. He wanted to measure the diameter with a bifilar micrometer (or
similar), and it is slightly surprising that he did not spot Charon.  Or
maybe he did, and dismissed it as a faint background star.  Remember, this
was a single observation on one night.


author: Jonathan Silverlight

subject: Re: Discovery of PLuto ...

text:
In message <cv1r0o$saj$[email]>, Mike Dworetsky
<[email]> writes

Interesting stuff snipped.

Can you imagine the feelings of astronomers if Charon hadn't been
discovered until 1990, and they realised they had missed a series of
eclipses which won't recur for over a century? :-)


author: wnowak

subject: Re: Discovery of PLuto ...

text:
I am curious. Do you remember the exact time of GK observations, or maybe you
can ask around ? I can calculate the exact angular distance between P and CH and
add this fact to my site

http://www.interlog.com/~wnowak/book

So far I thought that I knew everything about PLuto, but you proved me wrong :)
BTW, no observations of PLuto ( for sure no Charon :) with 2.5 meter Mt. Wilson
telescope in 1930s, 40s ?

Excellent seeing in California in 1930-50 would be 0.30 arcsec. right ?

WN.

Mike Dworetsky wrote:


author: [redacted]

subject: Re: Discovery of PLuto ...

text:
Jonathan Silverlight writes:

Yes I can, because when the satellite was discovered in 1978, the
orbit was known to be nearly edge on, but it was not known whether
it was opening or closing, thus there was a 50 percent chance that
the eclipses had been missed.


author: Steve Willner

subject: Re: Discovery of PLuto ...

text:
In article <[email]>,
 wnowak <[email]> writes:

Seeing that good would would be exceptional even at Mt. Wilson, and
Palomar on the whole is a bit worse than Mt. Wilson.  A quick web
search turns up a cookbook for one of the CCD cameras at Palomar.
According to the author, "The seeing at Palomar is typically ~1.0 to
1.5 arcseconds FWHM, sometimes as good as 0.8 to 0.9 arcseconds."
That accords with my own memory from the 1970's.

See also http://www.chara.gsu.edu/CHARA/Reports/tr13.pdf , which
cites reports that the seeing is seasonally dependent.  My guess
would be that March is probably around average.

A more thorough search may turn up other reports.


subject: Re: Discovery of PLuto ...

text:
"wnowak" <[email]> wrote in message
news:[email]...
you
CH and

If you do a search on the ADS you will find Kuiper's paper in the 1950 Publs
of the Astr Soc Pacific, v. 62, p133.

He states he was unable to get an accurate measurement on the Texas 82-inch
telescope owing to the faintness of Pluto.  The equipment used was a disk
that simulated the angular diameters of stars or small objects (not a
micrometer).  The measurement was therefore a direct comparison of visual
appearances.

He moved to the 200-inch telescope and observed on the night of 21 March
1950 as a guest of M. Humason.  The angular diameter was found to be 0.23
arcsec (0.20 if some corrections were taken into account).  This was so
small as to be a genuine surprise to some, because it meant that the mass
could not be as large as the 1 Earth-mass others were deriving from the
orbit of Neptune ( which of course turned out to be spurious).

He had Milton Humason check his observations at the telscope and they
independently observed the same value via the direct comparison disk device.


subject: Re: Discovery of PLuto ...

text:
[email] wrote:

Hmm ... that is in contradiction with what Stern says in his book;

"... However, the fact that no observer had accidently stumbled onto one
in progress hinted it was more likely that the event were in future, than
in the recent past. " ( page #66 )

This suggests 50% ++,  correct Mr. Tholen ?

To tell you the truth I do not quite understand what Stern is talking
about.
For sure you know, since your picture is in the same book a few pages down
the road. Please explain this to us.


subject: Re: Discovery of PLuto ...

text:
In article <cv71bm$je$[email]>,
 "Mike Dworetsky" <[email]> writes:

Thanks, Mike.  A few salient quotes:

"fine seeing, about 6 on a scale of 10."  Hard to know what this
means.  If I had to guess, I might put it at about 0.9 arcsec FWHM.
But this is just a guess.

The observation was made 1950 March 22, 4h UT.  Anybody care to
calculate the separation of Pluto and Charon at that time?  Kuiper
gives Pluto's distance as 35.56 AU.  Is the modern value any
different?  Kuiper also gives a zenith distance of 20 degrees.  Is
that consistent with the time of observation?

With the modern Pluto diameter of 1195 km and Kuiper's distance, the
correct value should have been 0.046 arcsec (if I've done the
calculation right).


subject: Re: Discovery of PLuto ...

text:
Mike Dworetsky writes:

That depends on the wavelength.  In visible light, Charon is 5.5 times
fainter than Pluto.  That's less than two magnitudes.


subject: Re: Discovery of PLuto ...

text:
wnowak writes:

I don't buy the argument.  There wasn't a whole lot of accurate
photometry being done prior to the discovery of the satellite.
The events themselves lasted only about five hours, and that's
for a central event (less for the grazing events).  With two
events per orbit and one orbit every 150 hours, you're talking
one part in 15.  That is, if someone were making random observations,
there's a 94 percent chance that the observations would be at times
when no event was occurring.  But as I said, there weren't a whole
lot of observations being made.  I'd have to dig into the literature
to count the number of photometric points obtained in the 1970s,
but I'd guesstimate 30.  If events were occurring, that's two
potential observations at the time of events.  They could have been
easily dismissed as bad points.  Furthermore, I don't know of
anybody who was taking high time resolution observations of Pluto
in the 1970s.  You'd need several points during an event to see
the trend.  A single low point could be easily dismissed as a
faulty observation.

Meanwhile, there is also a claim in the literature that events were
seen when we now know there could not have been events, which
demonstrates that faulty observations can be made.

I hope the above is sufficient.


subject: Re: Discovery of PLuto ...

text:
Steve Willner writes:

I did so once a long time ago, when this same topic was being
discussed.  As I recall, the value didn't lead to any conclusive
result, but I don't remember the exact value.  Extrapolating an
orbit with a few year arc back for over 30 years is going to
have some uncertainty associated with it.  Perhaps after I get a
chance to do a global solution with data spanning nearly two
decades, an extrapolation to 1950 can be regarded as fairly
certain.

It's close enough.

Yes.

Radius, not diameter.  And 1195 is too big.  Probably no smaller
than 1150, however.


subject: Re: Discovery of PLuto ...

text:
[email] wrote:

For what  value of PLuto's albedo ?


subject: Re: Discovery of PLuto ...

text:
[email] wrote:

Yes it is, and I agree 100% or to be more precise ( 50 + 50)% :).

Talking about eclipses of PLuto and Charon, Stern says
"... Then exactly- half a Charon-orbit later - 3.194 days after Binzel's first
event, on February
20th, another young astronomer, the University of Hawaii's David Tholen, caught
Charon falling in PLuto's shadow, ...".
Binzel's and your discovery exactly 20 years ago. Happy anniversary :)

I understand that above you are referring also to observations made a month
earlier on 16th of January by Buratti and Tedesco, correct ?

So, we have a very precise date of the start, however the end is somehow not
clear. Some
sources say 1991, some other say 1990. Why is it like that ? The end was also
important since it would help us to calculate the precise date of the P+CH
equinox. Nobody rally cared to look for the end. People got tired :)?


subject: Re: Discovery of PLuto ...

text:
In article <P%NSd.8245$[email]>,
 [email] writes:

Argh!  Yes, radius.  Thanks, Dave.  (You can tell who is the expert
and who just looks things up in AQ.)  So call it 0.09 arcsec true
diameter against Kuiper's claimed 0.20 arcsec.  Not bad, really,
considering the difficulties of the measurement.


subject: Re: Discovery of PLuto ...

text:
wnowak writes:

Pluto's albedo is a strong function of both rotational phase and
wavelength.


subject: Re: Discovery of PLuto ...

text:
wnowak writes:

Those observations are more controversial.  Originally it was suggested
that an event had been seen, but it was later discovered that the CCD
dewar had run out of liquid nitrogen and had started warming up, after
which the data were considered suspect.  After the time coincidence with
the Feb 17 and 20 events was noticed, the Jan 16 data were once again
put forward as representing an event.  However, the data show an event
that is deeper than the Feb 17 event, despite the fact that we now know
from the orbit determination that less surface area was occulted on Jan
16 than on Feb 17 and therefore could be no deeper than the Feb 17 event.
Also, the event was not very symmetrical.  In other words, the data were
once again considered suspect.  What is certain is that observations
were being made at the time of an event on Jan 16.

Not at all.  I looked for the end as vigorously as I looked for the start.
They ended in 1990, twice.  Prior to opposition, there were eclipse events,
but eventually Pluto's heliocentric motion caused the events to end as
seen from the perspective of the Sun.  The Earth moved to the other side
of its orbit fast enough to move back into the region where occultations
could still be seen, thus events resumed after opposition, and then
ended again as the Earth started back over to the other side of its
orbit, moving out of the occultation region.  There were no events in
1991.  There were also no events near opposition in 1990.  I have a
lightcurve taken in May that is flat to a couple thousandths of a
magnitude.  They put a very tight constraint on the sizes of the two
bodies.


subject: Re: Discovery of PLuto ...

text:
Steve Willner writes:

Some of the earliest speckle measurements of the diameter also came
out too large.  I recall values of 3000 and 4000 km being published,
with some model dependency due to the assumed amount of limb
darkening.


subject: Re: Discovery of PLuto ...

text:
[email] wrote:

My point is that in 1950 the polar regions of PLuto were visible from the
Earth, that are
more reflective as far as I know. So, in spite of the fact  that PLuto was
fainter, the relative difference of brightness
between two objects could have been above 2 mag. making it a bit more
difficult to discover a moon.

Also, please remember that PLuto was farther so the max. angular distance was
... let me calculate ... .
~ 0.74 arsec ? If these guys were not lucky, and observed at min. angular
distance then it takes us down to ...
~ 0.66 * 0.74 = 0.49 ! This  is probably just a  bit too little. Once I have
time,  I will use HORIZONS again to verify
for the date of 21st of  March 1950, or maybe somebody else is interested in
doing this.
Any volunteers ? :)


subject: Re: Discovery of PLuto ...

text:
[email] wrote:

This confirms what I have checked with HORIZONS online software.
This also contradicts Stern again. He says 1991. Where does he have the data from ?
The logical question here is; what was the date of equinox, and how precisely we know
that ?
The perihelion date is stated as 5th of September 1989. I did not find the date of
equinox
mentioned anywhere.


author: William C. Keel

subject: Re: Discovery of PLuto ...

text:
[email] wrote:

I recall a correspondence between a fellow grad student and Pete Worden
just after Worden had been involved in such speckle work, about whether
they had misinterpreted speckle amplitudes affected by Charon as
part of the disk. I can't remember whether there was a consensus
on the point, though.

Bill Keel


subject: Re: Discovery of PLuto ...

text:
wnowak writes:

Suppose the pole of Charon is also brighter?  All we know is that there
isn't much variation in brightness of Charon as a function of longitude.
We have practically no information on the variation in brightness as a
function of latitude.

On the other hand, the minor axis of the projected orbit was larger,
so Charon didn't get as close to Pluto.


subject: Re: Discovery of PLuto ...

text:
wnowak writes:

How did HORIZONS confirm when events ended (twice) in 1990?

He doesn't.

1988.  A more precise date is in one of my papers, which I do not have
at home.

I recall it being mentioned in one of my AJ papers that computed when
events would occur for that year.


subject: Re: Discovery of PLuto ...

text:
William C. Keel writes:

If speckle was able to resolve the disk, splitting Charon from Pluto
should have been a piece of cake.  I recall using Weigelt's speckle data
for some of my earliest orbit solutions to predict the onset of mutual
events, so they explicitly solved for Charon's location in their work,
and still came out with too large a diameter for Pluto, though their
result was the smallest of the speckle estimates.


subject: Re: Discovery of PLuto ...

text:
[email] wrote:

I agree that Charon can also have brighter polar regions. Maybe also atmosphere
?
They say there is still a chance for that. In this case it would  be the
smallest object with the
atmosphere. On 11th of July this year there is going to be an occultation of the
15th mag.
star by Charon observable from the location of big Chilean telescopes. There is
a www site
for that, do not remember the exact address; you must "GOOGLE" it :)


subject: Re: Discovery of PLuto ...

text:
[email] wrote:

I did not say that I confirmed with HORIZONS  "double ending". All I say is that I
confirmed
that it did not happen in 1991. If I am not mistaken it was 0.01 arcsec. short of contact
of discs
of two objects, again if I am not mistaken it was at the end of August 1991.
As for equinox 1988 is not a very precise date, isn't it ? Simple calculation from
1990-1985/2 + 1985 rather suggests 1987.5 :)

One more question. In a long run the orbit of P. is chaotic, however in a short run it
librates.
In Stern's book he provided a diagram with librations of P. in relation to position of
Neptune.
He made a mistake there p.143 ( again ? ), since when you calculate the total number of
loops
( 60 ) it covers 15000 years, and not 40000 as he says.

The question is. What is the direction of librations ? Are the equinox and perihelion
points coming closer now, or they are going to be more separated with every next perihelion
?


subject: Re: Discovery of PLuto ...

text:
wnowak writes:

There is an occultation this July that may be able to answer that
question.

That is by no means certain.  The nominal path crosses Brazil, last I
heard.

Not me.


subject: Re: Discovery of PLuto ...

text:
wnowak writes:

I'm not following you.  It was 0.01 arcsec for what?

Best I can do with limited time and what I have at home.

A bit too simple.

Why do you say it's chaotic?  Long integrations of Pluto's orbit show it
to be fairly stable.

I'd have to look at it.

Again, I'd have to look at it.  Not a high priority for me right now.


subject: Re: Discovery of PLuto ...

text:
[email] wrote:

The angular distance that I am talking about is a minimum distance between the edges of
two discs in 1991. Since at that time the orbit was visible as a very narrow ellipse, two
objects were passing by each other every half period, coming very close to each other. Since
the Earth
also moves on its own orbit, it also has an impact on the size of the visible ellipse. So,
what I
discovered is that the best chance for eclipse was in August or early September ( if I
remember correctly ), but
still it was not enough for two discs to "touch each other". At least based on HORIZONS :)

The orbit of PLuto is chaotic; it was confirmed with the simulation of the Solar System
software
in 1985 ?, 1990 ?  In this case PLuto could have been a satellite of Neptune, what
astronomical
community rejected based on the argument that two objects are too far from each other.
Random walk could have placed PLuto where it is now.
High density of PLuto is one of  factors, plus the fact that it seems to be too big as a TNO,
what astronomical community tried to "deny" for  the last 13 years, assuming very low
albedoes ( 4% ) for newly discovered TNOs. What turns out to be wrong after all.

I am afraid that we cannot say if perihelion and equinox points are coming closer, or there
are going to be more separated with
every next perihelion/aphelion. I am afraid that current astrometry is not precise enough to
answer this question. Although I am not sure, so I asked the question.

Stern made a mistake on the diagram; no need to check this. He confirmed that.


subject: Re: Discovery of PLuto ...

text:
wnowak writes:

A separation of 0.01 arcsec is most certainly enough for an occultation;
Pluto was 0.11 arcsec in diameter and Charon was 0.05 arcsec in diameter.

Reference?  Such a result contradicts the integrations of other researchers.

And what mechanism is proposed to get Pluto out of orbit around Neptune?

The astronomical community hasn't tried to "deny" Pluto's size.

Why is it important?

It's not a matter of astrometry.  The current astrometry is sufficient
to say when the equinox occurred and when perihelion occurred.  Future
astrometry should be no worse.  How the orbit evolves is a matter of
accuracy in the orbit integration software.

Where?


subject: Re: Discovery of PLuto ...

text:
[email] wrote:

Please do not place your short comments "after my coma", because you are missing the meaning of
my sentence(s).
Please read my message to the very end, and then comment on it.

Here is the link to the site about Charon's occultation. I think it is going to be very
interesting.

http://www.iota-es.de/charon2005.html

Is this is the one that we are both talking about ? There is Chile in the path of the event.

Re:The size of Pluto; Again, please read my message carefully ( and to the very end ) before
commenting. I am talking there
about RELATIVE  size in comparison to TNOs, and not the absolute size.

Re:The 0.01 arcsec distance; Again, please read my message carefully ( and to the very end )
before commenting. I am talking
there about the distance between EDGES of discs, and not the distance between  geometric
centres of discs of PLuto and Charon.

How Pluto ( assumed moon of Neptune ) could have been taken out of Neptune's orbit ? Here is
one of possibilities.
http://www.astro.rug.nl/~mwester/aos/aose.html

You have mentioned the orbit integration software for calculation of the orbit of Pluto. Any
software works based on the same
basic principle;  "garbage in - garbage out",
no matter how good the software is, therefore quality of  astrometric data entered into the
software is very important.
I still do not know if prediction of which way the "perihelion/aphelion points are moving" is
possible based on the current data
( that covers only as little as1/3rd of the orbit ).

Why it is important ?  Because I thought that maybe this was the reason why some sources say
249 years and some other 248 years for the period of PLuto. If  PLuto was librating "forward"
it would reach the perihelion point faster, right ?
Maybe they are talking about "sidereal - equinox to equinox" and "synodic-forward", or
"synodic-backward" ( perihelion to perihelion ) years of PLuto ? Or, maybe nobody really
thought about that so far ?

Considering chaotic orbit of Pluto. Here is the link.

http://www.fortunecity.com/emachines/e11/86/solarsys.html

The orbit was confirmed to be chaotic many years ago, before the discovery of TNOs, and of
course you know that.

"...In 1988, Sussman and Wisdom produced integrations using the Orrery which revealed that
Pluto's orbit shows the tell-tale signs of chaos,
due in part to its peculiar resonance with Neptune.
...
If  Pluto's orbit is chaotic, then technically the whole Solar System is chaotic, because each
planet, even one as small as Pluto, affects the
others to some extent through gravitational interactions. But we now realize that although
chaos means that some orbits are unpredictable, it
does not necessarily mean that planets will collide - chaotic motion can still be bounded. In
1989, Jacques Laskar of the Bureau des Longitudes
in Paris published the results of his numerical integration of the Solar System over 200
million years. These were not the full equations of
motion, but rather averaged equations along the lines of those used by Laplace. Unlike Laplace,
however, Laskar's equations had some 150,000
terms. Laskar's work showed that the Earth's orbit (as well as the orbits of all the inner
planets) is chaotic and that an error as small as 15 metres
in measuring the position of the Earth today would make it impossible to predict where the
Earth would be in its orbit in just over 100 million
years' time...."

I am afraid that the  discovery of TNOs made PLuto's orbit even more chaotic.

RE: Stern;  He communicated his mistake to me personally. He "pointed his finger" at R.
Malhotra.


subject: Re: Discovery of PLuto ...

text:
wnowak writes:

Were in you a coma?

I can read your message to the very end and then place my comments in
the relevant locations.

So do I.

Same event, different prediction.  I don't know why it says that it's
based on a recent ephemeris by Standish and then references DE406
when the recent ephemeris by Standish is DE415.

I can read your message to the very end and then place my comments in
the relevant locations.

No, you're talking about using HORIZONS to determine when the eclipses
should have ended.

I can read your message to the very end and then place my comments in
the relevant locations.

That requires knowledge of the sizes of the two disks.  What sizes does
HORIZONS use?

Well, I don't put much stock in an analysis that uses "the mass of Pluto
is taken as the estimated combined mass of Pluto and Triton".  Sort of
like taking 2 = 2 + 2

The quality of the integration software itself is very important.  You
can still get garbage out even from good data in.

There are various ways to define a period.  For the Earth, there is the
tropical year, the sidereal year, and the anomalistic year, among other
possible definitions.

You have to check the individual references.

Well, that link considers the orbit of the Earth to be chaotic.  Could
be a matter of different definitions of chaos.

No, I don't know that the orbit was confirmed to be chaotic.

   "This does not mean, however, that the resonance is unstable or
   that Pluto and Neptune could ever collide, even though their
   orbits intersect."

Actually, their orbits do not intersect.  They cross in the x-y plane,
but there is separation in the z dimension at the crossing point.

How so?


subject: Re: Discovery of PLuto ...

text:
[email] wrote:

Should I understand that here you are referring to my English, by saying this;

"Were in you a coma?"

If this is the case then, it is really, really, very, very  "low blow" as for a scientist. I hope
that you understand
that English is not my first language, besides in this particular case I did not make a grammar
error, it was a typing mistake
( coma instead of comma ).

Please note that I treat you with respect, in spite of the fact that so far you did not answer
any of my more complicated questions
( including even a simple one about the date of equinox ),  and now I feel that you try to
underline your superiority
( using all possible means :).

Is your role on this news-group really to answer only very, very basic questions, like the
difference between
the tropical year, sidereal year, etc. that everybody can find out in two minutes  using the
internet?


subject: Re: Discovery of PLuto ...

text:
wnowak writes:

It was a low blow for you to accuse me falsely of missing the meaning of
your sentences.

You falsely accuse me of missing the meaning of your sentences and you
feel like that's a sign of respect?  You try to dictate how I construct
my replies and you feel like that's a sign of respect?

That's not a complicated question.  I made it quite clear that the
answer is in an AJ paper of mine, and I made it quite clear that I
do not have a copy of that paper at home.  You haven't explained
why the exact date is of such importance to you.

What you feel is irrelevant.

I see yet another sign of your concept of "respect".


subject: Re: Discovery of PLuto ...

text:
[email] wrote:

I have just looked at all our conversation from the very beginning.

You did not tell me a single ( substantial ) thing, that I did not know before. Even details about
the
observations of mutual events in January 1985 are described in Stern's book ( page 70 - including
the fact that B&T CCD had been running low on coolant ).
Now try to counterbalance it with facts that I passed to you. Chaos of the orbit of PLuto that you
have never heard about (?), theory of collision of PLuto and Triton, facts about 11th of July 1995
occultation, Stern's errors,  etc.

Now put on the scale a fact that you are a professional astronomer, and I am say an amateur one.
Add to that the fact that English is your first language ( I assume  not the only one, "sign of
respect" :), and I use English as a "tool". Add to that my long responses with addresses of links
etc. etc., and your short "half-sentences" between lines "after my commas" , like "How so ?", "So
do I.", "Where ?", "He doesn't."  etc.

For all my effort I got a "low blow" in return, when I tried to correct your obvious
misinterpretations of my responses.
I say again clearly ...  obvious misinterpretations of my responses, that everybody who was
watching this conversation must have noticed.

My question is. Why do you think, that I owe you respect ?

I am not going to go as low as you went in your last response; say that it is a bit below my
personal "line of dignity".
I wish you perfect skiing from Mauna Kea in the morning, and surfing the Pacific Ocean in the
afternoon.


subject: Re: Discovery of PLuto ...

text:
wnowak writes:

Then why are you continuing the discussion if you know everything
already?

Did Stern's book also tell you that the event was deeper than it
should have been?  Or is that information not substantial in your
mind?

You're erroneously presupposing that I never heard about the
alleged chaos.  Get back to me when you have a Lyapunov exponent.

You're erroneously presupposing that I never heard about the
hypothesis.  There are other hypotheses.  All have problems.

On what basis do you call your information "facts"?  Your "facts"
refer to DE406 despite there being DE415 specifically done for
the Charon occultation.  I know the people working on the
occultation prediction.  I'm working with them, including Standish.
I'm working on improving the orbit for Charon.  The nominal path is
farther north across Brazil.  But that's probably not sufficiently
substantial for you either.

Etc.???

One that hasn't answered the simple question about what you need all
this information for.

Use English to communicate your reasons for asking all the questions
and why you need to know the date of the equinox down to the day.

You're erroneously presupposing that those are "half sentences".

There's hardly much effort involved in asking question after question
without explaining why you need the information, especially when you
claim to have already known all the answers previously!  Well, have
you figured out yet whether the period of 248 or 249 years is
osculating or not?

They have noticed how you still haven't explained why you need to
know the date of the equinox down to the day, for example.

Are you now trying to justify the way in which you told me how to
format my responses, and accuse me of not reading to the end, on
the grounds that you don't owe any respect?  Is that your
justification for believing that your information represents the
"facts" about the July Charon occultation?

You're erroneously presupposing that I went low.

But telling someone how to format their responses isn't, or to
read to the end, for that matter.

You're erroneously presupposing that I do either.


author: Art Deco

subject: Re: Discovery of PLuto ...

text:
Tholenator(tm) <[email]> tholed:

Lovely kookdance today, Tholenator(tm).  You may continue.


subject: Re: Discovery of PLuto ...

text:
[email] wrote:

There is no darkness but ignorance.
W. Shakespeare

http://www.interlog.com/~wnowak/book


subject: Re: Discovery of PLuto ...

text:
wnowak writes:

I see that you didn't answer any of my questions.  No surprise,
really.


author: Stuart Dawson

subject: Simple robot manufacturing application?

text:
First, I know zippo about manufacturing (I'm a civil engineer and land
surveyor) so please excuse me if I ask any particularly dumb questions.

I'm looking at the possibility of setting up a robot to perform a simple
pick-and-place / sorting operation. It will need to select small 1" * 1"
* 1/4" plastic or metal tiles individually from specified positions from
one tray or feed and assemble them in a specified order and orientation
on a receiver tray about 36" * 36". Repeatability and accuracy required
are not particularly high - 1-2 mm would do OK.

It may also have to take images of the input tray with, I imagine, a
digital camera, and relay them back to the controlling computer.

None of this is (yet, anyway) "mission-critical", nor warrants any great
expense; it's more proof-of-concept, so I'm maybe looking at tracking
down a used machine or even a "hobbyist" solution.

My question, basically, is: what type of machine will do this? I've
spent a little time on the Web and found two apparently suitable
configurations - the SCARA machine and the XY table, but I don't know
enough to take it much further

Any advice, opinions, URLs welcome.

Thanks


author: cncrouter

subject: Re: Simple robot manufacturing application?

text:
Do a search on ebay for robot then have it sort by highest price and you
should be able to find what you need for around $1,500.00
Robert

"Stuart Dawson" <[email]> wrote in message
news:[email]...


author: Sporkman

text:
SCARA is a very viable solution . . . and very expensive.  XY linear
actuators are also viable and perhaps (a little less likely but still
possible) a combination of indexing table with a single linear
actuator.  But degree of viability depends on the size of the table and
also how quickly you need assembly to occur.  The faster and more
complicated the requirement the more expensive the solution.  Almost any
small automation company (like mine) can put together for you an XY
table or indexing table and with software to drive it, but once again,
that's not inexpensive.  I'm afraid I'm not familiar with prepackaged
solutions, but you have some search terms now to use and that's how I'd
urge you to proceed next.  More search terms can include "linear
actuator" and "end effector" (you'll probably want to use a simple
vacuum cup to pick the tiles up).  Likelihood is in order to save much
money you'll have to put components together yourself.  An air
compressor is one expense that you likely won't be able to bypass,
although there ARE electric vacuum units (also not inexpensive).  One
thing for certain . . . if the robot can pick the tiles up from ONE
single location (like a stack) your solution will be much simpler and,
therefore, cheaper.

Mark 'Sporky' Stapleton
WaterMark Design, LLC
www.h2omarkdesign.com

Stuart Dawson wrote:


author: Bill Price

text:
Do you know about http://www.thefirst.org/jefft/voxels/index.html ?

"Stuart Dawson" <[email]> wrote in message
news:[email]...


author: datalines

text:
I'll give you some code, a schematic, and bill of materials
to control a simple DC linear actuator (12V), and you can go from there.
email me for price:

[email]
Stuart Dawson <[email]> wrote in message news:<[email]>...


author: Peter Swanson

text:
As you are in the UK, we could offer the "pre-packaged" solution - see
http://www.intertronics.co.uk/products/xrobot.htm.

Regards,
Peter

On Sat, 13 Mar 2004 09:57:55 +0000, Stuart Dawson
<[email]> wrote:


subject: Re: Shuttle SRB videos

text:
Rocky Top wrote:

It's also video, whereas I believe the Saturn staging shots were 16mm
film.

Maybe they can stick HD cameras on the next one :).

    Mark


author: snidely

subject: Re: Shuttle SRB videos

text:
Scott Hedrick wrote:
[...]

Yes, on the NASA site mentioned above, the 2 links for "left srb" video
and the 1 link for "srb sep combined" are quicktime files directly
downloadable.

/dps


subject: Re: Shuttle SRB videos

text:
I get a 403 Error when I try to access right_aft_srb_camera.wmv (though
right_forward_srb_camera.wmv doesn't seem to be giving me any
problems).  Could you make sure the permissions on this file are set
correctly?

Oh, and thank you, by the way.  You made my day!  :)


subject: Re: Shuttle SRB videos

text:
Vetty vetty nice thank you..............Doc
Chuck Stewart wrote:


subject: Re: Shuttle SRB videos

text:
Scott Hedrick wrote:
[...;]

3 of the links were to .mov's you can save to disc,

at 9, 13, 13.5 mb

/dps


subject: Re: Shuttle SRB videos

text:
OM wrote:

Rats, the mutimedia page's link to the WMV for SRB SEP is 320x240, and
isn't the SRB cam.  (Not sure if they meant it to be pastiche, or if
akamai added their own touch.)

/dps


author: Jeff Findley

subject: Re: Shuttle SRB videos

text:
"Pat Flannery" <[email]> wrote in message
news:[email]...

Here's the NASA page directly (Spaceref seems to have some stale links):

http://www.nasa.gov/mission_pages/shuttle/news/index.html

The composite view (all four SRB cameras) of SRB separation is extremely
cool.

Jeff


subject: Re: Shuttle SRB videos

text:
In the replay from the aft left SRB (I think) you can see what looks
like ice coming off from somewhere around the nose of the orbiter and
moving back, passed the hatch and disappearing over the left wing.  Is
this ice and if so where is it coming from?  (an intensive look doen't
show any distinguishable cross over from the ET????)...........Doc
Pat Flannery wrote:


subject: Re: Shuttle SRB videos

text:
Pat Flannery wrote:

Saw that at the MMT briefing two nights ago when it was first aired,
and you could hear the audible gasps from the room full of jaded
journalists.

It's a stunning bit of footage and I wouldn't be a bit surprised if
this became THE new iconic spaceflight clip, on the order of the Saturn
IB staging or Saturn V gantry-cam liftoff films from the 60's.

Good stuff and just the type of thing that keeps a taxpaying public
happy with spaceflight. For a few minutes anyway.

Frank


subject: Re: Shuttle SRB videos

text:
Fantastic stuff.  Several things were standouts I thought.  Watching
the sound suppression system on the pad from that angle and the
attenuation of the SSME's exhaust through the duct was very cool.  The
smoke trail from the solids seem to hang in the atmosphere much higher
than I thought it would.  Sep from the ET/Orbiter way way fast.  A lot
more debris than I've seen before.  ( much wire or cable)  Descent to
the water was very fast, and upon impact what looked like a whole bunch
of "slurry" in the water (probably burned out solid fuel).  the
underwater shots with the aft camera alone was worth the price of
admission.  (and still more wire or cable floating around on screen)
Great Stuff..................Doc
        [email] wrote:


author: OM

subject: Re: Shuttle SRB videos

text:
On 12 Jul 2006 10:16:18 -0700, "[email]"
<[email]> wrote:

...With audio in Sensurround! :-) :-)

				OM


author: Chuck Stewart

subject: Re: Shuttle SRB videos

text:
On Tue, 11 Jul 2006 08:16:12 -0700, addams013 wrote:

Oops...
Fixed.
...sorry 'bout that :)

The Penguin Liberation Front has struck again!


author: Henry Spencer

subject: Re: Shuttle SRB videos

text:
In article <[email]>,
snidely <[email]> wrote:

And if you click on the picture on the original spaceref page, you get an
MPEG.  (Imagine that, somebody actually using a *standard* format instead
of Microsoft/Apple proprietary garbage...)


author: Scott Hedrick

subject: Re: Shuttle SRB videos

text:
"snidely" <[email]> wrote in message
news:[email]...

Not on the NASA site, and the Spaceref site tried to save "index.html" when
I tried "Save Target as", since the NASA page was screwed up.


subject: Re: Shuttle SRB videos

text:
"Jeff Findley" <[email]> wrote in message
news:4758e$44b2957f$927a2cf9$[email]...

Any links to *non-streaming* video from NASA?


author: mike flugennock

subject: Re: Shuttle SRB videos

text:
Jeff Findley wrote:

The splashdown/post-splashdown POV from the right aft SRB cam is beyond
extremely cool.


author: Pat Flannery

subject: Re: Shuttle SRB videos

text:
[email] wrote:

Those were the Tyvek weather covers on the nose RCS nozzles:
http://images.spaceref.com/news/2006/121.debris.jpg
Remember when the belly used to be black? It's more medium gray now.

Pat


author: Rocky Top

subject: Re: Shuttle SRB videos

text:
<[email]> wrote in message
news:[email]...
The Apollo iconic shots were slow-motion. This runs in real-time
and that moves it down a few notches in quality.


subject: Re: Shuttle SRB videos

text:
On 9 Jul 2006 23:06:58 -0700, [email] wrote:

Two things to be said:

1) Holy. Fracking. Shit.

2) All of the MOV links on spaceflight now go to the NASA homepage,
and not to the movies. YAPAOF - Yet Another PAO Fuckup.

				OM


subject: Re: Shuttle SRB videos

text:
[email] wrote:

Gorgeous footage, to be sure, but comparing it with that staging footage
shot by the aft-pointing camera in the SI interstage, or the tower
camera Saturn liftoff film might be a bit of a stretch. In fact, I've
found the tower camera shots of STS liftoffs to be a bit underwhelming,
perhaps because the camera's not really close enough to create any sense
of drama. There's no poetry or majesty to it; the SRBs light up and bam,
they're outta there. The stills are cool, but the video shot from that
POV just doesn't get it for me.

It was a blast to watch, but, like most events in an STS launch, happens
far too quickly for me to really watch and savor.

God damn, it sure was nice stuff, though; I always knew the Orbiter/ET
were really hauling ass at that point in the launch, but I had no idea
just how much ass was being hauled until I saw that clip from the SRB
cam. Maa-an, they really are wailing, huh?


subject: Re: Shuttle SRB videos

text:
On 10 Jul 2006 08:18:55 -0700, [email] wrote:

...Yes, but does anyone have *working* links to the higher-res
quickslime files?

				OM


subject: Re: Shuttle SRB videos

text:
[email] wrote:

BTW- one of the nozzles on the excess hydrogen burn-off assembly on the
pad broke free and struck one of the orbiter engine bells  before liftoff.
It didn't affect performance during ascent, but they are going to give
it a good going over after landing to see if it is damaged.

Pa


subject: Re: Shuttle SRB videos

text:
On Thu, 13 Jul 2006 03:29:22 -0500, OM wrote:

And thus were the seeds of the "IMAX Bipod
Ramp" tragedy planted...


subject: Re: Shuttle SRB videos

text:
On Mon, 10 Jul 2006 22:50:49 -0400, Scott Hedrick wrote:

(It's time again for the zapkitty's helpful hint
for the day...)

The small ".asx" files of the proprietary M$
bullshit are not real video files, although they
try to pass themselves off as such whenever you
give them the chance. They are just text files
pointing to the actual hiding place on the web
of the files you *really* want.

right_forward_srb_camera.asx

<ASX VERSION="3.0">
 <ENTRY>
  <REF HREF="mms://a1602.v18566d.c18566.g.vm.akamaistream.net/7/1602/18566/v0001/etouchsyst2.download.akamai.com/18355/wm.nasa-global/sts-121/right_forward_srb_camera.wmv" />
 </ENTRY>
</ASX>

Now, several types of web and multinedia apps
are aware of the "mms://" scam protocol and will
fetch the files directly to your hard disk if
you ask them to.

Also, Apple uses a variant of this trick to try
to force streaming of movie trailers with small
faux ".mov" files that are functionally
identical to the ".asx" crap... except that the
text in the ".mov" file is likely to be a
straight http url to the file you want.

But since it's my space agency, thank you, I'll
save folks the trouble... :)

http://whykaykay.nekomimicon.net/

Once I would have ripped the bloated proprietary
wmv files to smaller, more useful, files of
equal quality but my visual acuity is no longer
up to that... *sigh*


subject: Re: Shuttle SRB videos

text:
On Mon, 10 Jul 2006 14:42:59 -0500, Pat Flannery <[email]>
wrote:

...Most people tend to go to gray when they get older, Pat. It's an
aging thing :-P

				OM


subject: Re: Shuttle SRB videos

text:
In article <3bb4c$44b244bf$4366619c$[email]>,
mike flugennock  <[email]> wrote:

The most impressive shuttle launch footage I've seen is from the start of
one of the Imax films -- Destiny In Space, I think.  The camera is so
close to the pad that it's looking *up* at the stack, at a steep angle,
as the engines light.

Alas, it's hard to find poetry and majesty in the shuttle's fairly rapid
takeoff.  Really is a pity that Imax didn't get going in time to shoot
closeup sequences of Saturn V launches...


subject: Re: Shuttle SRB videos

text:
On Mon, 10 Jul 2006 13:58:45 -0500, Pat Flannery <[email]>
wrote:

...You know, these clips actually beg the question(*): Do the SRB
recovery teams place wagers on which one of the pair hits the drink
first?

(*) Shaddap, Mary! :-)

				OM


author: David Stribling

subject: Re: Shuttle SRB videos

text:
Chuck, I am still puzzled how you converted that link to something that
allowed you do download the actual wmv files.  I copied your link below,
changed the "mms" to "http" and pasted in an html file.  When I right click
the link to save the file, the wmv gets changed to "wvx" (I am using IE
which could be the problem ;^) ).  Work arounds to streaming crap fascinates
me and you are da man!


author: Craig Fink

subject: Re: Shuttle SRB videos

text:
On Tue, 11 Jul 2006 06:43:14 +0000, Chuck Stewart wrote:

lol, Thanks for the tutorial ;-)


subject: Re: Shuttle SRB videos

text:
"Chuck Stewart" <[email]> wrote in message
news:[email]...

Thank you kindly. I'll give it a try. Anything over about 20MB I usually
wait until bedtime so it can download overnight.


subject: Re: Shuttle SRB videos

text:
On Tue, 11 Jul 2006 06:43:14 GMT, Chuck Stewart
<[email]> wrote:

...Yeah, they're hidden amongst the "Creme Lemon" hentei videos, but
they're there. Note that I recommend anyone wanting to capture other
streaming video with as little hassle as possible to try SDP -
Streaming Download Project. It works pretty good, although sometimes
you have to parse out the URL manually if the shortcut/link is to a
javascript imbed.

				OM


author: kevin

subject: Re: Shuttle SRB videos

text:
In article <[email]>, [email] says...

True, but it isn't an issue of IMAX hadn't gotten going, so much as not
caring. IMAX was founded in 1967. Commercial films like Tiger Child were
being screened in 1970.


subject: Re: Shuttle SRB videos

text:
On Wed, 19 Jul 2006 20:48:40 -0500, David Stribling wrote:

You weren't quite paying enough attention :)

It's not an http protocol.

It is the mms protocol.

(insert various obscene suggestions for
that acronym)

It's microsoft proprietary crap.

What I meant in the post was that you need
an application that understands the protocol.

In Linux mPlayer and Kaffeine are two
examples. OM mentioned a Windoze app that
does the same: "Streaming Download Project."

(Period concluding entire paragraph should
be included in quotes, right? But what about
my beloved ellipses?... :)

Don't know about Macs.


subject: Re: Shuttle SRB videos

text:
In article <[email]>,
kevin  <[email]> wrote:

I phrased that quite carefully. :-)  Yes, Imax *existed* then, but it took
them a while to wake up to the possibilities of spaceflight films and
start doing something about it.  By the time they did, Saturn launches
were no longer available.  Had they gotten going earlier...


subject: Re: Shuttle SRB videos

text:
On Thu, 20 Jul 2006 13:57:27 GMT, [email] (Henry Spencer)
wrote:

...And after reviewing the thread, I have to rule, once again, *no*
t-shirt for you, Kev :-P

				OM


subject: Re: Shuttle SRB videos

text:
In article <[email]>,
om@all_spammers_WILL_burn_in_hell.com says...

My post wasn't a tee-shirt attempt. I know the rules, and IMAX is off-
topic for tee-shirts.

I was trying to clarify just what "getting started" meant.


subject: Re: Shuttle SRB videos

text:
On Fri, 21 Jul 2006 19:48:52 -0400, kevin
<[email]> wrote:

...Depends on who's stuffed in the shirt.

				OM


author: Kevin Willoughby

subject: Re: Shuttle SRB videos

text:
In article <[email]>,
om@all_spammers_WILL_burn_in_hell.com says...

IMAX is a "flat" system. Sure you're not thinking of Cinerama, with is
deeply curved screen with a thousand peek-a-boo slits?


author: Bonnie

subject: Bearding Question!

text:
I have 4 hives that are doing well,but one has 2 hive bodies and a super on.
It has a screened bottom board also. Anyway so do all the others,but this
one hive ,the bees are always on the outside front in clumps! Even after
dark! At first I thought it was because it was really hot, but now its
cooler and they're still doing it! By morning they're gone in the hive.
Sometimes they just start working and never go in! I thought maybe it was
full but we checked and the super has lots of room yet and they upper hive
body is almost full but not quite! Any thoughts as to why they are hanging
outside?

Thanks ,Bonnie


author: [redacted]

subject: Re: Bearding Question!

text:
Pull a super back about 3/4"
This makes an entrance above the brood nest, eases congestion and
provides ventillation.
Because of the way the rabbett is cut the back is still sealed and the
front is open.
Remember bees need a lot of surface area to dry honey so an extra super
or two of drawn comb hurts nothing and the bees will keep it free of
pests.
Toss a queen box  or 3/4" scrap block between the covers to provide
some airflow out the top.
.


subject: Re: Bearding Question!

text:
Hi Bonnie,

I have had this happen to a hive of mine as well. The first time I saw
it I thought that I might be seeing the beginning of a swarm... I was
pretty nervous about it. I have been told that this can be a "normal"
activity that the bees are performing. If you watch them closely, you
may see them fanning their wings. They do this for 2 reasons. One is to
cool down the hive. They need to maintain 93 degrees for the Queen to
lay eggs and all activities to run properly. Second, they may be
fanning to help ventilate the hive. As you know, nectar has a high
percentage of water in it. In order to make honey from the nectar, the
bees have to evaporate a lot of water. By fanning, they are creating
air currents that drift up through the hive to help care away excess
moisture. I suspect that this may be the case since this is the high
nectar flow time of year (results may vary in your area). I have tried
to help my bees by slightly lifting one side of the telescoping top
cover and placing a 1/2" piece of wood under it. This allows more air
to flow up through the hive while the cover still hangs over the entire
box enough to protect the bees from the weather and robbers.

You will still want to perform regular inspections as this is also the
time of year for swarming.

Also, keep an eye out on the honey supers. When the bees have drawn and
filled 8-9 frames and are working on the filling the last 2, be ready
to add another super. I have allowed a hive to completely fill and cap
2 supers all the way to the edges before I opened up the hive and took
off the frames to extract and give back. Man, did those bees get UGLY.
They are content to work and let you inspect them until they are
running out of space to store honey. Then they get mad.

Hope this helps,
Paul Bilodeau


subject: Re: Bearding Question!

text:
Thanks for the reply! It does help! We checked the hive yesterday and they
seem to be doing well! Now today they aren't outside as bad as before!
Thanks again!

Bonnie


author: Gerhard Fuernkranz

subject: I painted my room - color appearance

text:
Recently I've painted one of my rooms.
When illuminated with daylight the wall has a beautiful light
apricot color. But in the night with tungsten illumination, the
color appears to be rather pink and no longer the beautiful apricot.

Now I am wondering, why the chromatic adaption of my eyes
does not work? Basically I had expected, that my eyes would
adapt to the different illumination and the subjective appearance
of the color would remain the same. But it does NOT.
And it can't be a problem of _MY_ eyes - other people also
told me, that their impression is the same and that the
room looks rather pink at night.

Is there anything wrong with my understanding of
chromatic adaption?

BTW this also raised another question for me:

Assume I have two different Dyes, which reflect the same CIE
color if they are illuminated with D50. But they are chemically
different and achieve this equal CIE colors with different spectral
distributions of their reflectancies.

Now I'm wonderig what happens, if I change the illumination
to e.g. a tungsten lamp? Will the two Dyes now still appear to
have the same color or is it possible that - with a different
illumination - there may be now a noticable color difference
between the two objects?

If the answer is "yes", then I am wondering how relative colorimetry,
ICC profiles and whitepoint adaption to a different light source
can work at all (if only the CIE colors of the object and the
light sources, but not their spectral distributions are considered).

Thanks,
Gerhard


author: tlianza

subject: Re: I painted my room - color appearance

text:
Hello Gerhard
Well in short....Yes and No

Leonardo DaVinci was one of the first researchers of his time to recognize
that the "Color of an object takes on the hue of the object which
illuminates it".  Regardless of "adaptation" as it were, the PHYSICAL color
of the object is different.

The chromatic adaptation that you refer to is more wishful thinking than
science.  The concept that we somehow adapt to the brightest luminance in
the scene and then it "magically" becomes the reference white is not correct
in any way.  I can demonstrate this in the laboratory by setting three
monitors to different white points and then adjusting them to equal
luminance. They don't appear to be the same brightness, nor do they appear
to be white.  The lower color temperature display shifts towards the red,
and the higher temperature shifts towards the blue. The middle display also
has a hue.  One might attribute this to "incomplete adaptation" or one might
say "hey, the colors are different, why should any of them look white?" .

You have just defined a metameric pair: two colors that appear to be the
same color visually under one illuminant and different under a second
different illuminant.  That is why we specify the conditions of comparison
when we look at inter media comparisons.

The process doesn't work correctly and that is a very weak point in the
architecture that has been known from the day it was proposed. Adaptation
and Metermeric differences are taken into account in the profile generation
process. The fact that different assumptions can be used for input, display
and output lead to interoperability problems when profiles are supplied by
multiple vendors.


text:
Gerhard:

In article <R3JS6.21435$[email]>,
tlianza <[email]> wrote:

	Actually, the answer to you question it an unqualified yes.

Unfortunately, your statements seem to assume that chromatic adaptation/
a color appearance model will compensate for a change in viewing
illuminant. This is a fairly common error made by a lot of color scientists.
Tom also seems to assume this in his last few posts on this newsgroup.

I will try and clarify. Hopefully, what I say will help or someone more
familiar with this common error will jump in the discussion with a more
suitable description. I will try and use "color" to imply the visual
appearance and colorimetry to imply the measured color (such as CIEXYZ).

The observation that "colors" of objects remain LARGELY unchanged under
different illumination is referred to as "color constancy". The fact that
they do not remain absolutely unchanged is sometimes referred to as a
failure of "color constancy" (though I cannot see how something that is
defined as an observed phenomenon can ever fail particularly when the
"largely" is used in the definition).

Note however that chromatic adaptation or a color appearance model does
not compensate for a change in viewing illuminant. Clearly metameric pairs
that are metameric under one illuminant and not under another illustrate that
adaptation cannot compensate for changes in the viewing illumination. This
is also not the intended purpose of adaptation transforms or color appearance
models that incorporate these tranforms.

The intended purpose of a color appearance model is to let you determine
what colorimetry produces a given appearance under a set of viewing conditions
different from the original viewing conditions. So if you are given
a set of reference "viewing conditions", the colorimetry of a "color"
under those reference viewing conditions, and a different set of viewing
conditions; an appearance model is intended to let you determine what
colorimetry under the new viewing conditions will produce the same
"visual appearance" as the original colorimetry under the original viewing
conditions. That is a lot of verbiage but I cannot put it more clearly in
spite of having tried. One more way to convince you is by noting that
in the above statement we are allowing the (reflectance) stimulus to be changed
to match visual appearance, whereas in the case of the same object viewed
under multiple illuminants we are preserving the stimulus - clearly different
cases. That said, the phenomenon of color constancy can be often explained
by the adaptation mechanisms: if you think about it, if the objects visual
appearance remains unchanged under different illumimants a good color
appearance model should predict the correct colorimetry for it under a
different illuminant from the one under which it is recorded. However, if
the object appearance changes under different illuminants (which is the
case for metameric pairs) the color appearance model cannot be used to
predict colorimetry for it under a different illuminant.

	I agree. What you have is a metameric pair.

Sorry, but I must strongly object here. The procedure is not intended for
this! This should be clear from the discussion above. Again the problem is
not with the tool in this case but with the tool being applied to a job
that it was not intended for in the first case. "Know thy tools" is a maxim
that comes to mind. Current color appearance models have enough shortcomings
to be criticized on but this is clearly not one of them !

	Hope that helps clear up some of the confusion.

-Gaurav Sharma


text:
Hi Gaurav
scientists.

I'm not sure that I understand the "chromatic adaptation/" notation.  What
were you trying to say?

I'm not sure what common error I made....
Gerhard said the wall changed color when the illuminant changed.  I
understood HIM to believe that the adaptation properties of the eye should
compensate for that.  I pointed out to him that the color of the wall
appeared different because IT WAS DIFFERENT.  It has nothing to do with
"adaptation" .  I went on to point out that many common methods of
"adaptation"  don't work well.  For instance, the basic division of the
TriChromatic coordinates of a color by the reference white is often referred
to by some researchers as "adaptation".  One even called that Von Kreis
adaptation..... he (Von Kreis )must be rolling over in his grave... I think
we can both agree that these operations have nothing to do with "Adaptation"
per se.

I believe that the "/"  in the first sentence might mean "or".  Later on you
say

That has been the major point of all my prior posts .  That is why I have
said repeatedly that we need to apply the same illuminant to the measured
spectral data as we use to view the copy. There are two reasons: Metameric
failure and defects in appearance modeling. My earlier points (rants)
concerning appearance models and their application to profiles had nothing
to do with the efficacy of the appearance model (which is often
questionable).  It had to do with the lack of a mechanism to communicate the
fact that an appearance model had been used in the profile and what
assumptions where made in the model.  This is especially frustrating when
applied to the Profile Connection Space in the ICC profile model, because
there is no specification of adapting luminance.  I hope that you would
agree that if the input adaptation model made a different assumption about
adapting luminance, than the output, the results of the appearance model
probably wouldn't be satisfying.

The concept of Color Constancy is a hoot.  It's similar to the reciprocity
law in photography: How can law be noted more for it's failure than success:
i.e. Reciprocity Law Failure.  Another odd notion is that of "Unwanted
Absorptions" of dyes.  We should call them "Inconvenient Absorptions".


text:
Hi Tom:

	As I indicated earlier, I'm not sure if I can phrase this any
clearer and would welcome any comments from other folks who can express
the idea more clearly than me. I've inserted some comments below.

The real point is that
chromatic adaptation (or more generally a color appearance model) is NOT
intended for use in predicting the "color appearance" of a single
reflectance function (i.e. a physical object such as the paint in Gerhard's
room) when the viewing illuminant is changed. Trying to use it for that purpose
and encountering problems is not a failure of the model but a failure to
understand where the model is applicable. I am including below the
part from my last posting that emphasized this point in the >*****<
demarcated region.

	In Gerhard's case, for instance, a color appearance model will
let him determine what paint to use under the incandescent lighting to have
have the same visual appearance as his original paint under the original
lighting. But the color appearance model (or chromatic adaptation) does
not say that the visual appearance of his original paint remains unchanged
when he goes to incandescent lighting.

... Stuff deleted....

	I don't fully agree with you here. If your intended goal is
reproduction of an original that is going to be compared with the original
side by side, yes what you say is correct. In a lot of cases however
the reproduction is not viewed side by side as the original and under
different viewing conditions from the original. The desirable goal in this
case, is to produce a "copy" that preserves the "visual appearance" of the
original. To do this, you want to apply to the original the illuminant under
which the original is viewed, transform the data to the colorimetry required
under the illuminant (and if necessary other viewing condition parameters)
to be used for viewing the "copy" and reproduce that colorimetry in the
copy. Color appearance models are intended for use only in the second
case and not in the first.

	I'm fully with you with regard to the limitations of existing
appearance models and the interoperability problems.

	Once again a statement in characteristic Tom Lianza style :)! I
agree with you and in part share some similar concerns, but take a far
more tolerant view. We inherit a lot of terminology, which even if
inappropriate/incorrect is hard to eliminate at short notice. I think
all statistical observations tend to have exceptions but are useful
nonetheless. That is why I used the definition below:
The illuminants for which color constancy "fails" [to continue to contribute
to the misuse of the term :) ] "severely" are man-made ones and one common
belief is that "adaptation" in the visual system evolved so as to provide
a survival advantage - it is potentially beneficial to recognize predators
as having the same color appearance irrespective of the phase of daylight.
I also think that there is some value (particularly pedagogical) to talking
about ideal behavior - the notion of unrealizable "ideals" goes
back to the times of the ancient "Greeks".

cheers,

-Gaurav


author: Artemus

subject: Re: Am I missing something???

text:
"Ignoramus31358" <[email]> wrote in message
news:[email]...

That it is being sold as furniture?
Art


author: Tim Wescott

subject: Re: Am I missing something???

text:
On 02/07/2011 11:24 AM, Ignoramus31358 wrote:

The chance to sell some "found art" for big bucks?  There's some parable
about the collapse of western civilization buried in there, somehow.


author: DoN. Nichols

subject: Re: Am I missing something???

text:
On 2011-02-07, Ignoramus31358 <[email]> wrote:

	I think that he is presenting it as an example of "found art",
not as a welding mask to be used.  Note that he also has a link to an
art gallery.  He would probably be insulted if someone bought it to
weld with. :-)

	"deep distressed green with nice rivet details" certainly does
not sound like a description aimed at someone who intended to *use* it.
It may even be permanently attached to the rod shown under it as a
stand.

	Enjoy,
		DoN.


author: Edward Hennessey

subject: Re: Am I missing something???

text:
"Ignoramus31358" <[email]> wrote in
message news:[email]...

My guess is he's hoping P.T. Barnum is right.
It shows some rough similarity with the famous scifi robot
Gort in "The Day the Earth Stood Still".

There are many mask collectors who go beyond the
ethnographic examples seen in Anthropological museums.
Add to that the "cosplay "(costume play) crowd and the
current fascination for "steampunk art" (try Google images)
and you have an inventory of some of the avenues he might
hope are productive.

Personally, it looks like a regular, tired welding helmet to me. If it
showed the chance artistic alterations that might occur if it were
dredged out of a Superfund sludge pit or mine leach pond,
then it might have more tingles. As it is, best of luck, most
of the time.

To that yawning appreciation, I will add that this: the daring
(read "nutty") price may be a positive for him. If you ever
look at comparitive book prices for the same title, same
makeup, same condition on, say, www.bookfinder.com ,
you will often find a spread of prices topped by some
outrageously high outlier. Occasionally, someone will spring
for the exorbitant volume merely on the theory that the
stratospheric price_must_ mean it is better than others
similarly described. Usually, Mr. Exclusive's Rarities orders the book
drop shipped from a competitor lower down on the bookstore
list. The seller doesn't have the book, he just lists it and
rakes in  the money. Barnum bunkum at its best.

Regards,

Edward Hennessey


subject: Re: Am I missing something???

text:
On 2011-02-08, Edward  Hennessey <[email]> wrote:

Well, if you have a super old riveted mask, I would be interested!

Ed, I would really like to retire, and when I do so, I would really
like to make some steampunk art.

i


author: Snag

subject: Re: Am I missing something???

text:
Artemus wrote:

I think they're trying to call it art ...Art .


subject: Re: Am I missing something???

text:
On 2011-02-08, Edward  Hennessey <[email]> wrote:

Ed, the only plus of this mask that I see, is that it is riveted and
represents steampunk style. I may pay $3 for it at a garage sale, as
opposed to my customary $1.

i


subject: Re: Am I missing something???

text:
"Ignoramus908" <[email]> wrote in message
news:[email]...

I##:

Parting the steaming mists and staring into  the blown-glass orb
mounted in the bronze and silver sconce ornamented with chrome
doodads in front of me, I see you will be successfull, make
millions, kopeks, money even.

When you are famous and beyond rich, we will all be
proud to say we knew you when...and always enjoyed
free lunch at your studio.

Regards,

Edward Hennessey
I


subject: Re: Am I missing something???

text:
"Ignoramus908" <[email]> wrote in message
news:[email]...

I:

First, let me ask a simple question. You are Ignoramus0-nth power?

Next, I called and the vintage welding helmets are'nt riveted. By
happenstance,
I also had a conversation with a friend who does eBay. They got back
to me
and said you are not looking for an item they see everyday. Was this
something
of familiar notice to you way, way back East?

But if you do have a lot of  surplus but nifty hardware around the
shop you
may want to jump on steampunk architecture:

http://www.scoutingny.com/?p=3534

Great signage that isn't subject to signage regulation. I like it.

Regards,

Edward Hennessey


author: Dennis

subject: Re: Am I missing something???

text:
"Snag" <[email]> wrote in message
news:bsY3p.85106$[email]...

ya beat me to it!


subject: Re: Am I missing something???

text:
"Ignoramus5310" <[email]> wrote in message
news:[email]...

I31358:

You and me both, plus I've got a few to sell you.
And I'll throw in the matching bolts in my neck if you take all
the helmets...no stand included for them though. It's kinda
attached at the shoulders.

If you haven't Google imaged "steampunk art" and skimmed
a few of the better websites, the higher level of that stuff
can be very amusing. It's all based around something like fusing
the Victorian Period and futurististic mechanisms. If you're
looking for a zippy ray gun mockup, there's no background
check.

Regards,

Edward Hennessey


author: Kenshin

subject: exp(-x) = x-1

text:
Howdi,

' Show that exp(-x) = x-1 has one real solution and solve the x of the
form of the infinite series. '

The first part of the problem is really simple just by using the
differentiation, but any idea for the second part?


author: rancid moth

subject: Re: exp(-x) = x-1

text:
On Sun, 07 Feb 2010 22:03:20 -0800, Kenshin wrote:

Use the Lagrange inversion theorem...and do it from scratch.


author: Dave L. Renfro

subject: Re: exp(-x) = x-1

text:
Kenshin wrote:

I think the standard way that one used to do something like
this (the power series part) is to use something called
"reversion of series", which can be found in most really
old calculus and algebra books (before 1900, and thus freely
available in google's book archive). As for the present time,
I guess this would depend on what level of math we're allowed
to use (which you didn't say) or what computing devices are
allowed (calculators? computer algebra system calculators?
MAPLE or Mathematica type programs? . . .)

Dave L. Renfro


author: Torsten Hennig

subject: Re: exp(-x) = x-1

text:
http://de.wikipedia.org/wiki/Lambertsche_W-Funktion

Best wishes
Torsten.


subject: Re: exp(-x) = x-1

text:
On 2월8일, 오후4시42분, Torsten Hennig <[email]>
wrote:

Got it. But the problem's demand is the form of 'infinite sum'.

Can we express Lambert's W-function into the form of the infinite
sum?? or any other ideas????


subject: Re: exp(-x) = x-1

text:
On 2월8일, 오후6시31분, Torsten Hennig <[email]>
wrote:

Thank you very much and you're right.

The site says that the Taylor series of LWF around 0 (called TW(x))
has the radius of convergence of 1/e, and I think we must have W(1/e)
with this problem. ( (x-1)exp(x-1) = 1/e )

Maybe TW(1/e) is convergent... but how???


subject: Re: exp(-x) = x-1

text:
The solution x0 to your equation in terms of Lambert's
W-function is given by
x0 = 1+W(1/e)
(look for 'generalizations' under
http://en.wikipedia.org/wiki/Lambert_W_function
)
Now insert into the Taylor series of Lambert's
W-function (which is also part of this web-page).

Best wishes
Torsten.


subject: Re: exp(-x) = x-1

text:
1. Which criterion is usually used to show
the convergence of an alternating series
sum_i (-1)^i a_i ?
2. Which theorem ensures that
W(1/e) = lim (x-> 1/e) sum_i (-1)^i a_i*x^i =
sum_i (-1)^i a_i * (1/e)^i ?

Best wishes
Torsten.

s


subject: Re: exp(-x) = x-1

text:
On 2월8일, 오후8시59분, Torsten Hennig <[email]>
wrote:

Thank you... my too much term of non-math lol


author: Kuusama Juha,,,VTT

subject: Why circuit boards are green?

text:
Not that the question is anything important, but I am still curious:
Why is that almost all printed circuit boards are green? I have seen
a few blue ones, but no red, yellow, company logo etc. Is there a
technical reason or could it be that the marketing "geniuses" have
not tought about it (yet)?


author: Dale Ulan

subject: Re: Why circuit boards are green?

text:
[email] (Kuusama Juha,,,VTT,) writes:

The green layer is a solder-mask, and is used to make a finished board
look neat, and to avoid solder bridges, especially when using wave
soldering (or any other mechanized approach). I've seen red mask,
but most that I've seen are green.

A bakelite board will look brown in colour, and, if the solder mask
is put on, looks like a brown board with green 'paint' on either side
(or just one side) of the board.
A fibreglass board will look green from the side, because the green
solder-mask makes the board appear that colour. If you got a fibreglass
board with no mask, it would be a whitish-grey colour.
Teflon boards do exist, as well... but I'm not sure about that one.

I'd guess the stuff they invented for solder mask was green, so they're
not about to change. Also, any change in any chemical probably requires
a better than normal cleaning of the machines that make boards. A lot
of companies do not make their own boards... they ship them to a real
boardhouse.


author: TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus

subject: Re: Why circuit boards are green?

text:
In article <[email]>, [email] (Kuusama Juha,,,VTT,) writes:
The color of the board shows the composition of it, hence the use of it.

Original and older boards were bakelite composition, and were brown.
Phenolic (spelling) was a tan
Most "non filled" fiberglass boards used in computers are green.
Filled fiberglass is blue.
Teflon is white.

As boards evolved more and more demands were made of them.  First boards were
used mainly in audio circuitry.  Couldn't be used in high voltage or RF because
it would arc and burn.  Most boards today are fiberglass, the type being chosen
by its use and cost.

Boards in satellite and microwave communication are teflon (and ceramic) as the
fiberglass, and other boards are conductive (they actually work more as a
capacitive dialectric, but the word conductive simplifies explaination) at the
high frequencies.

Another printed circuit material used mainly in automotive and interconnections
is a thin flexible (mostly mylar) material and is used to connect the front of
the vehicle (etc) to the back instead of wiring harnesses.  Camcorders use this
to intereconnect the boards inside where wires would be a nuisance.

Am working on a generator made by Hewlet Packard right now and the entire board
is gold plated, boy it looks expensive!!!

Hope I got most of my facts right as I am working from memory of material read.

My education was pre-transister!


author: Brian Sassone

subject: Re: Why circuit boards are green?

text:
In article <[email]> [email] (Dale Ulan) writes:

I've used clear solder mask before - it allows you to see contrast between
copper and etch.  This particular vendor used a very dark (almost black)
FR4, so they looked pretty cool, too.  There was no cost difference and they
didn't even blink when I requested it.  I think they also had red and
yellow.  (I wanted to use dayglo colors or do graphics prints... :)

I've seen red - which is actually more pink or rose than red - and was told
that the Next used all black circuit boards.  Talk about design details!

It's very useful for prototyping to have different revs of the board
different colors - you can tell immediately what you're working on.

-Brian


author: Bill Mayhew

subject: Re: Why circuit boards are green?

text:
Fiberglass boards are available in several colors.  Sitting right
here, I have unetched board stock that is white, blue, green and
yellow respectively.  I've also seen black boards.

Solder mask is available in a variety of colors too.  Depending on
the supplier, the color helps indentify the material.

Don't forget conformal coating.

I don't think I've seen phenolic impregnated paper boards in
anything other than the familar brown, but it would not be
difficult to add a dye to change the color.


author: John Nagle

subject: Re: Why circuit boards are green?

text:
[email] (Dale Ulan) writes:

       It's possible to make boards in other colors, and I have an ad
for laser light-show equipment which offers the circuit boards in your
choice of Day-Glo (tm) colors.

       The usual light green color is just the natural color of Fiberglas.
The dark green or blue is the solder mask layer, and I suspect that color
is a dye.

						John Nagle


author: Michael Daniel Fennell

subject: Re: Why circuit boards are green?

text:
Why are circuit boards green?  The material used to make them goes by two
names.  If it is used to make circuit boards it is called FR-4.  The same
material is used in the cryogenics industrya and marine industries as a
structural material and is called G-10.  FR-4 and G-10 are both green.  They
are not green because of a solder masking agent.  The basic ingredients are
a clear epoxy resin and glass fibers.  I am not sure what the specs are on
the resin, but if you are really curious you can call NEMA (National
Electronics Manufacturing Association) or Ciba Geigy (a major manufacturer
of epoxy resins) to find out.  As an aside, I occasionally mix clear epoxy
and glass microsphres to cast small structures for cryogenics experiments.
The proportions of glass to epoxy are about the same as in G-10.  They are
the same green color.


author: Geoff Swan

subject: Re: Why circuit boards are green?

text:
In article <[email]>, [email] (TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus) writes:

Rubbish. The reason for the colour of the boards depends on the solder
mask that is used. Older boards (bakelite and phenolic) rarely used
a solder mask (these boards are not suited well to automatic stuffing
and soldering techniques) and hence are the colour of the compound
used to make them. These days boards are made of fibreglass for most
general purpose uses and have a solder mask applied to them to prevent
close traces shorting to one another during soldering (and also to prevent
the decomposition of traces under harsh environments). The light and dark
green boards ofter seen have a "dry film" mask applied to them (usually
applied as a complete film photographically produced). The blue (and red
or orange) boards are a two-part epoxy or a liquid-imageable resist
formulation and are applied in a different manner. There's a lot of info
about the pro's and con's of each, but that's another story...

    Sla/n go fo/ill,
                    Risky B.
--------------------------------------------------------------------------
Geoff Swan (research & development)   _--_|\         [email]
Megadata Pty Ltd                     /      \
2/37 Waterloo Rd, North Ryde,        \_.--._/               +61 2 805 0899
NSW 2113, Australia.                       v          (Fax) +61 2 887 4847


subject: Re: Why circuit boards are green?

text:
In article <[email]>, [email] (Geoff Swan) writes:

Sorry Geoff,

Agree solder mask is green, but in the old days we didn't have wave soldering
machines (which are another topic again).  I had a crew of a dozen ladies which
could stuff and hand solder a board like lightning!

Board under the mask was the original query.

BTW cheap inport electronic devices (mainly from 3rd world countries) are done
with brown pheonolic boards.  Is seems the electronics industry has discovered
the cheap labor pools.  Workers are paid by the board to assemble circuits at
home.  They are very obviously hand soldered.  Quite a few tape recorders are
being brought into Canada from Red China.  In China there is no warranty for
the equipment other than if you plug it in and it works it's yours.  One of my
co-workers spent a year there and he said the failure rate out of the box was
almost 50%.

Also, the original method for making printed with conductive ink on a regular
printing press.  An old lithographer friend had a press for this.  After the
etching method was developed he used the press to print wood grain on doors.


author: Jan Drew

subject:
Re: Woman Disabled by THIS YEARS FLU SHOT 10 days AFTER vaccination
	...

text:
On Jun 1, 10:21�pm, Bob Officer <boboffic...@127.0.0.7> wrote:

NO.

Posting lies and samp

http://www.skeptics.com.au/shop/


author: Mark Probert

text:
On Jun 1, 10:05 pm, Jan Drew <[email]> wrote:

No video available. There are only comments.


author: Peter B.

subject: Re: Woman Disabled by THIS YEARS FLU SHOT 10 days AFTER vaccination ...

text:
"Jan Drew" <[email]> wrote in message
news:[email]...
On Jun 1, 10:21?pm, Bob Officer <boboffic...@127.0.0.7> wrote:

NO.
=====================================
Then prove it dragon breath.


author: Paul von Hippel -- Ohio State

subject: categorizing continuous variable

text:
I'm seeking references for the common advice against categorizing
continuous regressors. In particular, I'm interested in advice
against the common practice of breaking a continuous regressor
into quintiles.

When a regressor is broken into quintiles, the quintiles are likely
to have a nonlinear relationship with the outcome, even if the original
regressor does not. I've noticed this artifact in published research,
and am curious whether it has been remarked in the literature.

Many thanks,
Paul von Hippel


author: Rich Ulrich

subject: Re: categorizing continuous variable

text:
On Thu, 10 Jul 2003 09:15:36 -0700, Paul von Hippel -- Ohio State
<[email]> wrote:

 - that would be for the same reason that ranks give artifacts.
You expect that for any complicated analysis.
It is easiest to illustrate in an example generated with
a high r-squared.

If you start with a plot of  'normal'  versus 'normal'  and do
a rank-transform to one, , the ranks will spread apart the
scores in the middle and collapse the scores at the extreme.
Yes, the new plot is not a straight line.

I don't remember ever seeing a great amount of detail on
the artifact with Ranks, but I would look for literature about
Ranks instead of  Quantiles.


author: [redacted]

subject: Re: categorizing continuous variable

text:
Paul von Hippel -- Ohio State <[email]> wrote:
: I'm seeking references for the common advice against categorizing
: continuous regressors. In particular, I'm interested in advice
: against the common practice of breaking a continuous regressor
: into quintiles.

: When a regressor is broken into quintiles, the quintiles are likely
: to have a nonlinear relationship with the outcome, even if the original
: regressor does not. I've noticed this artifact in published research,
: and am curious whether it has been remarked in the literature.

: Many thanks,
: Paul von Hippel

There's a literature extending back at least to the 1940 when Peters and
van Voorhis showed the problem created by dichotomizing a variable at the
mean.  The most recent one that I like summarizes the issues quite nicely:

MacCallum, R.C., Zhang, S., Preacher, K.J., & Rucker, D.D. (2002). On the
practice of dichotomization of quantitative variables. Psychological
Methods, 7, 19-40.

Mike Babyak


author: brian a m stuckless

subject: Magnitudes ..SI kilogram mass.

text:
$$                Eric [the ReTARDant] Gisse wrote:

$$            GR dummys BOTCH their "EQUiVALENCE" test.
$$   GRists REFUSED to use DiFFERENT test-masses (m_1 & m2), in
$$   BOTH experiments. And, HAD the Cracked-pots used DiFFERENT
$$   "actual physical" test-masses ..in BOTH experiments, those
$$   dimwits MAY HAVE REALiZED that, for EQUAL forces (F_1=F_2)
$$    ..acceleration a_2 is iNDEPENDENT of *MAGNiTUDE*-of-mass.
$$                             -=-
Since acceleration a_1 isN'T iNDEPENDENT of *MAGNiTUDE*-of-mass,
$$                        < snicker >.
Re: Magnitudes ..SI kilogram mass. My CAPiTALiZATiON & brackets.


author: Randjrang

subject: ALBANY LYME HEARINGS

text:
OK.  I went to the hearings.  I brought my family I listened. I learned a few
things.  I fell asleep a few times.  NOW WHAT??????????????????????????

I thought it went well.  The committee seemed well informed and up to date on
the current situation on lyme.  The speakers were good also.  Now what....is
there something else I am supposed to do?????

I would also like to know the following:

Was the turnout what was expected??   How many people usually show up for
hearing such as these.  Did the people there have any impact on the committee??

What exactly is the desired result of these hearings.  Is it legislation???
similair to the COnn. legislation, or something else.

I am sorry if I am asking dumb questions but I was hoping to see some input
from the people who post on here.  I haven't really seen much and I know
eveyone is probably exhausted but I am still curious.  Any information would be
greatly appreciated.  I was the one with the lyme sweatshirt with the big green
ribbon on it, in case anyone wants to know.

Mary - NY


author: Ellen Lubarsky

subject: Re: ALBANY LYME HEARINGS

text:
Hi Mary,
Please give us a little recuperation time here, and then I promise I
will post on what comes next here in NYS.   I think the turnout was
excellent.  I think it did have an impact on the committee.

Thanks to you and everyone else for attending   Just bear with me until
I can think again and I will get back with some information.
Ellen


subject: Re: ALBANY LYME HEARINGS

text:
Ellen:

Please have Monica and Joel Miller contact me. 631-581-8123.  Thanks

Lynn Tewksbury


author: John Clark

subject: Re: Retaining the Null Hypothesis

text:
Cognitee wrote:

I am at a total lost here. How do you measure 'reliability',
or define a standard of validation in quantiative terms without
appeal to some form of statistical reasoning.

Of course it could be that if the results are trival, one can
make trival statements as to 'apparent likeness' based on qualitative
comparisons.


author: ZAZU

subject: Newbie Question

text:
I'm New at this 70o wu's.  Can someone point me to a setique setup page that
points to where setique should be pointed to Get wu's.  IP? or
?.berkeley.edu??


author: Chris

subject: Re: Newbie Question

text:
Hi

http://www.geocities.com/lwdthesatanofseti/setiqueue/setiq_howto.html

"ZAZU" <[email]> wrote in message
news:G8ev8.3886$[email]...
that


subject: Re: Newbie Question

text:
Setiqueue will get WU when a client connects to it,
See the setup page, I used it and had no problems :)
Chris

"ZAZU" <[email]> wrote in message
news:G8ev8.3886$[email]...
that


subject: Re: Galaxies without dark matter halos?

text:
greywolf42 <[email]> wrote in message news:...

{snip}

I just ran across a paper that measures both stellar motions and gas motions
in the galactic center.  It is "Stellar Velocities and the Mass Distribution
in the Galactic Center,"  GH Rieke and MJ Rieke, July 1, 1988, APJ,
330:L33-L37

54 individual star motions were determined in this and contained referenced
papers.  The motion of same was compared to the motions of gas around
Sagittarius A*.  Final conclusion is that the motion of the stars is
"formally inconsistent" with the "dominant central-mass model" (i.e. black
hole) used to explain the motion of the gas.

The Rieke's note: "... the gas in the galactic center may be subject to
non-gravitational forces leading to high velocities, in which case the mass
in the region will be overestimated ..."

Which bears directly on this thread.

The paper is dated 1988.  Does anyone know of any followup papers?

greywolf42
ubi dubium ibi libertas


author: Steve Willner

subject: Re: Galaxies without dark matter halos?

text:
In article <[email]>,
 greywolf42 <[email]> writes:
....

The easiest way to find followup papers is to do a citation search in
the ADS.  Alternatively, you can use the "find similar abstracts"
function, ask for the query form instead of query result, put in a
date limit (1988 or later in this case), and then submit the query.

As Phillip Helbig says, you will find no shortage of papers.  (Andrea
Gehz's UCLA group is worth mentioning in addition to Genzel's.)


author: Joseph Lazio

subject: Re: Galaxies without dark matter halos?

text:
(Slowly getting back to things ....)

g> I just ran across a paper that measures both stellar motions and
g> gas motions in the galactic center.  It is "Stellar Velocities and
g> the Mass Distribution in the Galactic Center," GH Rieke and MJ
g> Rieke, July 1, 1988, APJ, 330: L33-L37

g> 54 individual star motions were determined in this and contained
g> referenced papers.  The motion of same was compared to the motions
g> of gas around Sagittarius A*.  Final conclusion is that the motion
g> of the stars is "formally inconsistent" with the "dominant
g> central-mass model" (i.e. black hole) used to explain the motion of
g> the gas.

g> The Rieke's note: "... the gas in the galactic center may be
g> subject to non-gravitational forces leading to high velocities, in
g> which case the mass in the region will be overestimated ..."

g> Which bears directly on this thread.

g> The paper is dated 1988.  Does anyone know of any followup papers?

I've already posted in sci.astro a list of authors to consult.  Off
the top of my head, Sellgren, Genzel, Ghez, Goss, and Roberts come to
mind.  For instance, Roberts, Yusef-Zadeh, & Goss (1996) find that the
ionized gas in Sgr A West implies a central mass of 3.5E6 solar
masses, fairly close to what the current stellar data suggest.  Also,
Genzel has published multiple papers showing the mass estimates given
by different kinds of measurements (gas vs. stars).


subject: Re: Galaxies without dark matter halos?

text:
[Mod. note: I'm restricting this post to s.a.r. only, as it seems
we're wandering off-topic for s.p.r. in this sub-thread -- mjh]

Joseph Lazio <[email]> wrote in message
news:[email]...

And as I've noted several times before, anyone can post a list of authors.
But your list (posted several times now for different purposes), is not
necessarily relevant.  And a list of *authors* is certainly not relevant
when the request was for references to *papers*.  The question was whether
anyone knew of a DIRECT followup to Rieke's 1988 paper.

greywolf42
ubi dubium ibi libertas


author: Phillip Helbig---remove CLOTHES to reply

subject: Re: Galaxies without dark matter halos?

text:
In article <[email]>, greywolf42
<[email]> writes:

                      ^^^^

                          ^^^^

Research into the kinematics and dynamics of the galactic centre has
made ENORMOUS progress since 1988.  Quite frankly, I can't see how an
observational paper from 1988 is even worth looking into if one wants to
understand what is going on at the galactic centre.

In particular, Genzel and colleagues have done some truly excellent work
in this area.  If their conclusions contradict those of the 1988 paper,
don't believe the 1988 paper.

Specific papers:

   http://www.arxiv.org/abs/astro-ph/0306214

   http://www.arxiv.org/abs/astro-ph/0210426

   http://www.arxiv.org/abs/astro-ph/0201031


author: Jonathan Thornburg

subject: Re: Galaxies without dark matter halos?

text:
In article <[email]>,
Phillip Helbig---remove CLOTHES to reply <[email]> wrote:
[[observations of matter motion close to the center of the Milky Way]]

Another reference (a bit less technical):

@article{
	PhysicsToday-Feb2003-BH-news,
	title = "Infrared Adapti8ve Optics Reveals Stars Orbiting
		 Within Light-Hours of the Miliy Way's Center",
	subtitle = "Orbital periods as short as 15 years clinch the case
		    sfor a supermassive black hole at the Galaxy's heart",
	author = "Bertran Schwarzschild",
	journal = "Physics Today",
	year = 2003, month = "February",
	volume = 56, number = 2,
	pages = "19--21",
	}

This is probably online somewhere at http://www.physicstoday.org,
but you may need to be a Physics Today subscriber to see it.

ciao,


subject: Re: Galaxies without dark matter halos?

text:
Phillip Helbig---remove CLOTHES to reply <[email]>
wrote in message news:[email]...

LOL!  We don't get to pick and choose our data, in science.  It's quite
funny to keep hearing that a 'newer' paper will allow us to ignore prior
papers that are irritatingly at odds with popular theory.  The correct
approach is to evaluate the differences in the approach of the papers, to
see which is right.

Thanks for the specific references.

"Stellar Orbits Near Sagittarius A*," Eckart, Genzel, Schodel, Jan 2002

Mixes data types:
Combines the high precision but shorter time scale NIRC/Keck data with the
lower precision but longer time scale SHARP/NTT data set;

"Adjusts" data:
Statistically corrects the observed accelerations for theoretical projection
effects;

Drops "contradictory" data:
Excludes star S8 from the analysis of the amount and position of the central
mass. ("... this star either was or is subject to a close interaction with a
different object or that its position measurements are influenced by the
emission of a different cluster star.")

"Closest Star Seen Orbiting the Supermassive Black Hole at the Centre of the
Milky Way", Oct 2002, Schodel et al.

23 authors (I'm afraid I'll always start out highly skeptical of such an
obviously political effort).  One star as primary data.  Mixing of VLBI and
infrared data.  "Correcting" data to match theory (Sgr A* position was
'moved' to fit the theory).  No mention of the other stars that don't seem
to be moving in this fashion.

"Stellar Dynamics in the Central arcsecond of our galaxy," June 2003,
Schodel et al  Followup from 0210426.  6 Stars plotted.  Retains the
"adjusted" data (postion of Sgr A*).

None of these address all the stars found in the Rieke's paper.
Specifically, instead of focusing on one or a few individual stars selected
for their apparent support of one theory, one needs to address the following
findings from Rieke and Rieke:

"The simplest model with a central black hole that dominates the mass within
2 pc would have a velocity dispersion increasing as r^-1/2; clearly there is
no indication of this trend in our data. A chi^2 analysis indicates there is
a 95% probability that the stellar velocity dispersion for r < 0.5 pc ... is
less than 120 km s^-1.  Perhaps the most important result of this letter is
that the upper limit of 120 km s^-1 ... is far below the velocities observed
for gas in this region, which vary over +- 300 km s^-1. ..."

greywolf42
ubi dubium ibi libertas


subject: Re: Galaxies without dark matter halos?

text:
g> LOL!  We don't get to pick and choose our data, in science.  It's
g> quite funny to keep hearing that a 'newer' paper will allow us to
g> ignore prior papers that are irritatingly at odds with popular
g> theory.  The correct approach is to evaluate the differences in the
g> approach of the papers, to see which is right.

At the risk of stating the obvious to other readers in this newsgroup,
greywolf's last statement is implicit in the references to newer
papers.  To take just two examples that have appeared in the newsgroup
recently:

* The Galactic center:  The IR observations have made enormous
  progress over the past 5 years or so by using adaptive optics and
  related techniques.  I gather that subarcsecond imaging in the GC is
  now nearly routine (if the weather cooperates of course! :).  Thus,
  which observation of stars is more likely to be constraining for a
  model: One at 2 arcsecond resolution or one at 0.2 arcsecond
  resolution?

* Globular cluster ages: Globular cluster ages are determined from
  stellar models and an HR diagram.  A crucial aspect of this
  determination is the distance to the globular cluster as it affects
  our estimates of stellar luminosities.  Recent Hipparcos distance
  determinations, which are much higher in accuracy and precision than
  previous estimates, have shown that globular clusters were a bit
  more distant than thought.  In turn, that means the stars in them
  are brighter and therefore younger.  Thus, newer globular cluster
  ages are more reliable because they are based on better distance
  estimates (and I think improved stellar models as well).


author: Craig Markwardt

subject: Re: Galaxies without dark matter halos?

text:
greywolf42 <[email]> writes:
[ ... ]

The three factors you bring up are *differences* between the Eckart
work and previous work by Ghez et al (2000).  Despite this, the
results of Eckart and Ghez are consistent with one another, and with
the previous work by Genzel et al (2000).  Furthermore the techniques
applied by the Eckart paper appear to be appropriate, and would tend
to *decrease* rather than increase observational biases.  Therefore
your criticisms appear to be essentially irrelevant.

Your "political" comment is irrelevant.  Your other comments imply
your disapproval.  However, as the authors say, "

  The remarkable consequence of the orbital technique is that the mass
  can be determined from a single stellar orbit, in comparison to the
  statistical techniques that use several tens to hundreds of stellar
  velocities at 10 to 300 light days from SgrA* (Fig. 3). In addition,
  the orbital technique requires fewer assumptions than the other
  estimates (for example, equilibrium and isotropy of orbits), and
  thus is less vulnerable to systematic effects.

The combination of VLBI and infrared data allows an extremely precise
alignment of the stars (IR) and Sgr A* (radio).  The position of Sgr
A* can be considered a nuisance parameter since it is not relevant to
the mass determination (and in any case is within 1.6 sigma of the
previously determined position).

Genzel et al (2000) show, using an ensemble of stars, that the central
velocity dispersion is of order 280-350 km/s, and decreases with
radius between r^-1 and r^-0.5, so Rieke's findings appear to be
addressed.  However, these statistical measurements really take second
place to a direct measurment of a Keplerian orbit around the central
mass, including both pericenter and apocenter, which both clinches the
mass of the central body, and highly constrains its density (since
pericenter is within 17 lt-hr = 120 AU).

CM

References
Genzel, R. et al 2000, MNRAS, 317, 348
Ghez, A. M. et al 2000, Nature, 407, 349


subject: Re: Galaxies without dark matter halos?

text:
Joseph Lazio <[email]> wrote in message
news:[email]...

LOL!  It's not 'implicit.'  You assumption is that 'newer' papers must be
more correct than 'older' papers.

A complete strawman.  Precision in resolution isn't the issue.  Ignoring
contradictory data is the issue.

It's not the higher precision, per se, that caused the change.  The reason
for the change in globular cluster distances with Hipparcos was that
parallaxes for low-mettalicity halo stars were determined for the first
time.

It is because they are based on measurements, instead of just theory.   The
low-metallicity simulations 'should' change to meet these new requirements
(I don't know if they've shifted, yet.)

greywolf42
ubi dubium ibi libertas


subject: Re: Galaxies without dark matter halos?

text:
Craig Markwardt <[email]> wrote in message
news:[email]...
the
projection
central
with a

No.  These are specific quotes from the specific references.  I made no
attempt to compare these to 'previous work.'

My observations of questionable manipulations of data are not irrelevant at
all.

the
and
seem

It was a statement of a bias on my part.

Yes.

I care not what the authors say.  One data point does not a definitive study
make.  As there are other stars observed in the same region that have been
observed to contradict the conclusion.  (We don't get to 'pick' the data we
like, and ignore the rest, in science.)

No comment provided on this study.

selected
following
within
there is
there is
... is
is
observed

This paper is not the three provided, above, and under discussion.  What is
the need for constantly proffering different studies?  Can't you just
address the issue, above?

Nonsense.  Rieke's findings are not addressed at all.  That you have found a
study that appears to contradict Rieke, does not mean that Rieke is the
paper in error.  One must actually 'address' Rieke's study to 'address' the
study.  (i.e. identify a likely source of error in one or the other)

In this you are flatly incorrect -- because you are 'picking' out the data
you prefer.  One star does not a galaxy make.

Thanks, but I'll pass on bothering with these two -- until you address the
issue above, based on the first set of studies you claimed 'addressed'
Rieke.

greywolf42
ubi dubium ibi libertas