HDTenEightyP/NetNews huggingface dataset:
From: scott@cs.uiuc.edu (Jay Scott)
Subject: Re: averting doom
Organization: University of Illinois at Urbana-Champaign
Date: Thu, 31 Dec 1992 23:47:22 GMT

John McCarthy writes:
>By the way, it seems to me that if the above idea is sound, it settles
>the question of the stability of the solar system - in the negative.
>Very likely an asteroid could be tamed over a sufficiently long time
>with as small an expenditure of delta-v as might be desired.  Once
>tamed it could be used with infinitesimal external force to expel a
>planet from the system.  This tells us that the current trajectory of
>the solar system is arbitarily close to one in which a planet is
>expelled.  Of course, the probability that a planet actually would be
>expelled by this mechanism in some particular finite time is extremely
>low, because maintaining the required sequence of encounters requires
>an improbable precision in the initial conditions.  I suppose a lower
>bound on the probability could be computed and from it an expected
>upper bound on the gravitational lifetime of the solar system could be
>obtained.

Without being so rash as to do any actual calculations, I
would guess that this does not say much about the stability
question. I would guess that an asteriod is so much more likely
to be ejected from the solar system, or smashed to dust by
collisions, or fall into a planet, than to be captured into
a destructive resonant orbit that the asteriods will all be gone
before they destabilize the solar system.

I guess that light pressure effects or gravitational radiation
are more likely limiting factors. But don't listen to me, I don't
even know which one is bigger for planets (light pressure effects
are bigger for small objects).

	Jay Scott
	scott@cs.uiuc.edu
From: carlip@landau.ucdavis.edu (Steve Carlip)
Newsgroups: sci.astro
Subject: Re: The Hole Story
Date: 24 Dec 92 06:20:07 GMT
Organization: Physics, UC Davis

In article <1992Dec23.051529.16459@sfu.ca> palmer@sfu.ca (Leigh Palmer) writes:
>[...]
>That being the case, one cannot infer from the existence of plane wave 
>solutions that waves generated by, for example, a binary compact sytem, 
>will exist which are solutions of GR.[...]
>Thus we return to the question of whether a binary compact system can 
>radiate. It is not immediately obvious to me that it should radiate plane 
>waves (indeed that possibility is ruled out because plane waves are 
>infinite in extent). Does a radiative solution to GR exist which has a 
>symmetry more appropriate to the case of the binary pulsar?
>
There are no known exact solutions to GR describing gravitational radiation
of a physically realistic source, unless there's been amazing progress in
the past year.  But
(1) There are rigorous _existence theorems_ for radiative solutions with
isolated sources (see Cutler and Wald, Class. Quantum Gravity 6 (1989) 453);
and
(2) there are systematic approximation schemes with reasonably rigorous
justifications.  I have one reference that says that Damour and Schmidt
have a proof that one such approach (the "post-Minkowskian expansion") 
gives an asymptotic series, but I don't know where this is published.

To be fair, the solutions Cutler and Wald prove to exist aren't binary
pulsars --- they don't have the appropriate stress-energy tensor as a source,
and they radiate away _all_ of their mass.  From my quick look at the
literature (hey, it's vacation), one of the main problems seems to be
realistically modelling the details of the matter configuration, which
is not surprising (try this with Newtonian gravity).  And there is work
to be done to establish the connection between short-distance approximation
schemes and exact results at large distances more rigorously.  However, I
haven't seen any hint of evidence that there's something fundamentally
flawed with the approximation methods now used, and the existence theorems
certainly establish that at least some compact systems radiate.

Nonstandard disclaimer: I work in quantum gravity, not classical GR, and it's
certainly possible that I'm missing or misunderstanding something.  

Steve Carlip
carlip@dirac.ucdavis.edu
Organization: Johannes Kepler University Linz - Computing Center
Date: Wednesday, 30 Dec 1992 14:36:21 CET
From: <K3032E0@ALIJKU11.BITNET>
Newsgroups: sci.astro
Subject: Re: Naming asteriods question..

There ARE lots of minor planets named after people: The discoveres wife,
girlfriend, father, mother or sciencists, musicans... A few asteroids ARE
named after POLITICANS: As far as I know, there is a "Karl Marx" up there.
But I think the IAU comission will not accept such names any more.

So try this:
Go out, find a new asteroid, and use any clear night for four or five years for
follow-up-observations so it's orbit can be determined accurately. After the
litte "space rock" has been numbererd by the IAU, the discoverer (>>>YOU|<<<)
has the right to name it. You may try "JFKennedy" after the famous observatory
where this litte world has benn discovered... :)

  Good luck|
    Herbert
From: j.jahn@abbs.hanse.de (Jost Jahn)
Newsgroups: sci.astro
Subject: Sunspots at 26.12.1992.
Reply-To: j.jahn@abbs.hanse.de
Date: 26 Dec 92 08:49:00 MET
Distribution: sci
Organization: ABBS AstroMail, D-W 2121 Dahlenburg / Germany
X-Version: ZerUU V6.45c

Message-Id:   <25359782014@amterm1.abbs.hanse.de>
Sunspots at 26.12.1992., 0 h UT.

No.    Pos.  Cl.  Ar.  Mag. SF  F  M  X
---------------------------------------
7370 09S 64W Cso   40   b
7372 12S 35W Bxo   10   b
7374 09S 18W Dao  180   b    1
7378 12N 00W Hax   50   a
7379 11S 27E Hax   60   a
7381 06N 30E Dao  100   b
7382 16S 47E Bxo    0   b


No optical or x-ray flares yesterday observed.


 
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Newsgroups: sci.astro
From: johno@sdd.hp.com (John Ongtooguk)
Newsgroups: sci.astro
Subject: Re: Binoculars, exit pupil size, etc...
Date: 31 Dec 1992 06:28:38 GMT
Organization: Hewlett-Packard, San Diego Division
Distribution: na
NNTP-Posting-Host: hpsdlg10.sdd.hp.com

In article <1992Dec29.214956.21771@macc.wisc.edu>, bunner@vms.macc.wisc.edu (Dana A. Bunner) writes:
|> 
|> So where does this leave us?  The CLASSIC 7x50 is out due to having a 
|> 7.14mm exit pupil.  The 10x50 is good if you have rock-steady hands or
|> a tripod (or a tree to lean against) but is next to unusable for me and
|> several others I've spoken with if used free-standing.........  
|>         .......... I did once read a British Astronomical publication
|> which dealt with these subjects and they recommended that an 8x50 was
|> the single best binocular, of course I've never seen one of these offered
|> for sale.

   The 7x50 is usually a firm's best effort with the good oculars
   having nice eye relief, usually much more than that offered by
   10x50's and especially 10x50's with wide angle oculars. I can 
   barely manage 7X free standing and my 10X to 20X finders and
   spotters are useless without a tripod, which is why I wanted
   binoculars in the first place. So one may waste a little light
   sometimes with a 7mm exit puil, so what, it's still easier to
   use free standing than a 5mm exit pupil which evidently for most 
   people would require exact, steady alignment to avoid image
   blackout. 

   Aus Jena sells some 8x50's which are also the type that the
   S&T intro package seems to like but they cost a lot and are
   short in eye relief. Perhaps the perfect binocular is one 
   which would allow eyepieces to be changed, and maybe even   
   90 degree eyepieces so that tripod use is practical.

   John Ongtooguk (johno@sdd.hp.com)
From: det@bigbootay.sw.stratus.com (David Toland)
Newsgroups: sci.astro
Subject: Re: Averting doom
Date: 27 Dec 1992 16:20:14 GMT
Organization: Stratus Computer, Software Engineering
NNTP-Posting-Host: bigbootay.sw.stratus.com

In article <1992Dec27.070033.18932@hpcvaac.cv.hp.com> billn@hpcvaac.cv.hp.com (bill nelson) writes:
>Also, to move the Earth into a higher orbit, you would not speed the
>Earth up - you would slow it down.  The Earth orbits the sun about
>3 miles/second faster than Mars does. 

A little knowledge.....

Although the velocity of Mars along its orbital path *is* lower, its
angular momentum is higher.  You would indeed need to *increase* the
Earth's velocity in its present orbit, which would paradoxically result
in it attaining a greater distance from the Sun with a *lower*
orbital speed.  The increase in speed would need to be applied over
a multiple of 1 revolution if you want the final orbit to also remain
nearly circular.

By the way, Niven's enginering, although not perfect, stands up better
than that of *most* SF writers...
-- 
--------------------------------------------------------------------------
All opinions are MINE MINE MINE, and not necessarily anyone else's.
det@phlan.sw.stratus.com   |  "Laddie, you'll be needin' something to wash
                           |  that doon with."
From: tonya@hpldsla.sid.hp.com (Tony Arnerich)
Date: Tue, 22 Dec 1992 23:02:43 GMT
Subject: Re: Coulter Dobsonian Telescopes;  Opinions?
Organization: HP Scientific Instruments Division - Palo Alto, CA
Newsgroups: sci.astro

bunner@vms.macc.wisc.edu (Dana A. Bunner) writes:

[Coulter 13" comments]
> I have found my Coulter to be less than hoped-for on planetary and
> double-star observation but very good on deep-space objects.  Also
> at powers higher than 200x, I've never achieved a sharp focus.  A 
> recent collimation helped but everything is very noticably fuzzy
> at 240x.  On the other hand, at 60-120x, it is wonderful.  I usually
> use either a Meade extra-wide 24.5mm or super-wide 13.8mm plossl.

> Dana Bunner

FYI I compared a Coulter 17.5" and an Astro-Physics 5.1" Starfire triplet
refractor side-by-side, with the same eyepiece (9mm Nagler). The Starfire
fairly easily showed the 5th member of the Trapezium group, while in the
Coulter there was no evidence of it whatsoever. However, the Coulter did
an absolutely incredible job on the nebulosity of M42 - simply stunning.
From: Mike.Bloodworth@f875.n800.z3.fidonet.org (Mike Bloodworth)
Newsgroups: sci.astro
Subject: WEATHER PICTURES IN AREA-8
Date: Sun, 27 Dec 1992 10:57:30

* Original Area: Auspak
* Original To  : Weafax (3:800/875)

Hi All,  Hope you all had a Merry Xmas.  I have greatly improved the weather
pictures from GMS-4 Satellite by several factors.
     (1)  Improved Signal Strength by modifications to the 1.2 M parabolic     
     dish aerial.
     (2)  Re-Adjustment of the 2nd IF in the receiver for wider bandwidth      
    giving a better noise figure at high FM deviations of +/- 126 KHz
     (3)  Colour Enhancment added, improving the temperature gradients
     (4)  Added a Colour Bar with corresponding Temperature scale from
          -80 Deg C to +30 Deg C ...White,Pink,Red,Orange,Green,Blue,Purple    
      and Black corresponding to a Bar inc of about 7 Deg C.
     (5)  Added TEXT to GIF Picture giving General information and special
          events together with the Date/Time at Gawler, South Australia.

Note ....Some Gif pictures in Area-8 have the wrong DOS date Stamp due to a
Clock problem on the Computer at the Land receiving Station at my place.
This has now been fixed.  Always take note of the file name  which consists of
a description, day, month and extension of GIF.
Typical are  Quad2612.Gif        .....3rd Quadrant of the Earth on 26th Dec.
             SA2612.GIF          .....Zoomed from Quadxxxx.Gif file of
Adelaide
             Aust2612.Gif        .....Zoomed from Quadxxxx.Gif of Australia
             Qld2612.Gif         .....Zoomed from Quadxxxx.Gif of Queensland
...and so on!
..................Only REGISTERED USERS HAVE ENOUGH TIME/Download Capacity to
                  get these files.  If you are not yet a Member please call in
the Shop of ACRO and ask for Bob, who will supply you a copy of QUAD2612.GIF
for the cost of a disk providing the shop is not to busy.  We suggest you phone
Bob and arrange for disk to be available to you when you call.
Phone No. (voice) (08) 262-7075

Join the Club and get Access to many more file areas and the CD-ROM.
Cost to join the club is $30 /Year.  Ring Bob for more details.

............................Cheer's   Mike Bloodworth    "Sysop of 3:800/875"


 * Origin: THE ACRO CONNECTION BBS: One heck of a place to be. (3:800/875)
From: j.jahn@abbs.hanse.de (Jost Jahn)
Newsgroups: sci.astro
Subject: Sunspots at 01.01.1993.
Reply-To: j.jahn@abbs.hanse.de
Date: 01 Jan 93 12:12:00 MET
Distribution: world
Organization: ABBS AstroMail, D-W 2121 Dahlenburg / Germany
X-Version: ZerUU V6.45c

Message-Id:   <25890374311@amterm1.abbs.hanse.de>
Sunspots at 01.01.1993., 0 h UT.

No.    Pos.  Cl.  Ar.  Mag. SF  F  M  X
---------------------------------------
No sunspots on the solar disk or no report available, sorry.

Explanations of spot columns:
No.  Running number of sunspot group.
Pos. Position in Latitude and Longitude.
     N - North, S- South, E - East, W- West.
Cl.  MacIntosh classification.
Ar.  Area in 10-6 of visible hemisphere.
Mag. Magnetic Classification.
     a - alpha, b - beta, bg - beta/gamma,
     g - gamma, bd - beta/delta, bg - gamma/delta
     bgd - beta/gamma/delta.
SF   Number of subflares.
F    Number of optical flares. (importance > 1).
M    Number of medium x-ray eruptions.
X    Number of strong x-ray eruptions.


No optical or x-ray flares yesterday observed.


 
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------------------------- for amateur astronomers ----------------------------
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Newsgroups: sci.astro
From: metares@well.sf.ca.us (Tom Van Flandern)
Subject: Re: Is P/Swift-Tuttle a Record Breaker?
Keywords: comet period record apparition
Organization: Whole Earth 'Lectronic Link
Date: Wed, 23 Dec 1992 02:37:25 GMT


pg@sanitas.stortek.com (Paul Gilmartin) writes:

> What comets having longer period than P/Swift-Tuttle have been observed
> on multiple apparitions?  The decade uncertainty in the prediction of S-T's
> current apparition and the difficulty of identifying its 1737 apparition
> suggest that there might be very few.

     The record holder is still Herschel-Rigollet, which appeared in 1788 and
1939 (present period 155 years).  Swift-Tuttle is now next with a current
period of 134 years.  Comet Halley at 76 years is the third-longest-period
comet of more than one observed apparition.  -|Tom|-

-- 
Tom Van Flandern / Washington, DC / metares@well.sf.ca.us
Meta Research was founded to foster research into ideas not otherwise
supported because they conflict with mainstream theories in Astronomy.
Newsgroups: sci.astro
From: bunner@vms.macc.wisc.edu (Dana A. Bunner)
Subject: Re: Binoculars, exit pupil size, etc...
Organization:  University of Wisconsin Academic Computing Center
Distribution: na
Date: 29 DEC 92 15:12:43    

In article <1992Dec29.144420.1@stsci.edu>, gawne@stsci.edu writes...

Enjoyed your post Bill, but...

>BUT if instead of 11x80's you were to use 20x80's with a 5mm exit pupil

I believe this would be a 4mm exit pupil.  Sort of throws off the 
subsequent calculations.  But who I am to point fingers, I forgot to
factor in focal lengths in a previous post.

>So where is this all going, you ask?  My point is that very few people 
>using binoculars for astronomy have pupils that dilate to 7mm.  You are
>much better off getting binoculars with a 5 or 5.5 mm exit pupil and
>getting ALL the light into your eyes.

So where does this leave us?  The CLASSIC 7x50 is out due to having a 
7.14mm exit pupil.  The 10x50 is good if you have rock-steady hands or
a tripod (or a tree to lean against) but is next to unusable for me and
several others I've spoken with if used free-standing.  This would suggest
to me that the best all-purpose carry around design would be an 8x40/42 or
7x40.  It also suggests that popular models such as the 8x56 would be
better replaced with something like a 11x56 (which seems to be a pretty
rare bird), and that the lion's share of night binoculars sold today are
ill-suited for their owners ... this based on the popularity of the 7x50,
8x56, 9x63, 10x70, 11x80, and even 14x100.  While designs like 12x60 and
14x70 are less common.  I did once read a British Astronomical publication
which dealt with these subjects and they recommended that an 8x50 was
the single best binocular, of course I've never seen one of these offered
for sale.

It seems odd that nearly all buying guides and astronomical publications
suggest the 7mm-type models as preferable.  Since I'm approaching 40,
I opted for 6mm and nearly selected a 5.25mm design.
Newsgroups: sci.astro
From: chaloux@mandolin.mitre.org (Dave Chaloux)
Subject: Barlow Lens
Reply-To: chaloux@mandolin.mitre.org (Dave Chaloux)
Organization: The MITRE Corporation, McLean, Va
Date: Tue, 29 Dec 1992 17:31:14 GMT

In writing about the Astrophysics refractors, I failed to mention a test that
we did. We happened to have both a Astrophysics 2" 2x Barlow and 9mm and 4.8mm
Naglers on hand. An obvious thing to do was to look at Mars through the
Barlow and 9mm combination and compare that to the image through the 4.8mm
Nagler. In short the 4.8mm Nagler was significantly sharper. Detail that was
there for the taking was gone using the Barlow.

Another somewhat annoying thing was that when used with the 2" Star Diagonal, the
Barlow and a 7mm Nagler would not reach focus. The reason the 9mm would and the
7mm would not was fairly obvious. Specifically, the 1 1/4" adapter needed for
using the 7mm Nagler kept in slightly to far out. It came close to being in
focus but not quite. I suspect that a recessed 1 1/4" adapter would have
reached. The 9mm Nagler can be used in either the 1 1/4" adapter or straight
as a 2" eyepiece. We used it as a 2" and it was thus able to reach focus.

I personally don't feel these problems were very significant. The 9mm with
Barlow vs 4.8mm Nagler test was strictly a matter of curiousity.

The fact the 7mm Nagler with Barlow didn't work is probably correctable and
frankly, was not really missed. It would be nice for very close double stars
where it would give 348x (58x / inch).

Something we could have tried but didn't think of at the time was using the
9mm and the Barlow ahead of the diagonal. This would have given about 406x
(68x/inch). Such high powers would not normally be used but are helpful for
close doubles. I think that combo probably would have reached focus.
From: joe@woody.mpd.tandem.com (Joe Senner)
Newsgroups: sci.astro
Subject: binocular question
Date: 28 Dec 92 15:09:16 GMT
Reply-To: joe@mpd.tandem.com
Organization: Tandem Computers Inc., Austin, TX.

a few weeks ago I posted about my purchase of a dept. store telescope
(you know the kind, 200billion power, plastic everything, etc). I got
a lot of responses and some really good information, I want to thank
those of you who responded (more than once in some cases). Thanks!
anyway, the scope has gone back to the store accompanied with the 
requisite complaints about the poor quality and the danger of the
sun filter. 

my wife and I have since read through a couple of astronomy mags and
a book or two, added a little cash to the pool and started down a new
and hopefully better path. we found a local business that had a fairly
good inventory of celestron scopes and binoculars, and other various
brands of binoculars. the celestron binoculars that they had in stock
were either the very small (35mm) sport type or the very large "comet
chaser" things (>$800). they had a good stock of 7/10/16x50s in minolta,
pentax, and a couple other brands. after a while we narrowed it down to
two, a 10x50 minolta and a 16x50 pentax. the 16x50's were significantly
lighter than the 10x50's surprisingly enough, but did magnify the jitter
considerably. both appeared to have excellent optics. all reflections
from lenses were a rich green or blue and there was no obvious deformation
of things at the edges. since we have a large camera tripod and can easily
attach the binoc's to the tripod, we opted for the 16x50's (although
Mrs. Santa winced a little at the >$300 final bill :)

the binocs appear to work quite well, they bring out so many stars that
it takes me a couple of tries to locate anything in particular, I get
lost seeing so much through them (I almost need a finderscope for the 
binoc's :).

I guess my only concern is, should we have opted for the heavier 10x50's 
instead? if so, why? the 16's have a 3 degree field of view (narrow, I
realize) compared to the 5 degree (?) of the 10's. the 16's are a little
jittery when locating things, but once aligned on the tripod a good
stable image is available. I'm hoping that the optics have had the attention
they need for good 16x magnification, and tend to belive so given the
large price jump as compared to the 10's (10's were typically in the $100
through $200 range).

-- 
Joe Senner                                          joe@rider.cactus.org
Tandem Computers Inc.                               joe@mpd.tandem.com

        mcad.dunham-frodo[ 10 ]%make witches\ burn
        Make:  Don't know how to make witches burn.  Stop.
     Ergo, it must be the wizards." -- Jerry Dunham
From: Leigh Palmer <palmer@sfu.ca>
Subject: Re: Detecting Second-Order GR Effects in Binary Pulsars
X-Xxmessage-Id: <A75D53EF04031C1F@rs15-annex3.sfu.ca>
X-Xxdate: Tue, 22 Dec 92 07:23:27 GMT
Organization: Simon Fraser University
X-Useragent: Nuntius v1.1.1d16
Date: Wed, 23 Dec 1992 07:22:26 GMT

In article <1528@lyman.pppl.gov> Bruce Scott, bscott@lyman.pppl.gov
writes:

>the statement that there are no gravity waves in Einsteinian GR is
simply 
>not true.

Elsewhere I have addressed this question. I have accepted the statement 
that plane wave solutions of GR exist on faith. My question relates to
wave 
solutions with a symmetry appropriate to the problem under examination 
here, radiation from the PSR 1913+16 system (I'm not sure I've got that 
number right, but you know the one I mean). The radiation from that
system 
cannot be plane waves.

Leigh
From: slane@head-cfa.harvard.edu (Patrick Slane)
Newsgroups: sci.astro
Subject: Re: STS-1 DISASTER/COVERUP
Date: 23 Dec 92 11:28:21 GMT
Organization: Smithsonian Astrophysical Observatory, Cambridge, MA,  USA

From article <Bzoupo.LAo@feenix.metronet.com>, by jack@feenix.metronet.com (Jack Hudler):
> Clearly, too much LSD at an early age.

Or, in this case, perhaps not nearly enough...
Newsgroups: sci.astro,rec.radio.shortwave
From: oler@rho.uleth.ca (Cary Oler)
Subject: Daily Solar Geophysical Data Broadcast for 21 December
Organization: University of Lethbridge
Date: 22 Dec 92 11:15:38 GMT

!!BEGIN!! (1.0) S.T.D. Solar Geophysical Data Broadcast for DAY 356, 12/21/92
10.7 FLUX=145    90-AVG=138        SSN=140      BKI=0123 2232  BAI=007
BGND-XRAY=B4.8     FLU1=3.1E+05  FLU10=1.0E+04  PKI=1133 3333  PAI=011
  BOU-DEV=003,006,019,037,015,017,021,007   DEV-AVG=015 NT     SWF=00:000
 XRAY-MAX= C1.3   @ 1215UT    XRAY-MIN= B4.1   @ 2156UT   XRAY-AVG= B6.1
NEUTN-MAX= +002%  @ 1110UT   NEUTN-MIN= -002%  @ 2305UT  NEUTN-AVG= -0.1%
  PCA-MAX= +0.1DB @ 2035UT     PCA-MIN= -0.5DB @ 1110UT    PCA-AVG= -0.0DB
BOUTF-MAX=55422NT @ 1525UT   BOUTF-MIN=55388NT @ 1825UT  BOUTF-AVG=55415NT
GOES7-MAX=P:+109NT@ 2140UT   GOES7-MIN=N:-022NT@ 1034UT  G7-AVG=+073,+030,+007
GOES6-MAX=P:+128NT@ 2140UT   GOES6-MIN=E:-016NT@ 2139UT  G6-AVG=+092,-001,+035
 FLUXFCST=STD:150,155,155;SESC:150,155,155 BAI/PAI-FCST=005,005,005/010,010,010
    KFCST=0023 4210 0023 4210  27DAY-AP=013,013   27DAY-KP=2234 3332 2224 4222
 WARNINGS=
   ALERTS=
!!END-DATA!!
Newsgroups: sci.astro