HDTenEightyP/NetNews huggingface dataset:
From: jhouser@vax.cns.muskingum.edu
Newsgroups: sci.astro
Subject: WANTED : COMET SWIFT-TUTTLE COORDINATES
Date: 10 Jan 93 13:45:46 -0500
Organization: Muskingum College

fellow astronomers

      Does anyone have COMET SWIFT-TUTTLE coordinates for the restof the month?


      please reply to .....
  
          jhouser@vax.muskingum.edu



thanks

jim

Newsgroups: sci.astro
From: willson@seas.gwu.edu (Stephen R. Willson)
Subject: Perseid Shower Peak?
Keywords: meteor
Organization: George Washington University
Date: Sat, 9 Jan 1993 02:06:05 GMT

When is the Perseid shower supposed to peak this year?  What kind of
frequency could one expect to see?  The only time I went out to watch a
shower, I saw about four in one hour.

-- 
-----------------------+-------------------------------------------------------
 Stephen R. Willson    | A fitting end to a screwy campaign year...
 willson@seas.gwu.edu  | Here to swear in the President of the United States,
 (202) 395-4922        | Larry King!                         -The Miami Herald
Newsgroups: sci.astro
From: greg@korg3.columbiasc.ncr.com (Greg Porr)
Subject: Re: Super Polaris vs. Classic C8?
Organization: NCR Corp, MCPD-Columbia, Columbia, SC
Date: Mon, 11 Jan 93 22:17:01 GMT

In article <1550033@hplvec.LVLD.HP.COM> calloway@hplvec.LVLD.HP.COM (Frank Calloway) writes:
>The fork-mounted C8s have setting circles that are *much* larger
>and easier to read than those on the Super Polaris mount.  If the
>use of setting circles to locate objects is important to you, the
>C8 on the fork mounting may be desirable.

There's something else you should know about the Super Polaris setting
circles.  The Right Ascension circle does not travel with the drive,
so it needs to be re-aligned with an object whose R.A. is known, each time
you want to move to a new coordinate.

I don't have one (I have the Powerstar C8), but the owner's manual gives
instructions for all the scopes, so that's how I found this out.

-- Greg Porr
   (Greg.Porr@ColumbiaSC.NCR.COM)
Xref: sparky sci.astro:13781 sci.physics:22351
From: carlip@landau.ucdavis.edu (Steve Carlip)
Newsgroups: sci.astro,sci.physics
Subject: Re: That Great Pulsar Timing Flame War
Date: 9 Jan 93 00:37:31 GMT
Followup-To: sci.astro
Organization: Physics, UC Davis

In article <1993Jan7.085151.13461@nuscc.nus.sg> scip2124@nusunix1.nus.sg (MARC PAUL JOREF VAN LOO) writes:

>  There exists no decent derivation of the
>  gravitational radiation of a binary pulsar.
>  Yu's objection to this derivation is correct.
>  But I found out recently that it is not new:
>  Read the 16th lecture of Buchwald's book
>  17 simple lectures on GR. (1982).

Lecture 15, probably.  Buchdahl argues --- rather convincingly, I
think --- that the linear approximation "at best...might be taken
as a heuristic guide," for several reasons:
(1) it treats the motion of the sources inconsistently (the paths are
approximated as Keplerian, while actually they should be independent
straight lines at this order of approximation);
(2) fields are strong inside the sources, so the linear approximation
is not valid everywhere;
(3) it has not been shown that the linear approximation is the first
term in a convergent series, and, if so, what the characteristics of
the full series are; and
(4) it has not been shown that higher order corrections are small.
He calls for a mathematically sound rederivation of the radiation
formula ("which abandons any appeal to naive linearization on the one
hand and to energy complexes on the other and which, in fact, avoids
any redundant reference to `radiation' altogether").  He then adds
that some recent (as of 1981) work has made progress in this
direction.

These strike me as fair criticisms, although there will always be
argument about exactly how mathematically rigorous a result must be
before it is believable.  Remember, though, that considerable
progress has been made in the past eleven years.  

In particular, the "post-Minkowskian algorithm" of Damour and 
collaborators goes a considerable way towards meeting these 
objections: it provides a systematic expansion in which higher
order terms can be compared to lower order terms, and it treats
the motion of sources consistently.  Furthermore, Damour and
Schmidt have shown that this approximation is "reliable"  ---
that is, that it is at least locally an expansion of an exact
solution of the field equations  (see J. Math. Physics 31 (1990)
2441) --- and they have made some progress toward extending their
local results to global ones.

There is certainly work that remains to be done in this area.  In
particular, as I understand it, there are still difficulties in
giving a realistic treatment of compact sources.  There's no doubt
that there is still room for surprises; but my own guess is that
if you're looking for surprises in "established" physics, this
isn't your best bet.

(The journal with Yu's article is at the bindery, so I haven't
been able to read it yet; does it make an argument qualitatively
different from Buchdahl's?)

Steve Carlip
carlip@dirac.ucdavis.edu
From: stevep@hpscit.sc.hp.com ()
Newsgroups: sci.astro
Subject: Re: Mt. Palomar Info Needed
Date: 5 Jan 1993 15:47:08 GMT
Organization: SSG/CSY Pinewood, UK
Distribution: world
NNTP-Posting-Host: hpopdlcm.pwd.hp.com

In article <5JAN199309475881@ariel.lerc.nasa.gov>, aavso@ariel.lerc.nasa.gov (Tom Quesinberry) writes:
|> I need some information concerning Mt. Palomar Observatory.
|> 
|> Does anyone know if there are tours of the 200 inch during 
|> the day? Is there an E-mail address I can out other information?
|> 
|> Thanks in advance.
|> 
|> 				Tom Q.

About 3 years ago I visited Mt. Palomar. The 200 inch "tour" was simply
viewing the inside of the dome from a windowed gallery. I don't remember there
being any formal tour as such.

-- 
=======================================================================
!!             Steve Pearce		Hewlett-Packard              !!
!!					SSG/CSY Pinewood, UK	     !!	
=======================================================================
Newsgroups: sci.astro
From: bw@TorreyPinesCA.ncr.com (Bruce White 3807)
Subject: Re: Mt. Palomar Info Needed
Organization: NCR (Torrey Pines Development Center)
Disclaimer: This posting does not necessarily reflect the opinions of NCR.
Date: Wed, 6 Jan 93 18:26:20 GMT

In the past, the Oceanside Photo Telescope Club has been able to 
arrange to have a tour of the scope for club members.
--- Bruce

Newsgroups: sci.astro
From: Ben Burch <Burch_Ben@wes.mot.com>
Subject: Super Polaris vs. Classic C8?
Organization: Motorola, Inc.
Date: Thu, 7 Jan 1993 11:12:00 GMT
X-Xxmessage-Id: <A771C0B3F001B081@ben_burch.pb.wes.mot.com>
X-Useragent: Nuntius v1.1.1d16
X-Xxdate: Thu, 7 Jan 93 05:12:51 GMT

Hello!  I am still telescope shopping.  I was looking over the Celestron
fliers, and was wondering what, other than the obvious movement of the
observing position and the need to adjust the counterweight, is the
downside (if any) of the Super Polaris version of the Celestron C8?
Is the mounting stable?  Is it suitable for long-exposure photography?
Is the drive mechanism clean?  Thanks!

-Ben Burch
From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
Subject: Re: Averting doom
Summary: Appropriately named vulcanologist
Organization: AI Programs, University of Georgia, Athens
Date: Wed, 6 Jan 1993 05:40:01 GMT

In article <JMC.92Dec26004848@SAIL.Stanford.EDU> jmc@cs.Stanford.EDU writes:
...
>     years... and a BILLION years after that, the planet will
>     look more like dusty volcanic Venus.
>	     Ken Caldeira and James Kasting calculated the
                 ^^^^^^^^
                  volcano expert, I presume?   :)



-- 
:-  Michael A. Covington     internet mcovingt@uga.cc.uga.edu :    *****
:-  Artificial Intelligence Programs       phone 706 542-0358 :  *********
:-  The University of Georgia                fax 706 542-0349 :   *  *  *
:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **
Newsgroups: sci.astro,sci.physics
From: kopfj@bert.Tymnet.COM (John Kopf,D,6305)
Newsgroups: sci.astro
Subject: Re: Algorithms for determining dimension of a set of points
Date: 12 Jan 93 21:55:57 GMT
Reply-To: kopfj@bert.Tymnet.COM
Organization: Sun Microsystems


As I recall, 3 points define a plane, except in the degenerate case of a line.

so, your program would print 2 *except* in the case where Xa/Xb = Xa/Xc for *all*
X = <X, Y, Z> (and points a, b, and c).

is this what you're asking for?

JK
From: grizbud@grizila.pillar.com  (Jim Gorges)
Newsgroups: sci.astro
Subject: Re: wormholes
Date: Sat, 09 Jan 93 00:26:09 CST
Organization: Grizila Onenode Network

ags@seaman.cc.purdue.edu (Dave Seaman) writes:

> f_markwort@ccsvax.sfasu.edu writes:

> > OK, we might as well get this over with.  I imagine the net will be  
> swim-
> > ming with wormhole questions after the new Star Trek episode.  So, what
> > are they, are they real, can do travel in space-time using them, and  
> 
> Wormholes are not new to the Star Trek universe, having appeared in one of  
> the motion pictures (the first one, I think). Wormholes are mathematically  
> possible, but there is no particular evidence to suggest that they are  
> anything more than that. A wormhole would indeed allow matter to be  
> transported between fixed points in space-time. I suppose the chances of  
> surviving such a trip are probably comparable to the chances of surviving  
> after having your molecules disassembled and reassembled in a transporter  
> beam.

Less than one week ago I finished trying to read "Cosmic Wormholes: the
search for interstellar shortcuts" by Paul Halpern.

Now, I'm basically a bonehead when it comes to understanding things
theoretically and technically advanced and "indistinguishable from
magic."  So, grad students and postdocs, what's the judgement on
Halpern's explanations and physics?  Is the book worth the attention of
someone desiring to be introduced to the concepts and theories, or
should it be used to keep the computer desk from wobbling?  Inquiring
minds want to know.....





--
Jim Gorges <grizbud@grizila.pillar.com>         | Life is a series of
GENIE: J.GORGES                                 | adjustments.
Fidonet: jim.gorges@p15.f34.n147.z1.fidonet.org | (Michael J. Carney - 1985)
Newsgroups: sci.astro
From: dierick@brsux0.bro.dec.com (Dierick Dominique)
Subject: Re: 127ED Meade Refrators: Info Please
Reply-To: dierick@ketje.enet.dec.com
Organization: Digital Equipment Corporation, Brussels
Distribution: na
Date: Mon, 11 Jan 1993 12:15:43 GMT


In article <1993Jan8.183702.6168@Newbridge.COM>, alberts@Newbridge.COM (Albert Saikaley) writes:
>Newsgroups: sci.astro
>From: alberts@Newbridge.COM (Albert Saikaley)
>Subject: 127ED Meade Refrators: Info Please
>
>I am interested in purchasing a Meade 5" apochromatic refractor (127ED).  I had
>an 8" SCT.  I would like the following info:
>
>i)  does anyone have any hands on experience with the 127ED, if so 
>please send any comments on performance.
>ii) what difference in performance will I notice over my old  8" SCT.
>
>-- 
>Albert Saikaley                        Voice: (613) 591-3600 
>Newbridge Networks Corporation         FAX  : (613) 591-3680
>600 March Road, P.O.Box 13600, Kanata, Ontario, Canada K2K 2E6
>

Me too ...
I am looking to buy a 7 inch ED, but I'd really like first to see some
results with it ( photographs of deep-sky and planets ) to compare the
refractor with the higher priced EDT from AstroPhysics. 
Any comments and experiences welcome. I know the 3 lens design probably
is better, but is it worth the nearly double price you have to pay for it ?

Dominique
Newsgroups: sci.astro
From: mcdonald@aries.scs.uiuc.edu (J. D. McDonald)
Subject: Re: Diffraction question (was Re: obstructed view?)
Organization: UIUC SCS
Date: Wed, 13 Jan 1993 02:33:40 GMT
Keywords: telescope refractor reflector

In article <C0rp00.9q2@news.cso.uiuc.edu> dnash@uxa.cso.uiuc.edu (Dave Nash) writes:

>In article <1993Jan12.224443.1547@linus.mitre.org> chaloux@mandolin.mitre.org (Dave Chaloux) writes:

>>An images of a star in focus consists of an Airy Disk and diffraction rings
>>around that disk. An unobstructed telescope like a refractor can, if it is
>>perfectly made put about 84% of the light into the central disk. Any obstruction
>>(or under or over correction of the optics) puts more of the light into the
>>diffraction rings.

>...

>>The answer isn't this simple however. Obstructed reflectors of larger diameter
>>can be gotten for much less money than equivalent refractors. If the reflector
>>is well made, the larger diameter of the mirror can more than make up for the
>>loss of the light due to the obstruction. Doug McDonald has said on numerous
>>occasions on the Net that given perfect optics, a Reflector of size a and
>>with an obstruction of size b will perform as well as a refractor of size
>>a - b/2. 

Caveat:  I'm saying that this applies to fine details on planetary disks.
Not to looking for the companion of Sirius or Deimos or Phobos.


>This reminds me of a (possibly naive) question I have on this topic:

>Some people use this argument (obstructions causing more light in the
>diffraction pattern to be in the outer rings) to argue that small refractors
>have an intrinsic advantage over significantly larger reflectors.
>Is it possible for a larger, obstructed scope to be largely immune to
>this effect (more light in the rings) on the diffraction pattern, when
>compared to a smaller, unobstructed telescope, like a refractor?
>True, obstructed scopes dump more light into the rings, but the diffraction
>pattern of a large scope is so much smaller that this would seem to have no 
>real effect -- especially if the larger scope is sufficiently larger that
>the diameter of its first diffraction ring is less than that of the Airy
>disk alone of the smaller scope.  Is this reasonable?


>I'm not an optics jock, so i'll yield to those who are.

That's about right. I've got the calculations right here (i.e. 50 feet from
the present poster's office) in Mathcad.

It seems that a twice-size SCT is better at all distances away from the
central star than a perfect refractor. Come look. Actually it is far better
than that.

Again, we assume perfect optics.

Doug McDonald
From: J.JAHN@ABBS.zer.sub.org
Newsgroups: sci.astro
Distribution: world
Subject: Sunspots at 12.01.1993.
Date: 12 Jan 93 19:54:00 +0100
X-Gateway: ZCONNECT AB ABBS.hanse.de [UUCPfZ V3.8a U004]

Sunspots at 12.01.1993., 0 h UT.

No.    Pos.  Cl.  Ar.  Mag. SF  F  M  X
---------------------------------------
7386 05S 64W Hsx   90   a
7389 20S 46W Bxo   10   b
7391 12S 12W Cso   40   b    1
7394 16S 59W Dso  120   b    2
7395 13N 07E Bxo   10   b
7396 13S 25W Axx    0   a
7398 07N 03E Dso   60   b
7399 07N 12W Cro   30   b    3


No optical or x-ray flares yesterday observed.
From: jcurtis@seqp4.sequoia.com (John Curtis)
Newsgroups: sci.astro
Subject: polishing, when is enough?
Summary: help
Keywords: ATM, mirror polishing
Date: 4 Jan 93 18:26:57 GMT
Distribution: usa
Organization: Sequoia Systems Inc., Marlboro, Mass.


Hi.

I'm dragged my 8" mirror out last night (long in the making).
Did about one hour of polishing using cerium oxide on a 
opthalmic polishing lap (polishing pads stuck to the original tool
per a S&T article.)

Things seem to be going well.  The only exception is a small 
scratch (this long: --- ) which I am choosing to ignore.

Total polishing time is just under 4 hours, and the mirror looks
reasonably bright, but not as bright as a wet mirror.

The claim is that this opthalmic lap will polish 2-3 times faster than 
a pitch lap.

When is enough?  Any hints?   I haven't used my Foucault apparatus on
this guy yet.  I did look at the surface at 30x using a Rat Shack
hand microscope and was shocked to see a pebbled surface.  This 
may be underneath the actual top surface of the glass.  The lap 
did start polishing the whole  surface immediately.

Please help me over my novice angst.

Ciao,

jcurtis at sequoia.com
Organization: Washington University, St. Louis
Date:         Sat, 09 Jan 93 00:32:46 CST
From:         Gary Kronk <C09630GK@WUVMD>
To:           NETNEWS@WUVMD
Subject:      Re: Perseid storms 1993/1862?
Newsgroups:   sci.astro

On Fri, 8 Jan 1993 02:47:53 GMT T.Ryan and D.Moore, Astronomy Ireland,
P.O.Box 2888, Dublin 1, Ireland wrote the following.

>We are looking for information to help get some idea of what to expect with
>regard to the Perseid meteor storm predicted for August 1993. We presume that
>the comet's return to perihelion in 1862 (what date was perihelion?) should
>have caused storm levels also, particularly given its close approach of 32
>million miles, but no one seems to have seen anything. In his 1988 book
"Meteor
>Showers", Gary Kronk, only refers to good rates (up to 215/hour, not really
>storm rates) in 1861 and 1863 (no rates are given for 1862).

The comet passed perihelion on August 23, 1862. There actually was activity
reported on August 10, 1862 by the Japanese. They claimed, "Stars fell like
a shower at midnight." Some astronomers have categorized this observation as
a "storm," but no meaningful figures can be derived.

>Was there a Full Moon on Aug. 9 1862 i.e. was moonlight the problem?

Yes. Full moon occurred on August 9, 1862, at 21:23 UT.

>Did the comet and Earth's orbits not cross as closely as they do now?

The orbit of the comet has changed surprisingly little during the last 2000
years according to the computations furnished by Brian G. Marsden which
link the comet to Chinese comets appearing in 188 and -68. Meteors showers
would still be expected.

>Could it be that as the storm only lasts about 1 hour, an unpopulated part of
>the dark side of the Earth was facing into the radiant (or poor weather)?

Bingo! The nature of the "storm" would be an extremely narrow spike. If it
occurs over a nonpopulated area or an area experiencing cloudy skies, the
"storm" would easily be missed.


I have done much more detailed studies of the Perseids, especially of the
possible storms reported by the Chinese and Japanese during the last 2000
years which usually occurred decades before or after the comet reached
its perihelion, but the information above should directly answer most of
your questions.

Sincerely,
Gary W. Kronk
From: joseph.o'neil@homebase.com (Joseph O'Neil) 
Newsgroups: sci.astro
Subject: Re: Sct vs. newtonian
Date: 8 Jan 93 18:42:00 GMT
Distribution: world
Organization: Home Base BBS - St. Thomas, Ontario - 519-633-7253
Reply-To: joseph.o'neil@homebase.com (Joseph O'Neil) 

 -=> Quoting Agnew@gems.vcu.edu to All <=-


 Ag> Dear Netpeople..
 Ag> One of our Neurosurgeons asked me about the new Meade economy
 Ag> Newtonians, and how they'd stack up against an sct... 
 Ag> (schmidt-cassegrain) 
 Ag> Any takers???  Jim Agnew

  You get what you pay for.  I think the Meade newtonians are good value for
the money.  They are simple, and lck many features of the SCT type telescope,
but this is not a bad thing.  I've ssen to many poeple go all out getting
every gadget under the sun then becomming overwhelmed by thier equipment.
   From a personal perspective, amatuer astronomers with the simplest, most beat
up equipment seem to be the ones who actually do spend a lot of time
observing.
     Joe




... Back up my hard disk? I can't find the reverse switch!
--- Blue Wave/QWK v2.10
                                                                                    
Newsgroups: sci.astro
From: alberts@Newbridge.COM (Albert Saikaley)
Subject: 127ED Meade Refrators: Info Please
Organization: Newbridge Networks Corporation
Distribution: na
Date: Fri, 8 Jan 1993 18:37:02 GMT

I am interested in purchasing a Meade 5" apochromatic refractor (127ED).  I had
an 8" SCT.  I would like the following info:

i)  does anyone have any hands on experience with the 127ED, if so 
please send any comments on performance.
ii) what difference in performance will I notice over my old  8" SCT.

-- 
Albert Saikaley                        Voice: (613) 591-3600 
Newbridge Networks Corporation         FAX  : (613) 591-3680
600 March Road, P.O.Box 13600, Kanata, Ontario, Canada K2K 2E6
Newsgroups: sci.astro
From: bunner@vms.macc.wisc.edu (Dana A. Bunner)
Subject: Re: are fixed focus binoc's any good for astronomy??
Organization:  University of Wisconsin Academic Computing Center
Date:  7 JAN 93 14:42:45    

In article <1993Jan7.090516.70@ccu1.aukuni.ac.nz>, timothy@ccu1.aukuni.ac.nz (Tim Bates) writes...

>My question is, are fixed focus binoculars any use for star gazing. 

You are going to have to test them.  If you have 20/20 eyesight then possibly
yes.  If you wear eyeglasses then it is highly unlikely they have sufficient
eye relief ... which you may be able to deal with ... and it is quite
unlikely you will be able to use them without your glasses.  Every 
recommendation I've ever read was against using them for astronomical use
but it would seem to me that given the right parameters, they might be a 
passable, low-cost alternative for casual use.  Bear in mind that they
probably aren't top quality optics and have minimal lense coatings.

Most are designed to be low-cost, easy to use, hunting binoculars.  So they
aren't designed for night use or sharp pin-point images. 

Dana Bunner
Newsgroups: sci.astro,sci.geo.geology,alt.sci.planetary
From: cain@geomag.gly.fsu.edu (Joe Cain)
Subject: Re: History of Earth/Moon system
Followup-To: sci.astro
Summary: looking for summary
Organization: Florida State University Geology Dept.
Date: Wed, 6 Jan 93 15:53:11 GMT

        Does anyone have a reference for the present best estimates on
the distance of the Moon from the Earth in geologic time and its
present rate of recession? I recently read a figure of 4 cm/year, but
recall having read 3 cm/year previously. Also, I note that Wagner
writes in "Introduction to the Solar System" that projections indicate
the distance would increase to 550,800 km in 50 billion years with a
tidally locked Earth rotation rate of 47 days. Unless I am off a
factor of 10 (always possible) (550,800-384,000)x1E5/(50E9)= 0.3
cm/year.

        I have also read that the Earth day was like 11 hours 2 Ga
ago, and 22 h at about 400 Ma. No estimates seem printed as to the
distance of the Moon from the Earth in earlier times, though Press and
Sevier write in their "Earth" that the closeness of the Moon in the
Earth's very early evolution would have accelerated outgassing of
volatiles due to large tidal effects (heating?). Also, is there any
significance to the 10ish hour rate being close to that of Jupiter and
Saturn? (i.e. is there some theory that would guide the initial
rotation rate of material accreted in the original nebula, perhaps as
a function of distance from the Sun?).

        I assume that the tidal recession rate must be strongly
dependent on a number of factors, including distance. Is there a
theory that illustrates such changes?




Joseph Cain		cain@geomag.gly.fsu.edu   
cain@fsu.bitnet		scri::cain
(904) 644-4014		FAX (904) 644-4214 or -0098
From: bweiner@ruhets.rutgers.edu (Benjamin Weiner)
Newsgroups: sci.astro,sci.space,sci.physics
Subject: Re: averting doom
Date: 8 Jan 93 20:28:14 GMT
Followup-To: sci.astro
Organization: Rutgers Univ., New Brunswick, N.J.

bhoughto@sedona.intel.com (Blair P. Houghton) writes:

>>>	     WASHINGTON (UPI) -- Life on Earth as we know it will
>>>     come to an end in 1,500 million years ...

>Do you seriously believe that a species capable of creating
>and enjoying The Love Boat is capable also of learning
>galactic engineering?

A better question in my opinion is whether a species capable of
creating and enjoying The Love Boat *should* be saved from doom.
From: ralph.buttigieg@f635.n713.z3.fido.zeta.org.au (Ralph Buttigieg)
Newsgroups: sci.astro
Subject: Lunar Eclipse 4 Jun 93
Organization: Fidonet. Gate admin is fido@socs.uts.edu.au
Date: 03 Jan 93 08:36:08 GMT

G'day
As some of you may be aware there will be a total eclipse onf the moon
visible in Australia on 4-6-93. I intend to encourage people in my astronomy
club to observe it and at least make Danjon scale measurements. Is anyone
interested in the results? Have the results of the December eclipse been
published yet?
ta
Ralph

--- Maximus 2.01wb
 * Origin: Vulcan's World-Sydney Australia 02 635-1204 (3:713/635)