HDTenEightyP/NetNews huggingface dataset:
From: jdurlak@nexus.yorku.ca (Jerome Durlak)
Subject: When is first light for the mighty Keck?
Originator: jdurlak@nexus.yorku.ca
Organization: York University, Toronto, Canada
Distribution: na
Date: Fri, 11 Dec 1992 19:53:12 GMT

Although tests have been done with 9 mirror segments in place when
will 'first light' occur with all segments?

The December '92 article in Sky and Telescope - 'Keck's Giant Eye'
only mentions that 1993 will be devoted to shakedown procedures that
may last until 1994.

Is there available a comprehensive article(s)/book(s) dealing with
with design decisions, construction and instrumentation? It would
sure make a fascinating read.

Cheers,

Richard Clark

* * * * * * * * * *
If replying by email please put Richard: at the front of the subject
line as I am sharing this account. -Thanks.  
Newsgroups: sci.astro
From: metares@well.sf.ca.us (Tom Van Flandern)
Subject: Re: The Hole Story
Organization: Whole Earth 'Lectronic Link
Date: Tue, 15 Dec 1992 04:43:27 GMT


bweiner@ruhets.rutgers.edu (Benjamin Weiner) writes:

> (Note: how you gonna "communicate" with the static field?  You need
> _radiation_ to communicate, and we do agree that gravitational radiation
> can't escape a BH, right?)

     I think gravitational radiation must be one of the most poorly
understood concepts in physics.  Perhaps this only means that I don't
understand it myself.

     First, gravitational radiation == gravity waves; the terms are used
interchangeably.  So I disagree with your statement, "You need _radiation_ to
communicate."  One should be able to communicate by moving masses around
without generating any gravity waves.

     In GR, it is implicit that nothing needs to propagate to maintain the
static field.  If it did, that would cause a problem for SR, since the
experimental evidence is that any such propagation must be ftl.  In GR, it is
required that the static field around any mass pre-exists out to infinity
without detectable delay.

     Masses accelerate in response to the static fields of other masses.
Gravity waves are not the cause of this acceleration.  The acceleration
could, in principle, take place without generating any gravity waves; for
example, if the space-time medium were extremely resistant to wave
disturbances.

     Gravity waves are small ripples through space-time set off by the
acceleration of masses.  They are not to be confused with the changes of
curvature of space-time as masses move that happen without detectable delay.
If these motions set off waves also, those propagate through the medium at
the speed of light.

     Its the difference between, say, an asteroid impact and the sonic boom
which follows it.  Gravity is like the impact.  Gravity waves follow if (and
only if) the nearby medium is disturbed.  -|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: clarke@acme.ucf.edu (Thomas Clarke)
Subject: Re: The Hole Story
Organization: University of Central Florida
Date: Thu, 17 Dec 1992 14:18:35 GMT

In article <BzD2JC.GCG@well.sf.ca.us> metares@well.sf.ca.us (Tom Van Flandern)  
writes:
> 
>      First, here's what is true.  Light propagates through the solar system
> at lightspeed, taking minutes to hours to reach the planets.  When light from
> the Sun applies a force, for example, the Poynting-Robertson effect, that
> force seems to come from the Sun's retarded position, as one logically
> expects.  As a direct consequence, dust in the inner solar system slowly
> spirals into the Sun, since delayed forces are non-central forces and always
> change the angular momentum of an orbit.
> 
>      Gravity, by contrast, always appears to act from the true, instantaneous
> position of the bodies involved.  It never appears to associate with retarded
> positions.  And the Sun's gravity does not change the angular momentum of the
> planets.  By direct observation, the directions of the Sun's arriving photons
> at the Earth and the direction of its gravitational force on the Earth are
> not parallel, since one comes from the retarded position and the other from
> the true position.
> 
Are you confusing "apples" and "oranges":  Propagating waves with
stationary fields?

I suspect if the sun had a static electrostatic charge then the
electrostatic field would tend to act from the "true, instantaneous
position."  No contradiction to special relativity since the field
is unchanging and nothing is propagating.

Conversely, if the sun were radiating gravitational waves (from
micro-black holes in its core or some such) the graviational waves
would appear to come from the retarded position.   

Mathematically, I think, when you resolve a stationary field into
a superposition of progagating waves you get a summation of
retarded and advanced solutions so that action from the 
"true, instantaneous position" is kind of an artifact.  When 
something changes, only the retarded solutions propgagate and
thus radiation appears to comes from only the retarded position.  
Why only retarded solutions? - ask the philosophers :-)
--
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
From: steveh@amadeus.wr.tek.com (Steve Huss)
Newsgroups: sci.astro
Subject: 30" Dob For Sale
Date: 15 Dec 92 17:53:12 GMT
Distribution: na
Organization: Tektronix, Inc., Beaverton,  OR.



I would normally hesitate offering any thing for sale in this
newsgroup but I hope this is a valid exception:

**************************************************************************
		30" F-4 Newtonian Reflector
**************************************************************************

This is a beautiful Dobsonain made out of Maple and Walnut. It is a
truss design that travels in a very compact package. Comercial optics
that really pull in the faint fuzzies.

A friend of mine is selling this but if you have questions you can E-mail
me (I don't expect a great detail of serious inquiries). You can also 
contact him directly (I know he has prepared a video) or write for 
details:

			Steve Swaze
			700 N.E. 101st #31
			Portland Oregon
				97220

			Vocie Mail (503) 274-6016

Reason for sale: Optics too small. Steve figures he needs 40" now.
I do not have a firm asking price but I expect it to be in the 7 to 8k
range.
From: Pete_Moore@equinox.gen.nz (Pete)
Subject: Re: Daytime naked eye planet viewing
Newsgroups: sci.astro
X-Newsreader: TIN [version 1.1 PL8]
Date: 16 Dec 92 12:36:05 +1200
Organization: Equinox Networks

neely@iowasp.physics.uiowa.edu wrote:

>I have seen Venus many times
>from Iowa City, Iowa which is about 700 ft elevation above sea level
>so people at higher elevations should be able to see Venus also.

>Venus doesn't have to be at maximum brightness to see it naked
>eye in the daytime, either, although it helps if it is.

Venus is frequently visible with the naked eye during the day from here in
Christchurch New Zealand (which is effectively at sea level). In fact I saw
it yesterday afternoon at about 3pm. I find it is easier to spot if there
are a few small clouds near it (so to speak!) as this helps in focussing
one's eyes at the correct distance.

I haven't seen Jupiter or Mars in daylight, but I haven't made a serious
attempt to find either of them.
--
 +-------- pete@bignode.equinox.gen.nz  Co-sysop Equinox BBS ---------+
 | Theoretical Physicist (n): An entity whose existence is postulated |
 | in order to make the numbers balance, but who is never observed in |
 | the laboratory.                                                    |
 +--------------------------------------------------------------------+
Newsgroups: sci.astro
From: roelle@uars_mag.jhuapl.edu (Curtis Roelle)
Subject: Re: Night Lights
Organization: Johns Hopkins University
Distribution: na
Date: 11 Dec 92 21:51:55 GMT

mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:

>One idea we ought to be promoting vigorously is the use of passive
>infrared motion detectors on outside lights.

>Advantages:

>(1) Lights come on automatically when needed.
>(2) Lights are NOT on when NOT needed.  Save electricity, save money,
>     save astronomy...
>(3) Lights scare the _wits_ out of a burglar (whereas continuous
>     lighting merely helps him find his way in).

disadvantage:

(1) The next door neighbor, who's an amateur astronomer, gets drenched
with light every time he raises his arm to focus the telescope.

I guess the advantages outweigh the disadvantages! :-)
Newsgroups: sci.astro
From: olsen@vetmed.cvm.uiuc.edu (Aart_Olsen)
Subject: Re: Mirror Testing
Organization: UIUC -- Vet Med
Date: Mon, 14 Dec 1992 06:22:34 GMT

In article <Bz0p36.ux@taligent.com> Brian Drummond <drummond@taligent.com>
writes:

>Subject: Mirror Testing
>Date: Thu, 10 Dec 1992 00:23:29 GMT
>I am nearing the end of the polishing phase on my 10" f4.5 Newtonian
>mirror, and would like additional information about testing the
>figure.

>Questions: 
>
>* What are the advantages/disadvantages of using the Ronchi test over
>the Foucault test?

The Ronchi test is qualitative but easy to interpret.  You get a whole-
mirror picture and need not make zonal masks as with the Foucault test.
I think it is probably easier to get a good, zone-free surfave with a
Ronchi test, once you know what the bands are supposed to look like.

>* Can I build a Ronchi tester by easily modifying a Foucault tester?

Sure.  Same apparatus, but you replace the knife edge with the grating.

>Are there computer programs that can generate/predict Ronchi-grams
>for a given mirror?

There is a program in the Astronomical Computing column of the April 1991 
Sky and Telescope.  You input mirror parameters and the grating frequency
and location relative to center of curvature, and the program outputs
what the Ronchi bands should look like.  All you have to do it polish
until the actual mirror looks the same.  With a high frequency grating
close to the COC you can make the mirror virtually perfect.  The program
as written in the magazine is a little goofy (no need for it to be 
Monte Carlo for example--the bands look better if the whole surface of the 
mirror is scanned instead of being painted with random rays), but it 
works.

>* What is the best source for gratings?>

Edmund has them and since they're only cheap photographic film they aren't
expensive.  100 lines per inch ought to be okay.

>* What do professionals use for testing?

Null tests with precisely characterized auxiliary optics--out of the
question for most amateurs.  The last few issues of the now defunct TM 
magazine had several articles about the Ross null test.

>From the S&T ads, Willmann-Bell has several books on optics; one that
>I haven't read is "Telescope Optics" by Rutten and van Venrooij.  Can
>someone comment on this book? There appears to also be software for
>the Macintosh - does this apply to the book?

Very good book.  The software that comes with it is okay, although
not easy to use.  PC compatibles only, not Macs.
-----------------------------------------------------------------------------
Aart M. Olsen   University of Illinois at Urbana-Champaign   a-olsen@uiuc.edu
-----------------------------------------------------------------------------
Xref: sparky sci.astro:13110 sci.physics:21122
From: bweiner@ruhets.rutgers.edu (Benjamin Weiner)
Newsgroups: sci.astro,sci.physics
Subject: Re: Detecting Second-Order GR Effects in Binary Pulsars
Date: 14 Dec 92 17:15:25 GMT
Followup-To: sci.astro
Organization: Rutgers Univ., New Brunswick, N.J.

metares@well.sf.ca.us (Tom Van Flandern) writes:
>     I cited a reference to a 1992 paper which made such an argument. ...
>  ...  The point I was trying to
>emphasize is that GR without *any* gravity waves (as argued for in the Yu
>paper) is included in the set of theories still permitted by the binary
>pulsar observations.  -|Tom|-

Tom, would you repost your list of citations - it is totally impossible
to tell what you are talking about without it.  Have you ever tried to
look up a paper in a literature searcher knowing only that an author
is named Yu?
Newsgroups: sci.astro
From: rkornilo@nyx.cs.du.edu (Ryan Korniloff)
Subject: Planetary Digital Elevation Models
Organization: Nyx, Public Access Unix @ U. of Denver Math/CS dept.
Date: Sun, 20 Dec 92 06:21:09 GMT


I am looking for some FTP sites that have Digital Elevation Models (DEM)
of other planets, ie. Mars, Venus, or other moons (like Miranda, the
Unranian moon). I have already aqured the site spectrum.xerox.com but they
are all terrestrial DEMs. I'm looking for NONterrestrial..

Many thanks.


        -- Ryan Korniloff
        -- rkornilo@nyx.cs.du.edu

Newsgroups: sci.astro
From: monwel@cbnewsk.cb.att.com (douglas.w.monroe)
Subject: Meteor Showers for '93?? (was Annual calendar of celestial events)
Organization: AT&T
Distribution: usa
Date: Fri, 18 Dec 1992 17:37:33 GMT

Apparently I missed the original posting so could someone e-mail me a list
of meteor showers for 1993? I have one clipped from a report posted last 
year by wx2l@wx2l.#snj.nj.usa.na but mail to that address fails each time.
Thanks a bunch!
-- 
                                                          Doug Monroe
                   				       dwm@pruxl.att.com
  						 or   monwel@cbnewsk.att.com
Newsgroups: sci.astro
From: saseph@hal.unx.sas.com (Ed Hughes)
Subject: Re: Telescope question from rank novice
Originator: saseph@hal.unx.sas.com
Date: Fri, 18 Dec 1992 22:15:33 GMT
Distribution: na
Organization: SAS Institute Inc.


>In article <BzEvCL.HH1@unx.sas.com>, saseph@hal.unx.sas.com (Ed Hughes) writes:
>>
>> Does anyone out there know who manufactures the
>> 6" or so reflector telescope that Brookstone
>> (the gadget store) sells?  Is it one of the
>> manufacturers-to-avoid?  This thing regularly
>> sells for around $450 (but that's Brookstone
>> dollars) and is on sale now for $299.  A tripod
>> and some selection of lenses is included.  I'm
>> not sure of the type of mount, since I just read
>> the FAQ today and learned about equatorial and
>> altazimuth.
>>
>
Many thanks to all of you who replied via the newsgroup
and email!  The response was quick, educational, and--
sometimes a rarity in newsgroups--very patient and courteous.
For a number of reasons, I've decided to skip the Brookstone
'scope and look for a known brand that will serve me better
in the long run.

Thanks again to all!

--Ed
-- 
Ed Hughes, SAS Institute  | "I'm human; now shut up and pass the salt!"
Cary, NC                  | --Crow, "Rocketship X-M," MST3000
                          |
From: alfa@csource.oz.au (glenn durden)
Newsgroups: sci.astro
Subject: Re: Lunar Eclipse Dec.9 1992
Date: Sat, 12 Dec 92 11:59:38 +1100
Reply-To: alfa@csource.oz.au
Organization: Unique Computing Pty Ltd, Melbourne, Australia

andromed@cs.dal.ca (Mike Boschat) writes:

>
>  The moon is darkening at the southwestern area..2151 UT...more later..
> good observing to the others out there !!
>
>
>
>                             Clear skies
>
>                             Mike Boschat
>

So... in the end, how dark did the shadow get?   (or course, from Australia
I didnt get to see the eclipse.)
 WAs reading recently (october ASTRONOMY) about the June 14/15 eclipse, and
how the shadow was VERY dark, due to Pinatubo dust not letting any light
through our atmosphere, and so naturally wondered if things were any better
6 months later.

.........................................................
glenn durden
alfa@csource.oz.au  Unique Computing Pty Ltd, Melbourne, Australia
The opinions expressed above are that of the author only.
Newsgroups: sci.astro,rec.radio.shortwave
From: oler@rho.uleth.ca (Cary Oler)
Subject: Daily Solar Geophysical Data Broadcast for 19 December
Organization: University of Lethbridge
Date: 20 Dec 92 00:19:08 GMT

!!BEGIN!! (1.0) S.T.D. Solar Geophysical Data Broadcast for DAY 353, 12/18/92
10.7 FLUX=149.8  90-AVG=136        SSN=157      BKI=2111 1121  BAI=007
BGND-XRAY=B6.2     FLU1=1.1E+05  FLU10=9.5E+03  PKI=2112 1222  PAI=005
  BOU-DEV=012,006,008,009,21057,006,012,21536   DEV-AVG=-2861 NT     SWF=00:000
 XRAY-MAX= C1.5   @ 0443UT    XRAY-MIN= B5.8   @ 2224UT   XRAY-AVG= B7.4
NEUTN-MAX= +002%  @ 0840UT   NEUTN-MIN= -003%  @ 0450UT  NEUTN-AVG= -0.2%
  PCA-MAX= +0.1DB @ 0905UT     PCA-MIN= -0.4DB @ 1315UT    PCA-AVG= -0.0DB
BOUTF-MAX=55422NT @ 0318UT   BOUTF-MIN=55398NT @ 1815UT  BOUTF-AVG=55414NT
GOES7-MAX=P:+099NT@ 1849UT   GOES7-MIN=N:+004NT@ 0908UT  G7-AVG=+074,+037,+008
GOES6-MAX=P:+120NT@ 1847UT   GOES6-MIN=E:-010NT@ 0113UT  G6-AVG=+092,-002,+042
 FLUXFCST=STD:150,155,165;SESC:150,155,165 BAI/PAI-FCST=020,015,010/020,015,010
    KFCST=3443 3334 3333 3333  27DAY-AP=008,014   27DAY-KP=4320 0011 1124 4333
 WARNINGS=
   ALERTS=
!!END-DATA!!
From: j.jahn@abbs.hanse.de (Jost Jahn)
Newsgroups: sci.astro
Subject: Sunspots at 18.12.1992.
Reply-To: j.jahn@abbs.hanse.de
Date: 18 Dec 92 18:27:00 MET
Distribution: sci
Organization: ABBS AstroMail, D-W 2121 Dahlenburg / Germany
X-Version: ZerUU V6.45c

Sunspots at 18.12.1992., 0 h UT.

No.    Pos.  Cl.  Ar.  Mag. SF  F  M  X
---------------------------------------
7360 17S 77W Hax  120   a
7362 05S 85W Hax  140   a
7363 08S 46W Dao   70   b
7364 09N 50W Cso   60   b
7366 11S 19W Bxo   10   b
7368 32S 02W Dso   60   b
7369 06S 28E Axx    0   a
7370 08S 40E Hsx   70   a
7371 09S 37W Dao  130   b
7372 11S 69E Hsx   90   a

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.


 
--
------------------------------------------------------------------------------
ABBS AstroMail, the first and most popular German astronomical bulletin board
------------------------- for amateur astronomers ----------------------------
    + 49 5851 7896 / V.21, V.22, V.22bis, V.32, V.42, V.42bis and MNP5
    ------------------------------------------------------------------
From: palmer@sfu.ca (Leigh Palmer)
Newsgroups: sci.astro
Subject: Re: Annual calendar of celestial events
Date: 16 Dec 92 19:29:58 GMT
Organization: Simon Fraser University

In article <1992Dec16.164953.26956@cbfsb.cb.att.com>
doerfler@cbnewsf.cb.att.com (ronald.w.doerfler) writes:
>In article <7460062@hpfcso.FC.HP.COM> ajs@hpfcso.FC.HP.COM (Alan Silverstein)
writes:
>>A typical question is, "why are the sunrise/set and twilight min/max
>>dates not on the solstices?"  It is because of the "equation of time",
>>that is, the Sun runs "early" or "late" due to the ellipticity of the
>>Earth's orbit.  Of course, the solstices and equinoxes themselves drift
>>about 1/4 day later per year (versus the calendar) until we throw in a
>>leap day every fourth year to reset the calendar to them.
>
>
>In this vein, I might mention that the Dec., 1992 issue of the American
>Mathematical Monthly has a good article on the length of the day and 
>the solstices.  An even better article, in my opinion, is referenced
>in this article, and is from the same journal in 1990.  Actually, the
>older article does a much better job of deriving the effect of the 
>angle of the ecliptic to the equator, and the newer article of deriving
>the effect of the ellipticity of the earth's orbit.  It turns out that
>the ecliptic angle is the dominant effect.  If you want the actual
>equations that define the Equation of Time, these are the places to
>find them.

Did the article mention the fact, due to the same cause as the retardation
of sunrise and sunset at the winter solstice, that spring and summer in
the northern hemisphere last more than a week longer than fall and winter?
Turns out that the sun hurries through our cooler seasons, and the Earth's
rotation can't keep up with it. Kepler's second law explains it nicely.

That's my favorite counterintuitive result. It's a nice thought, since it
is snowing right now.

Leigh
From: billn@hpcvaac.cv.hp.com (bill nelson)
Newsgroups: sci.astro
Subject: Re: Planet viewing
Date: 14 Dec 92 21:43:20 GMT
Organization: Hewlett-Packard Company, Corvallis, Oregon USA

mcallist@pretzel.dsd.es.com (Steve McAllister) writes:
: In article <1992Dec10.153922.29564@siemens.co.at>, howdii@patty.gud.siemens.co.at () writes:
: |> I can not easily believe, that JUPITER can also be seen during bright daylight
: |> like VENUS, because Venus can get much more brighter then Jupiter. 

... delided ...

: Then, about 20 minutes before sunset, knowing precisely where it was in
: relation to Venus, we were finally able to spot Jupiter using fingers and
: thumbs on outstretched arms as guides, with Venus as the reference.  A
: passerby wanted to know what we were doing; so we explained, and in about three
: minutes he, too, had found first Venus, and then Jupiter.  We were able to keep
: them in sight until after sunset, when Mars was also visible.
: 
: It can be done, if everything is JUST right.  I know three people who did it.

That is not what was being discussed. If you will reread the posting, you will
see that it says "during bright daylight". That does not include close to
sunrise or sunset - no one has denied that Jupiter may be seen then - even
Mars.

Bill
Newsgroups: sci.astro
From: boroson@ucsu.Colorado.EDU (BOROSON BRAM S)
Subject: Anyone going to CV conference in Israel?
Organization: University of Colorado, Boulder
Date: Mon, 14 Dec 1992 06:18:09 GMT

Is anyone out there going to the Catacylismic Variables
conference in Eilat, Israel, Jan 10-14?  Anyone interested
in spending a few days afterward to check out the sites?
If so, send me e-mail.

Bram Boroson
boroson@ucsu.colorado.edu
Newsgroups: sci.astro
From: chris@chrism.demon.co.uk (Chris Marriott)
Subject: Re: Universal time 
Distribution: world
Organization: None
Reply-To: chris@chrism.demon.co.uk
X-Mailer: Simple NEWS 1.90 (ka9q DIS 1.19)
Date: Thu, 17 Dec 1992 19:25:41 +0000

In article <35916@sophia.inria.fr> buffet@gandalf.inria.fr writes:

>does it exist somewhere on the net a universal time server,
>and if yes, how to use it ?
>We do not need high precision. (10 -e02 second will be enough)
>
>thanks in advance
>
>-- 
>Georges Buffet:                            |
>  Chercheur CNRS, Institut de Geodynamique | phone (33) 93 95 42 60
>  Avenue Albert Einstein   Sophia-Antipolis|
>  06565 Valbonne Cedex -- FRANCE           |
>                ou
>  Projet PASTIS,  INRIA - Sophia Antipolis,| e_mail:buffet@parsifal.inria.fr
>         2004, route des Lucioles,         |  phone: (33) 93 65 78 54
>         06565 Valbonne Cedex -- FRANCE    |    Fax: (33) 93 65 77 43
>
>

I strongly suspect that getting time to an precision of 0.01s is impossible
on the Internet, given the fact the packets are dynamically routed, and two
packets sent out consecutively from the host might take totally different
routes in their journey to you, with non-predictable delays at each
routing node.  I think you'd be lucky to get the time right to within
*one* second!

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