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Re: (meteorobs) A-T 1996 ZAYGE ...long article
In a message dated 96-09-17 12:51:51 EDT, you write:
<< George,
What bothers me about your "analysis" and last e-mail? Let me count the
ways.
1. Your previously defined attitude about the A-T's:
On 1995 August 19, Kevin asked you a simple question about the A-T's and
you responded on 1995 August 20 with, "No real radiant...probably best to
not favor any possible radiant at this stage." Considering that on the
latter date you also wrote to Marco Langbroek and wrote, "I really don't
know too much about this possible radiant," it would seem you were not in
a position to judge the radiant that way. Considering that extensive
articles were written about this stream and published in WGN and Meteor
News, you need to do a little more reading on a subject before
considering yourself qualified enough to make such a judgement call.<<
Well Gary, I don't remember the whole contexts of those messages, but I
believe at that time I was trying not to refer to any particular area within
the A-T region. I was concerned about biasing people so that a radiant would
materialize unintentionally. I was also concerned about this possible shower
to be not real due to nothing in my previous data indicated a radiant and
didn't want to suggest too much to others...again not wanting to bias other
observers...particularly the newer ones.
>> 2. Your "Scientific" Method:
I am writing this at work and your response to me last night is currently
at home, but I believe you mentioned something along the lines of maybe I
was wishing too hard for the A-T's to be real and something about my
scientific methods for studying this stream are not based on observations
by experienced observers.
Okay, here we go (deep breath taken here, considering much of what
follows was withheld yesterday because I did not want to cause problems).
First of all, I have put as much into the A-T's as I have every other
minor shower I have investigated over the past 15 or so years. The same
data gathering methods were used. The same computer programs (which I
wrote mind you and have tested thoroughly) were used for orbital
computations. Considering I am working feverishly to finish volume one of
Cometography for my deadline next April, I do not a lot of time to dwell
extensively on meteor streams. I just pause by writing, investigate the
stream to death to determine it validity, and let people know about it. I
am sorry if my having accidentally found this stream poses a problem for
you.<<
Gary...if the stream proves real in the long run..dot it poses no problem to me.
But I'm not going to roll over and pretend that I saw something when I didn't
and be quiet about it. Not seeing something is just as important as to seeing
something. It could mean your conclusions about an A-T stream is wrong or a
stream may be periodic?
>> Second, the observers who have seen this activity are experienced. I
have
over 20 years of meteor observing experience. George Gliba has also been
around a long time. The current record holder (albeit posthumously) is
Cuno Hoffmeister, whose plots over a period of about 30 years revealed
several thousand radiants. He detected the A-T's in six different years,
including 1934, when it was also seen the same night by an observer in
the United States. Hoffmeister's radiants were all listed in his 1948
book Meteorstrome. The list of AMS observers who plotted A-T radiants
include several of that organization's most active observers of all time:
Franklin W. Smith (1934, 1940), Charles E. Worley (1950, 1951), and
Jeremy H. Knowles (1951, 1955). There were also many others.<<
Well, I don't know how many actual hours of plotting time you have in these
last 20 years since I can't find any of your totals. I know your totals for
1993 isn't very high from what I saw in AMS's Annual Report. I have found
Gliba's for the past few years in IMO's Observational Report Series and it's
not too impressive. Perhaps your plotting efforts aren't reported? I don't
know? One can look at the sky for many years, But plotting skills aren't
acquired thru osmosis. If the practice of plotting isn't frequent, the skill
isn't usually maintained.
>> Now for your method of analysis.
It is not very scientific to conduct what appears to have been intended
to be a definitive analysis by using the observations of only one
person--in this case, you.<<
You got to start somewhere! I made mine as complete as I know how...granted I
don't have the computer skills to make it look pretty, but all that means it
took me longer to do what I did by hand. Now, if someone else has data, they
will at least have one source out in the open. Outside of myself and
Lunsford, I haven't heard anyone else reporting any extensive observations
during the A-T observing period.
>>As I continue to analyze the Xi Draconid
stream found by Bob Lunsford, yourself, and several European observers in
June, I find that where three of the radiants are very close to each
other, two are not and one of those is yours. You and Bob Lunsford
observed the same night, at the same location, and saw essentially the
same meteors, yet your radiant does not fit in well with the majority of
the observers. With this in mind, how can I, or anybody for that matter,
trust your analysis of the A-T's based solely on your observations? Your
observations are great for the Xi Draconids, when combined with everyone
else's, but I would not do an analysis of that stream based solely on
your observations. It would prove nothing, especially in lieu of the fact
that the historical data favors the radiants determined by Lunsford,
Langbroek, and Haver. Here are the radiants and the parabolic orbits I
computed for them. As you can see, your radiant causes an inclination
decrease, which is an important factor in stream analysis.
Date RA DEC w W i q e Desig
274 +54 197.8 81.6 49.1 0.991 1.0 Zay
280 +53 199.1 81.6 53.2 0.987 1.0 Lunsford
1996/06/15 280 +55 196.3 84.5 52.2 0.995 1.0 Langbroek
284 +54 198.3 87.9 54.2 0.990 1.0 Haver
283 +58 191.9 88.0 52.8 1.005 1.0 Gorelli<<<
Well, as for the Xi Draconids...I'm nowhere near 100% confidence that this is
a real shower either...too early too tell...still needs some more plotting
from years to come. I don't plot with an effort to match someone else's
efforts. As for being "off" with my "radiant" on the the Xi Draconid area and
trying to compare it with my criteria for an
A-T radiant..dot it's quite moot really. It's not that far off. The same
difference in distance between mine and Bob's for the Xi Draconid area would
have qualified it as being within one radiant on the A-T analysis. In other
words I was quite lenient in allowing areas to be considered as an A-T
radiant.
>> Another point you always seem to focus on is the apparent velocity. This
once again was a major focal point in your little analysis of the A-T's.
If I remember correctly, your velocity estimates for the Xi Draconids
were exorbitant and contradicted those of every other observer. In fact,
they indicated not only hyperbolic movement, but excessive hyperbolic
movement.<<
For shower membership, apparent velocity is important. If you have a very
fast meteor passing thru a questioned radiant area or coming very closely
from, I would have to eliminate this meteor as a possibility....for any
meteor radiant irregardless what their geocentric velocity is suppose to be.
That close to a radiant, any meteor will appear slow to even slower. If the
geocentric velocity of a shower is very fast, then I would expect to see very
fast meteors at roughly 45 degrees or more from a radiant...unless it appears
low on the horizon. Or the radiant is low on the horizon.
As for my speed estimates of the meteors from the Xi Draconid area being
very high...this is with the assumption that the Xi Draconids are real. I do
know that Lunsford reported fast meteors from this area that nite because we
talked about it. Unless we observed hyperbolic meteors that nite(though not
likely), it may be good evidence that this shower doesn't exist....on the
other hand, discriminating between a 4 or 5 on the speed scale is no big
deal. The important thing is to make sure that any speed relationships
between a meteor and it's distance from a radiant is within reason. I believe
some of the European observers likened the meteors from Xi Draconid as being
comparable to that of the Lyrids(49km/s)..a 4 on the speed scale....Lumping
an observation of 4(Fast) and a 5(Very Fast) together is within reason for
coarse judgements of speed. If you announced that the A-T's had a speed that
appeared Fast or Very Fast, I would have accepted both in final judgements
for speed estimates. In the A-T case, I've only heard of "medium"(3) to
"medium fast"(4) as being speed estimates. In my A-T analysis, I accepted not
only Medium and Fast, but included Slow since I interpreted Medium as to
being a possibile vision for Slow meteors as well. I was quite liberal in my
judgements...all in favor of an A-T radiant. An error on judging between a
Fast meteor and that of a Very Fast meteor is lot more likely as with judging
the "Xi Draconid" meteors last June, than mistaking a medium to medium Fast
with that of a Very Fast meteor because the spread is larger.
>>>Despite the statements of others, including myself, you were
not willing to admit you might have made a mistake. This is bad science.
Even in the face of something quite impossible, you stood your ground,
and this lack of a willingness to give-in causes your data to have to be
used, which subsequently pollutes the final results. <<<
Do you expect me to make my data match others when it doesn't agree? Nothing
definite has been proven about the Xi Draconids...so why should I change? My
data might simply mean that the Xi Draconids were a fluke? After all, I only
plotted 10 possibles from a 2 day period...I just noted that one was labled
as a Sagittarid, so we are probably looking at 9 now. I haven't gone thru it
too heavy for any possible eliminations the way I did with my observations
for the A-T area this month...But a couple eliminations there could have
serious implications about a Xi Draconid radiant being real. This too is
still within the realm of sporadic back ground activity. When I make my
announcements about a possible radiant, it is with the intent to bring it to
the attention of others who might be observing to see if they have anything
to back it up or at least an area to take notice in the future. To call any
suspicious activity a shower based on one year's worth of very weak evidence
isn't a good practice. It may take a few years...even many if something is
periodic. ...But to change my data to make an overall picture appear in
focus is very bad science.
>>> To conclude, as far as I can tell from what I read, you took YOUR
plots,
which are of questionable precision (based on what I found with the Xi
Draconid data), you took YOUR apparent velocities, which are of
questionable precision (based on what I found with the Xi Draconid data),
and you basically....eye-balled it? Is this correct? You said nothing
about measuring the beginnings and ends of the plotted trails, and you
did not mention any mathematical method used for the analysis. Is this
your definition of the scientific method?
Gary Kronk<<<
Yes Gary, I took my plots and my apparent velocities and eye-balled it and
was very liberal in favor of your A-T radiant...almost to the
ridiculous...and found nothing to support A-T activity for 1996. In my
analysis, I included meteors that passed within several degrees at an
intersect and called it a possible radiant. I didn't strictly stick to a 2 or
3 degree intersect point, but gave it a wider area of acceptance. I did this
with the understanding that precise measurements weren't being made.
As an update here...last night I took all of my plots for the 3 nights at all
speeds and ran them thru the same procedures....There were no improvement for
an A-T radiant showing itself.
As to measuring the beginnings and ends of the plotted trails...this is
covered in the analysis in step 2 under "MY ANALYZING PLAN". The actual
measurements aren't listed, but done by looking at the plots themselves. You
don't need to go thru some mathematical gymnastics to compare something that
is obvious..dot it's like judging which is longer 1 inch or 2 inches? ...But
here I was again very liberal in favor of an A-T radiant. I used the criteria
that "I would eliminate the meteors whose distance from a radiant to the
meteor's beginning point was less than twice the meteor's path
length"...Actually, I wasn't that critical. If the meteor was even remotely
close to this relationship, I included it as a possible A-T meteor to be
further considered in the other steps. The meteors to each of the possible
10 radiants were judged separately.
In this sort of analysis, a mathematical model of things to the "nth" detail
isn't necessary since no one's...not even yours was done with any precise
instruments that I'm aware of...for things such as velocity measurements,
meteor positions or path lengths etc. I'm merely pointing out the likelihood
of a showers existence from visual observations...the same as you have. If
anything more precisely was done by you, then an exact radiant should be
present.
George Zay
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