HDTenEightyP/NetNews huggingface dataset:
From: sharon@comlab.ox.ac.uk (Sharon Curtis)
Newsgroups: sci.astro
Subject: Re: Calendar for 1993
Keywords: calendar, unix
Date: 31 Dec 92 11:35:46 GMT
Organization: Oxford University Computing Laboratory, UK
Originator: sharon@flint.comlab


Hi again!

Someone has very kindly pointed out to me that in my calendar which
I posted a few days ago there are a few mistakes in the historical
information. As I said at the time, I obtained the historical information
from a post about two years ago, and so unfortunately I can't correct
most of it.

As there are only a few corrections, rather than waste bandwidth by
posting the calendar all over again, I'll just tell you the corrections:

* Unfortunately there are no historical entries for the months of
January, July, August, September, November, and part of April.
If I find any, I'll let you know, but don't hold your breath.

* CRAF got cancelled, so the following lines can be deleted:
Jan. 22 1998    CRAF flies past asteroid 449 Hamburga.
Mar. 31 2003    CRAF mission ends.
Jul. 20 2001    CRAF fires a small penetrator into the comet's crust.
Jul. 6  1997    CRAF flies past Earth.
Aug. 14 2000    CRAF reaches Comet Kopff.
Aug. 22 1995    CRAF launched by Titan 4 rocket on trajectory toward cometary target.
Dec. 12 2002    CRAF and Comet Kopff make close approach to the sun.

* Unfortunately this quote is incomplete:
Mar. 14 1936   "The whole procedure of [shooting rockets into space] ...  presents difficulties of so fundamental a nature, that we are forced to dismiss the notion as essentially impractic- able, in spite of the author's insistent appeal to put aside pre

* The exact day got obscured on this line:
Oct. 1  1608  Evangelista Torricelli "discovered" outer space.  He accomplished this by inventing the mercury barometer, which which he used to calculate the height of the atmosphere.
(I make a guess at 14)


Many apologies for the errors, folks.

Sharon
Newsgroups: sci.astro
From: chris@chrism.demon.co.uk (Chris Marriott)
Subject: Re: "Moonraker" -- fact or fiction? 
Distribution: world
Organization: None
Reply-To: chris@chrism.demon.co.uk
X-Mailer: Simple NEWS 1.90 (ka9q DIS 1.19)
Date: Sun, 27 Dec 1992 12:55:22 +0000

Are the rest of these "Audio Letters" available at any FTP site?  They're
so amusing I'd like to read the rest.

Chris
-- 
--------------------------------------------------------------------------
| Chris Marriott                           | chris@chrism.demon.co.uk    |
| Warrington, UK                           | BIX: cmarriott              |
| (Still awaiting inspiration              | CIX: cmarriott              |
|  for a witty .sig .... )                 | CompuServe: 100113,1140     |
--------------------------------------------------------------------------
 
Newsgroups: sci.astro
From: clarke@acme.ucf.edu (Thomas Clarke)
Subject: Re: Astro Physics Refractors
Organization: University of Central Florida
Date: Tue, 29 Dec 1992 19:55:23 GMT

In article <1992Dec28.175507.1210@linus.mitre.org> chaloux@mandolin.mitre.org  
(Dave Chaloux) writes:
> A friend of mine recently obtained a 6" F8 Astrophysics Refractor and he
> brought it over to my Observatory for "First Light". 
> 
> This gave me a chance to compare side by side a supposedly Top Quality
> Apochromatic Refractor with my Obsession 20" F5 which is also a supposedly
> premium quality telescope. I thought I would share my impressions.
> 
I wonder if yoy thought to try a 6" off-axis mask on your Obsession versus
the Astrophysics Refractor?  I would think the views would have been
identical ??

--
Thomas Clarke
Institute for Simulation and Training, University of Central FL
12424 Research Parkway, Suite 300, Orlando, FL 32826
(407)658-5030, FAX: (407)658-5059, clarke@acme.ucf.edu
Newsgroups: sci.astro
From: lawler@ektools.kodak.com (Ed Lawler)
Subject: Re: Solstice Question (simple)
Followup-To: lawler@ektools.kodak.com 
Organization: Eastman Kodak
Date: Fri, 25 Dec 92 17:03:27 GMT

In article <7460063@hpfcso.FC.HP.COM> goris@hpfcso.FC.HP.COM (Andy Goris) writes:
>
>I have a simple question for some astronomy guru out there:
>
>   As everyone knows, winter solstice is the day with the shortest time 
>   between sun-rise and sun-set.  However, it is neither the day
>   of latest sun-rise nor earlist sun-set.  Why is this?  I'm having


It has to do with the earth's elliptical orbit as you suspect. Also, 
remember that perihelion does not occur on the winter solstice date.
Since the speed of the earth is changing because of the elliptical
orbit the time the sun crosses zenith is changing too. You can
expect the local sunrise and sunset to change  for the same reason.
It's tough to picture. You might want to try drawing an exaggerated
elliptical orbit on paper and seeing how much more arc is swung through
in one day when the earth is nearest the sun than when its furthest
from the sun.
 
Good luck,
Ed

 
Newsgroups: sci.astro,sci.space,sci.physics,sci.environment
From: hrubin@pop.stat.purdue.edu (Herman Rubin)
Subject: Re: averting doom
Organization: Purdue University Statistics Department
Date: Fri, 1 Jan 1993 12:59:26 GMT

In article <C05E2y.B7E@cs.uiuc.edu> scott@cs.uiuc.edu (Jay Scott) writes:
>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.

			.......................

>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.

From the standpoint of stability as precisely defined in the theory
of dynamical systems, a gravitational system is not stable; the effects
of a perturbation do not die out.  It is, for example, quite possible
that one of our space probes could alter the orbit of an asteroid so
that the gravitational attraction of another asteroid could cause it
to get a gravity boost from Jupiter which knocks it out of the solar
systme.  Even more so, a change of one micron/second in the earth's
speed will eventually have a non-trivial effect on the paths of
Venus and Mars.  I have not made any attempt to calculate how long
this will take.

-- 
Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907-1399
Phone: (317)494-6054
hrubin@snap.stat.purdue.edu (Internet, bitnet)  
{purdue,pur-ee}!snap.stat!hrubin(UUCP)
Newsgroups: sci.astro,sci.space,sci.physics,sci.environment
From: davem@ee.ubc.ca (Dave Michelson)
Subject: Re: averting doom
Organization: University of BC, Electrical Engineering
Date: Thu, 31 Dec 1992 00:32:41 GMT

In article <72616@cup.portal.com> lordSnooty@cup.portal.com (Andrew - Palfreyman) writes:
>I like the simplicity of this idea (moving the Earth instead of
>trying to shield it), but what the heck's all this "elastic
>collisions" stuff? Surely you're not serious about the "broken
>Kepler" business? 
>
I think John's "broken Kepler" method is essentially the "patched conic"
approximation.  Please correct me if I've misinterpreted this...
 
--
Dave Michelson
davem@ee.ubc.ca
From: bweiner@ruhets.rutgers.edu (Benjamin Weiner)
Newsgroups: sci.astro
Subject: Re: The Hole Story
Date: 23 Dec 92 00:06:54 GMT
Organization: Rutgers Univ., New Brunswick, N.J.

metares@well.sf.ca.us (Tom Van Flandern) writes:

>     But even without a black hole, it is an experimentally unsolved problem
>to learn what would happen if a non-gravitational force moves a mass off its
>geodesic path.  Would the new static field exist at infinity instantly, or
>after some delay?  If instantly, that seems to act like ftl communication.

Merely parroting the usual GR orthodoxy, I would say that if we made
a small disturbance with a non-gravitational force, we would get a
small disturbance in the metric, which would propagate at the speed
of light, as can be derived in the usual linearized gravity
approximation.  Last time we had this flamefest on sci.physics,
someone compared this behavior to the Coulomb gauge in electrodynamics,
where the static field is instantaneous but disturbances propagate
at the speed of light.

>(See the current thread in sci.physics, where it seems to be agreed that this
>type of ftl communication is not in conflict with observation or experiment.)

I disagree, the thread to which you refer is about a pathological
variation of special relativity which assumes a preferred frame.

>     OTOH if the new field is generated with delay, then there is a
>discontinuity in the force felt by remote bodies.  A test particle continues
>to "feel" and react to the predicted future geodesic path of a mass for a
>lighttime interval even after the mass has been moved off that path by a non-
>gravitational force.  Then when the new geodesic path information finally
>reaches the test particle, the particle begins to react to some future
>position of the mass.  As I said, there is a discontinuity in the action.
>Either way, something unexpected happens.

I don't think so.  In any case it is confusing to talk about the "new
[static] field" while in the Coulomb gauge.  I am going on vacation
and will not beat this particular horse anymore, though.
Newsgroups: sci.astro,sci.space
From: wagener@gown.das.bnl.gov (Richard Wagener)
Subject: Giotto Sample Return ?
Organization: Brookhaven National Laboratory
Date: Wed, 23 Dec 1992 19:47:09 GMT


From Eos 73, 1992 August 18 p. 347:

... Its [Giotto's] orbit brings it to within 210000 km of Earth on
July 1, 1999.  Although the spacecraft still has some fuel left, ESA
has no plans for more Giotto missions. - Stephen Cole

My question(s):

Is there enough fuel to change the orbit for a closer encounter
with Earth?  Could it be aerobrake'd into a stable orbit from which it
could be captured and returned by the shuttle?
Would the returned probe contain scientifically useful cometary
samples?

I would think that an aerobrake attempt should be made if it's
possible, the worst that could happen is an early fireworks display
for independence day (U.S.) ;-)
-- 
[nosave]
Tschuess ...rick...
_______________________________________________________________________________
Richard Wagener				|
From: pg@sanitas.stortek.com (Paul Gilmartin)
Newsgroups: sci.astro
Subject: Re: Averting doom
Date: 27 Dec 92 15:39:00 GMT
Organization: Storage Technology Corp.
X-Newsreader: TIN [version 1.1 PL7]

bill nelson (billn@hpcvaac.cv.hp.com) wrote:
: : 
: : Larry Niven, in "A World out of Time", suggested moving a gas giant
: : planet into Earth's orbit a few degrees ahead of the Earth.  The
: : resulting gravitational perturbation would gently accelerate the
: 
: I suspect that the tidal forces would destroy the Earth.

The arithmetic favors the engineer:  the tidal strain varies as the
inverse cube of the distance; with a big enough mass far enough 
away, you can move the Earth without crushing it.  The Moon moves
the Earth measurably.
 
: 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. 

Jmc has correctly refuted this in his followup.
From: kayser@nssdca.gsfc.nasa.gov (Susan E. Kayser NSSDC/STX (301)513-1673)
Subject: Re: "Space Potato" in Journal of Irreproducible Results
News-Software: VAX/VMS VNEWS 1.41    
Organization: NASA - Goddard Space Flight Center
Date: Thu, 31 Dec 1992 21:08:00 GMT

In article <MONTA.92Dec31033956@image.mit.edu>, monta@image.mit.edu (Peter Monta) writes...
>There's a note in the December Journal of Irreproducible Results that

It's been a while since I've seen the JIR. How can one get a copy, these days? 

Susan Kayser		NCF::KAYSER  or  kayser@nssdca.gsfc.nasa.gov
Hughes/STX at NASA/GSFC/NSSDC
Greenbelt, MD
Newsgroups: sci.astro
From: dsmith@hplabsz.hpl.hp.com (David R. Smith)
Subject: Re: My SC corrector plate is dirty. Help!
Date: Mon, 21 Dec 1992 18:35:19 GMT
Distribution: na
Organization: Hewlett-Packard Laboratories Palo Alto,CA

In article <Dec20.185657.79971@yuma.ACNS.ColoState.EDU> miker@yuma.ACNS.ColoState.EDU (Mike Riley) writes:
>... There appears 
>to be a misty coating on both the inside and outside of the corrector plate.  
>
>I'm tempted to remove the corrector plate to carefully clean it (I've cleaned
>enough Nikon lenses to know I can ruin the coating!), but I'm put off by
>the manual's warning of alignment problems.  Has anybody else experienced
>this problem, and have you cleaned/would you recommend cleaning the
>corrector plate?

According to a Celestron bulletin, the optics are rotationally matched, so
that if you take off the corrector (with secondary), you must mark its
edge and the tube so you get the rotation correct when you reassemble.
Carefully document any shim spacers between the plate and the tube, so that
you can put them back in exactly as they were to get the tilt right.


-- 
David R. Smith, HP Labs |   "I like to get my hands dirty,
dsmith@hpl.hp.com       |   because it stimulates my mind."
(415) 857-7898          |        -- Irwin Sobel
From: jcs@zoo.bt.co.uk (John C Sager)
Newsgroups: sci.astro
Subject: Re: Universal time
Date: 23 Dec 92 10:47:46 GMT
Organization: British Telecommunications plc

In article <DWELLS.92Dec17184737@fits.cv.nrao.edu>, dwells@fits.cv.nrao.edu
(Don Wells) writes:

[...]

> Precision distribution of time across the Internet has been an
> operational reality for several years, using NTP [Network Time
> Protocol]. Master ("stratum 1") servers exist in (all?) regional nets
> of the NSFnet and in most regional nets worldwide, probably including
> the UK.

There are several NTP time servers operating in the UK at stratum 1, ie
they derive their time from an external high-accuracy source. My
own machine, bear.zoo.bt.co.uk (132.146.40.28), does this normally, taking
its time reference from a GPS receiver. Its system clock is rarely
more than 50 microseconds away from UTC, and one ought to be able to
maintain millisecond accuracy from it in the UK running the latest
version of xntp3 from louie.udel.edu.
At this time, and over the Christmas period, my server is at stratum 2
as I am evaluating the navigation performance of the GPS receiver in my car.
It will be back to full accuracy in early January 1993.

John C Sager					Mail:	B67 G18, BT Labs
Email:	jcs@zoo.bt.co.uk				Martlesham Heath
Tel:	+44 473 642623					IPSWICH  IP5 7RE
Fax:	+44 473 637614					England
Newsgroups: sci.astro
From: gawne@stsci.edu
Subject: Binoculars, exit pupil size, etc...
Organization: Space Telescope Science Institute
Distribution: na
Date: Tue, 29 Dec 1992 19:44:20 GMT

Concerning the ongoing discussion of binoculars, image brightness, etc...
I went to the library and looked at the recent issue of Astronomy which
included the binocular buyer's guide.  While the guide is overall well
written it does seem to have suffered from not having been proofread by
an optics expert.  

Specifically, the guide claims that larger exit pupils (up to 7 mm)
produce brighter images.  As someone else has recently pointed out this
just is not the case.  Image brightness depends only on:

	1.  The area of the objective lenses.
	2.  The quality of the anti-reflective coatings.
	3.  The effective focal ratio of the binoculars.

The first gathers photons over a given area.  The larger that area the more
photons gathered.  The second gets as many photons as possible from the
front of the binoculars to your eyes.  The third factor (focal length) 
governs how well you'll be able to see dim extended objects, with image
brightness for extended objects dropping off as f squared.

Now a short focal ratio binocular will USUALLY also have a larger exit pupil,
so I can see how this misapplication of logic may have come about.  But let's
consider two cases:

1.  Classic 11x80 fully coated astronomical binoculars.  Here we have an
80 mm objective with 256 mm focal length (f/3.2), and a 23 mm focal length 
eyelens yeilding an actual magnification of 11.13x.  This gives an exit pupil
of 7.19 mm.

2.  10x70 fully coated binoculars.  70 mm objectives with 210 mm fl (f/3.0),
and 21 mm fl eyelenses giving actual mag of 10x.  Now the exit pupil is 
exactly 7 mm.  That's almost 0.2 mm narrower than with the longer focal 
ratio 11x80's above.

Of course if your eye can only dilate to 7 mm then the light outside that
aperture would be lost anyway.  But let's assume that your eye can dilate
that far.  Now the increased aperture of the 11x80's gives them a greater
light grasp of (80/70)**2 = 1.306, but the higher focal ratio decreases
their extend object brightness by (3.0/3.2)**2 = 0.8789.  The net effect 
is a difference in brightness of 1.306x0.8789 = 1.148.  So the larger
binoculars do gain *slightly* if your eyes dilate to 7.2 mm.  If they only
dilate to, say, 6 mm then multiply by (6/7.2)**2 = 0.69444 for the 11x80's
and by (6/7)**2 = 0.7345 for the 10x70's.  This results in the 11x80's being
only 1.085x brighter for the person with 6mm dark adapted pupils.  (Or for
that matter for ANY pupil size of 7 mm or less.)

BUT if instead of 11x80's you were to use 20x80's with a 5mm exit pupil
then the person with 6mm dark adapted pupils would see 1.56 times brighter
images than with the 10x70's!  A person with 5 mm dark adapted pupils would
see images 2.25x brighter!

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.

-Bill Gawne,  Space Telescope Science Institute
Newsgroups: sci.astro
From: clarke@acme.ucf.edu (Thomas Clarke)
Subject: Re: averting doom
Organization: University of Central Florida
Date: Wed, 30 Dec 1992 19:41:39 GMT

In article <1992Dec30.165411.25838@cs.ucf.edu> clarke@acme.ucf.edu (Thomas  
Clarke) writes:
> In article <JMC.92Dec29211051@SAIL.Stanford.EDU> jmc@SAIL.Stanford.EDU (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.
> ... In the most recent Sci Am or Sky and Telescope 

It was Sky and Telescope Feb '93 ppp 13-14.
I remembered wrong.  A one millimeter perturbation of Mars' orbit
eventually caused a 500,000 kilometer difference in the position of
Pluto after 100 million years.

Gerald Sussman and Jack Wisdom used the Supercomputer Toolkit at MIT
to simulate the solar system.

>Hey, maybe Pluto would be better than Ceres.  Kick a periodic comet
>so it ricochets of Pluto.  Pluto Ricochets off Neptune, then off Jupiter
>and into the inner solar system where it becomes tame!

A further thought:  sprinkle carbon black on the right part of the
comet and its natural outgassing will be modified.  Done properely
in an orbit or two the comet will ricochet of Jupiter then into
Pluto and away we go.  
This is a mission we could fly now!! A few hundred pounds of carbon
black in a comet fly by!  I wonder is the MIT computer is up to
predicting comet outgassing :-)

--
Thomas Clarke
Institute for Simulation and Training, University of Central FL
12424 Research Parkway, Suite 300, Orlando, FL 32826
(407)658-5030, FAX: (407)658-5059, clarke@acme.ucf.edu
Newsgroups: sci.astro,rec.radio.shortwave
From: oler@rho.uleth.ca (Cary Oler)
Subject: Daily Solar Geophysical Data Broadcast for 20 December
Organization: University of Lethbridge
Date: 21 Dec 92 20:36:42 GMT

!!BEGIN!! (1.0) S.T.D. Solar Geophysical Data Broadcast for DAY 355, 12/20/92
10.7 FLUX=148    90-AVG=137        SSN=150      BKI=1234 2232  BAI=011
BGND-XRAY=B4.9     FLU1=0.0E+00  FLU10=0.0E+00  PKI=2334 2332  PAI=012
  BOU-DEV=007,019,027,053,012,012,022,018   DEV-AVG=021 NT     SWF=00:000
 XRAY-MAX= C3.3   @ 1629UT    XRAY-MIN= B4.6   @ 0727UT   XRAY-AVG= B7.6
NEUTN-MAX= +002%  @ 2030UT   NEUTN-MIN= -002%  @ 2120UT  NEUTN-AVG= -0.4%
  PCA-MAX= +0.1DB @ 2105UT     PCA-MIN= -0.3DB @ 1950UT    PCA-AVG= -0.0DB
BOUTF-MAX=55423NT @ 0514UT   BOUTF-MIN=55392NT @ 1840UT  BOUTF-AVG=55413NT
GOES7-MAX=P:+103NT@ 1810UT   GOES7-MIN=N:-008NT@ 1027UT  G7-AVG=+071,+029,+009
GOES6-MAX=P:+124NT@ 1750UT   GOES6-MIN=E:-015NT@ 0128UT  G6-AVG=+090,-003,+037
 FLUXFCST=STD:150,150,145;SESC:150,150,145 BAI/PAI-FCST=010,010,005/010,010,010
    KFCST=2332 2223 2233 2223  27DAY-AP=028,013   27DAY-KP=5554 3433 2234 3332
 WARNINGS=
   ALERTS=
!!END-DATA!!
From: wdb3926@zeus.tamu.edu (Danny)
Newsgroups: sci.astro
Subject: Re: Jupiter's Red Spot Demo
Date: 3 Jan 1993 21:18 CST
Organization: Texas A&M University, Academic Computing Services
Distribution: world
NNTP-Posting-Host: zeus.tamu.edu
Keywords: Planets, Jupiter
News-Software: VAX/VMS VNEWS 1.41    

# I saw a demonstration on NOVA or the like that showed
# how a large rotation bucket filled with a liquid
# would produce something similar to the Red Spot of Jupiter
# on the parabolic surface of the liquid. 
# ..... 
# It seems like an ordinary dye in water would not give a 
# distinct spot.  Does anyone know what might have been used for 
# the liquid?

The dye is injected into the water after a steady state is
reached.  This allows the dark spot to be seen.

# I haven't found any info in the literature on this demo yet.

See Scientific American 258:22 May 1988 and its references.

Dan
Newsgroups: sci.astro
From: jack@feenix.metronet.com (Jack Hudler)
Subject: Re: STS-1 DISASTER/COVERUP
Organization: Tx Metronet Communications Services, Dallas Tx
Date: Wed, 23 Dec 1992 01:27:24 GMT

Clearly, too much LSD at an early age.
Newsgroups: sci.astro,rec.radio.shortwave
From: oler@rho.uleth.ca (Cary Oler)
Subject: Daily Solar Geophysical Data Broadcast for 24 December
Organization: University of Lethbridge
Date: 25 Dec 92 09:04:07 GMT

!!BEGIN!! (1.0) S.T.D. Solar Geophysical Data Broadcast for DAY 359, 12/24/92
10.7 FLUX=136.3  90-AVG=139        SSN=127      BKI=0223 2231  BAI=007
BGND-XRAY=B3.4     FLU1=9.0E+05  FLU10=1.1E+04  PKI=0223 2231  PAI=006
  BOU-DEV=004,017,011,024,015,013,027,006   DEV-AVG=014 NT     SWF=00:000
 XRAY-MAX= B6.9   @ 1301UT    XRAY-MIN= B2.9   @ 1959UT   XRAY-AVG= B3.9
NEUTN-MAX= +003%  @ 2240UT   NEUTN-MIN= -001%  @ 1600UT  NEUTN-AVG= +0.6%
  PCA-MAX= +0.1DB @ 2315UT     PCA-MIN= -0.2DB @ 1930UT    PCA-AVG= -0.0DB
BOUTF-MAX=55421NT @ 1525UT   BOUTF-MIN=55391NT @ 1906UT  BOUTF-AVG=55414NT
GOES7-MAX=P:+096NT@ 1902UT   GOES7-MIN=N:+000NT@ 1035UT  G7-AVG=+075,+029,+008
GOES6-MAX=P:+116NT@ 1902UT   GOES6-MIN=E:-011NT@ 0146UT  G6-AVG=+108,-006,+021
 FLUXFCST=STD:130,125,125;SESC:130,125,125 BAI/PAI-FCST=015,025,025/018,035,040
    KFCST=1123 4455 4455 6443  27DAY-AP=004,005   27DAY-KP=2112 2211 1122 1122
 WARNINGS=
   ALERTS=**245STRM:0708-1359UTC
!!END-DATA!!
Newsgroups: sci.astro