HDTenEightyP/NetNews huggingface dataset:
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Coulter Dobsonian Telescopes;  Opinions?
Organization: Hewlett-Packard Company, Corvallis, Oregon USA
Distribution: na
Date: Sat, 12 Dec 1992 10:16:09 GMT

mje@pookie.pass.wayne.edu (Michael J. Edelman) writes:
: 
: Figure on adding:
: 
: A Telrad finder
: Another 8-10x finder for the larger scopes

I threw away my normal finder scope. Actually, I gave it away. I just use
my Telrad to center the object I wish to observe, then step up through the
eyepieces. The finder scope was just getting in my way and slowing me down.

: A new foucusing mount. They provide a simple sliding mount that works well with the
: kellner eyepiece they supply, since it has a built-in helical mount, but for
: your own eyepieces you'll eventually want something better.

You can usually modify the existing eyepiece mount to be satisfactory.

: More eyepieces. The supplied kellner is, well, tolerable.

That is being generous. Kellners are only decent at around f/10 or slower.
Even a 25mm Kellner is not very good at f5.

: A proper lenscap (what do they ship with the 13" and 17"? I got a plastic showercap)

Do you mean mirror cover or diagonal cover?

: Others have replaced the mirror mounts and spiders on their as well.

Even others have kept the optics and replaced everything else.

Bill
Newsgroups: sci.astro
From: olsen@vetmed.cvm.uiuc.edu (Aart_Olsen)
Subject: Re: Testing Optics
Organization: UIUC -- Vet Med
Date: Mon, 14 Dec 1992 07:00:53 GMT

In article <1992Dec10.213517.18885@linus.mitre.org> chaloux@mandolin.mitre.org (Dave Chaloux) writes:
...
>So here is a somewhat different test that I thought might work. I know that 

Congratulations!  You've rediscovered the Hartmann test, considered to be
the best quantitative test for telescope optical systems.  In practice a
screen with holes (dozens, I think) is placed in front of the telescope
which is pointed at a bright star.  Two photographs are made, one with the
film in front of the focal plane, the other with the film behind the FP.
By measuring the location of the imaged spots on the film it is easy to
reconstruct a real-life ray trace of the optical system.  There is a
writeup of this test in one of the old ATM books.
-----------------------------------------------------------------------------
Aart M. Olsen   University of Illinois at Urbana-Champaign   a-olsen@uiuc.edu
-----------------------------------------------------------------------------
Newsgroups: sci.astro
From: sheppamj@sun.soe.clarkson.edu (Matthew Sheppard)
Subject: Automating Observatories
Organization: Clarkson University
Date: Tue, 15 Dec 1992 04:04:18 GMT

We are considering a project that would make our obervatory controlable
by remote control.

Our observatroy has recently aquired a CCD system and I cannot describe
how exciting it is taking picutres of the moon,  however sitting in the
cold for hours on end is quite taxing on the toes.

The project would entail hooking all the controls to a computer.  Such
as aiming the telescope and opening the dome.  I would greatly
appriciate any information anyone has on any work that has been done
towards this goal.  Such as controls and problems
encountered/anticipated.

I suppose the goal of the project is to be able to 'call' the
observatory over a 2400 baud phone line, open and aim the dome and then
aim the telescope and take a picutre with the CCD and then transfere the
CCD image to the controling computer.

Any information on CCD picutre compression would also be greatly
appreiciated as well as a location to obtain source code for controling
the CCD camera.

Some areas of interest:
Dome control devices
CCD control software/sources
Saftey devices (don't allow dome to open if it's raining)
Satalite picture interpretation stratagies (is it clear tonight?)

If we procede with this project I will be sure to keep you all up to
date as we anticipate many problems that we now have no idea of.


--
| Matthew Sheppard  CLARKSON UNIVERSITY  sheppamj@sun.soe.clarkson.edu |
| I'd rather have a bottle in front of me than a frontal lobotomy.ANoN |
| I don't want a pickle. DoD#477 TEP#477 RIDE FREE (8^]..etcetera..    |
Newsgroups: sci.astro
From: tmc@barnyard.syr.edu (Terry R. McConnell)
Subject: Re: Universal time 
Reply-To: tmc@barnyard.syr.edu
Organization: Syracuse University
Date: Sun, 20 Dec 92 20:13:48 EST

In article <724620341snz@chrism.demon.co.uk> chris@chrism.demon.co.uk writes:
>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:                            |

>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

Here is a question: Suppose the
time signal sent out were accompanied with a "tone", i.e., a wave packet
with known (sharply) peaked spectrum. I seem to remember dimly from
college quantum mechanics that a wave packet spreads out in time.
Could the receiving program deduce the transit time from the amount
of spread of the received tone ? 
 
This is probably either well-known or won't work. 

-- 
************************************************************************
Terry McConnell       Mathematics/215 Carnegie/Syracuse, N.Y. 13244-1150
mcconnel@rodan.acs.syr.edu                NeXTmail: tmc@barnyard.syr.edu
************************************************************************
Newsgroups: sci.astro
From: howdii@patty.gud.siemens.co.at (Wolfgang Howdii Howurek)
Subject: Planet viewing
Date: Wed, 16 Dec 1992 09:36:05 GMT
Organization: SIEMENS Austria Corp., A-1100 Wien, Gudrunstr. 11
X-Newsreader: Tin 1.1 PL5

Yes, I believe it all the way you described viewing Jupiter during daylight.
But could you tell something about viewing Jupiter on bright daylight
with naked eye? Read also Re: Daytime naked eye planet viewing in this
newsgroup!

Clear skies to all of you and me, howdii (Austria/Europe).
Newsgroups: sci.astro
From: palmer@sfu.ca (Leigh Palmer)
Subject: Re: The Hole Story
Organization: Simon Fraser University
Date: Fri, 18 Dec 1992 22:19:28 GMT

In article <1992Dec18.192414.25686@sfu.ca> palmer@sfu.ca (me) wrote:

>There is not the smallest residual anomaly
>to suggest this is not *a* correct way to look at the universe.

In conversation at lunch with a colleague I recognized that this
is an incorrect statement. Precession of the perihelion of Mercury
does, of course, constitute such an anomaly. The contrast was to
be made, not between Newtonian and Einsteinian gravity, but between
the instantaneous and retarded interpretations. Between these
alternatives the instantaneous gives results which agree with
observation and the retarded are observably wrong. While I don't
know of direct observation of orbital decay due to the Poynting-
Robertson effect I still expect the prediction is correct.

I stand by the philosophical points made after this statement. 
Their merit should not hinge upon the earlier error, since they
were not consequentially related to that statement.

Leigh
Newsgroups: sci.astro
From: kotzo@casbah.acns.nwu.edu (Nick Kotzamanis)
Subject: Buying an Amateur Telescope
Keywords: Telescope
Organization: Northwestern University, Evanston, Illinois, USA
Date: Mon, 21 Dec 1992 03:49:01 GMT

	I'm sure that you have been asked this type of question before.
I'm new on the block and I'm looking to purchase an amateur telescope and I
would like some advice from experienced users (or viewers what ever the
case may be).

	I have read the FAQ's but it did not address the
advantages/disadvantages of reflector vis refractor?  Does anyone have any
suggestions on brands/models to buy (What about vixen, it is my
understanding that they are new player on the block)?  Is there anything I
should be looking for or not looking for, which ever the case may be?

	Thanks for your time!



Nick Kotzamanis
kotzo@nwu.edu
From: FuzzyM@cup.portal.com (Paul J Mortfield)
Newsgroups: sci.astro
Subject: Re: Hi Observer
Date: Fri, 11 Dec 92 20:36:14 PST
Organization: The Portal System (TM)
Distribution: na
  <1992Dec9.144817.11414@tellab5.tellabs.com>

Sympathy, YOU want sympathy..

Yes I've seen the comet. Atleast a dozen times. HOWEVER only have been able
to take photos with the schmidt ONCE!!!!! thought I would have 4 close to 
new moon nights at thanksgiving. NOT!!! so much for SUNNY california. 
some friends were wondering if I saw the eclipse. Hell, I havent seen the SUN
all we've been getting is rain. This isnt the way winter is supposed to be.
At least I thought I could read sky & Tel, well now that it looks like
Astronomy, I dont know which mag to take to the field or the john. 
We get no respect...  
And then, even if does clear, I cant photograph down to 18th mag caus
of the Pinatubo junk. 
whats an astrophotographer to do with lousy weather.. BUILD a bigger telescope
ya thats it. I was looking at the 70inch mirror today and unfortunately its
only f/3, a little to slow for a big schmidt camera. Oh, the 70" is the
Large Amateur Telescope being built here in calif. Its now started into
fine grinding. 
This is a great way to ramble on a WET RAINY FRIDAY NIGHT. Well back to the
darkroom and print up the comet photo (2 degrees of tail)..
Hope ur weather improves...
Later Dudes...
Newsgroups: sci.astro,sci.physics
From: metares@well.sf.ca.us (Tom Van Flandern)
Subject: Re: Detecting Second-Order GR Effects in Binary Pulsars
Organization: Whole Earth 'Lectronic Link
Date: Wed, 16 Dec 1992 16:41:44 GMT


lip@s1.gov (Loren I. Petrich) writes:

> for the amount of G-wave flux to be theoretically uncertain, it is also
> required that the precession rate be theoretically uncertain, or else that
> both quantities be controllable with fudge factors that can be adjusted to
> give a line of agreement.  However, GR predicts an unambiguous value for
> _both_ the precession rate _and_ the G-wave decay rate.

     Not exactly, Loren.  The GR prediction of the "precession" rate (what I
call the periastron rate) depends upon masses, semi-major axis, and
eccentricity too.  When you drop the G-wave flux to zero, for example, the
masses and elements adjust so that the periastron rate fully takes up the
slack.  That's what Damour's statement means when he says that the amount of
gravitational radiation cannot be uniquely solved for by itself.  It can only
be constrained by theory.  -|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: tholen@galileo.ifa.hawaii.edu (Dave Tholen)
Subject: Re: Galileo, Ida and Gaspra
Organization: Institute for Astronomy, Hawaii
Date: Sun, 13 Dec 1992 07:25:09 GMT

In article <92345.101226K3032E0@ALIJKU11.BITNET> K3032E0@ALIJKU11.BITNET writes:

> Is "Galileo" still scheduled to approach the minor planet "Ida" on August 28,
> 1993?

Yes.

> Is there a special star-catalogue for astrometric work on this minor
> planet in preperation of the flyby (like the "Lick-Gaspra"-catalogue for the
> first asteroid-flyby)?

Yes.

> Have new pictures of "Gaspra", played back during the near-earth-passage of
> "Galileo", been published?

Not to my knowledge.
From: roelle@uars_mag.jhuapl.edu (Curtis Roelle)
Newsgroups: sci.astro
Subject: Which Lunar Eclipse Was Darker?  Dec 82 or 92?
Summary: Two Dark Lunar Eclipses Within 10 Years Thanks to Volcanos
Date: 11 Dec 92 22:14:49 GMT
Organization: Johns Hopkins University

Unfortunately, during the lunar eclipse I was in class except for a 10
minute break at 23:05 UT (so I got to view 2nd contact) when I bolted
outside with a pair of 7x35's, and when class ended near 0 UT (so
resumed observing at 3rd contact and the following partial).  I did
not get to view the eclipse during its maximum.  Now,

Gerry Santoro - CAC/PSU <GMS@psuvm.psu.edu> writes:

>Egad!  What a night for astronomy!

>After a 2-month cloudy spell the sky miraculously cleared this afternoon
>over central PA in time for the lunar eclipse.  In fact, as I watch out
>my window the moon is just coming out of the darkest eclipse I have seen
>in 30 years of watching.  To the naked eye it darn near completely
>disappeared.

>In 10x50 binoculars it was a dusky grey-black at mid eclipse and was
>only barely visible at 40x in a 2.4" refractor.   My 8" F6 Newtonian
>showed it as a beautiful faint grey, with only the slightest hint of
>deep brown along the southern edge.

Although I only saw it near 2nd and 3rd contact, the moon remained
visible to the naked eye as a brownish-grey, and quite faint.  But I
seem to remember that the eclipse 10 years ago, on 30 December 1982
was even darker yet.  That eclipse came several months after the
eruption of Mexico's El Chichon volcano.  After totality in 1982 I
could *not* see the moon with the naked eye and also found it impossible
to focus a camera connected to on a 6-inch Newtonian.

Granted, the 1982 eclipse was before dawn on the East Coast, and at a
lower altitute -- I think the moon set before 4th contact.  But it was
just as clear, if not clearer than during Wednesday's eclipse.  
Also I viewed the 1982 eclipse from a darker site.

So sci.astro readers, which was darker?  The December 1982 or the
December 1992 eclipse?

Curt
From: reinhard@stsci.edu
Newsgroups: sci.astro
Subject: Re: astronomy question
Date: 15 Dec 92 14:30:50 GMT
Distribution: world,na
Organization: Space Telescope Science Institute

In article <SNOW.92Dec14184811@castor.hahnemann.edu>, snow@castor.hahnemann.edu (Donald C. Snow) writes:
> 
> Can someone help with the following?
> 
> A netless friend has asked me to post the following question. Reply to
> me (I don't read this group, and I doubt anyone else is interested), and
> I'll pass on the answer to them.
> 
> What position on the earth (in latitude, to the minute, and longitude,
> to the minute) would satisfy the following two conditions:
> 
> 1) the time is Sept 23, 1987, 11:33 and 34 seconds, GMT
> 
> and
> 
> 2) Vega is directly overhead.
> 
> 
> Thanks!
> 
> 
> -- 
> =======================================================================
> Donald C. Snow         || snow@castor.hahnemann.edu    ||
> Senior Systems Analyst || snow@hal.hahnemann.edu       ||            
> Radiation Oncology     ||        (and)                 ||      	    
> Hahnemann University   || gaston@drycas.club.cc.cmu.edu||      	    
> =======================================================================
> 								    


This sounds like an astronomy homework problem that someone can not solve.

Is it?

Kent Reinhard
Space Telescope Science Institute
Newsgroups: sci.astro
From: paul.burnett@pcs.sj.ca.us (Paul Burnett) 
Newsgroups: sci.astro
Subject: SKY AND TELESCOPE
Date: 12 Dec 92 06:53:00 GMT
Distribution: world
Organization: PCS-BBS - San Jose, CA - 408-270-4085
Reply-To: paul.burnett@pcs.sj.ca.us (Paul Burnett) 

TO: jhouser@vax.cns.muskingum.edu

J>                i am taking a survey on the new look of SKY 6 TELESCOPE
 >magazine .   so please PLEASE  send me your opinon about it

J>         whats good ?  whats bad?  how to change it?

S&T is (or used to be...) a _working_ journal - you would find it in the
workshop, or outdoors wherever telescopes are found.  Now it appears to
be a yuppie coffee-table accessory.

---
 . QMPro 1.0 41-8688 . ...from San Jose, CA
From: steinly@topaz.ucsc.edu (Steinn Sigurdsson)
Newsgroups: sci.astro
Subject: Re: The Hole Story
Date: 21 Dec 92 03:36:19 GMT
	<BzKJy0.355@well.sf.ca.us>
Organization: Lick Observatory/UCO
NNTP-Posting-Host: topaz.ucsc.edu
In-reply-to: metares@well.sf.ca.us's message of Sun, 20 Dec 1992 17:44:24 GMT

In article <BzKJy0.355@well.sf.ca.us> metares@well.sf.ca.us (Tom Van Flandern) writes:

Tom is right that the gravitational force seen by the Earth from the
Sun is towards the "current" position of the Sun, not the retarded
position. See for example LPPT 12.4 or MTW 18.4 or 39.9 I don't think
he's right that this is a problem for GR, calculating motions using
retarded potentials does work, it's simply very cumbersome because the
first few post-Newtownian terms vanish. In GR gravity acts towards the
geodesically propagated "current" position - and you can consider this
an example of geodesic motion being the natural "uniform motion" under
gravity (cf comparable uniform motion problem in electrostatics).
The question of what happens to non-gravitational rearrangement of
matter and how the effective force propagates is in general an
unsolved problem because you have to self-consistently specify the
arrangement on non-gravitational stress-energy and take into account
it's back reaction on the metric.

	We have been discussing that very point in another thread about the
   binary pulsar.  A few GR specialists have an opposite opinion to yours; for
   example, the 1992 paper by Yu cited in the other thread insists that there is
   no wave solution for Einstein's equations.

I suppose I should read the paper, but there are exact solution of
plane gravitational waves for GR. They're literal solution of the
Einstein equation. (they're also pathological in some sense but
that's a different issue (eg colliding waves give singular solution,
QM types might want to think of the four-point graviton vertex
for analogy)). The gravitational waves claimed for pulsars and
other detectable sources are deduced from a perturbative formalism
but it's a fairly robust solution.

Let's build LIGO and find out!

*  Steinn Sigurdsson   			Lick Observatory      	*
*  steinly@lick.ucsc.edu		"standard disclaimer"  	*
*  The laws of gravity are very,very strict			*
*  And you're just bending them for your own benefit - B.B. 1988*
From: paul.burnett@pcs.sj.ca.us (Paul Burnett)
Newsgroups: sci.astro
Subject: I want the Moon.
Date: 13 Dec 92 15:45:00 GMT
Reply-To: paul.burnett@pcs.sj.ca.us (Paul Burnett)
Organization: PCS-BBS - San Jose, CA - 408-270-4085

TO: jeremy@jacobs.CS.ORST.EDU

JS>     I'm looking for a clear, bright graphic of a full moon - no
  >shadows, eclipses, umbras penumbras, phases.  I've archied moon and
  >fullmoon and there are many neat pictures but most of the full moon
  >shots show <75%.

Do you have UUDECODE capability?  If so I can send you a 320x200 GIF
(do you have GIF-viewing capability?) right here in a message.

---
 . QMPro 1.0 41-8688 . ...from San Jose, CA
From: newberry@kepler.as.arizona.edu (Mike Newberry)
Newsgroups: sci.astro
Subject: Re: Sky & Tel e-mail address requested
Date: 11 Dec 92 01:27:02 GMT
Organization: University of Arizona, Tucson, AZ

In article <1992Dec10.081926.18590@ncrcae.ColumbiaSC.NCR.COM> greg@korg3.columbiasc.ncr.com (Greg Porr) writes:
>In article <1992Dec9.221704.14726@sfu.ca> palmer@sfu.ca (Leigh Palmer) writes:
>>I saw a posting here implying Sky & Telescope could be contacted by e-mail.
>
>Their address is skytel@cfa.harvard.edu - I sent them my comments on the
>new format yesterday, and had a reply back in about 20 minutes from
>Rick Fienberg.
>
>It wasn't until last night when I looked at S&T's staff list in the January
>issue that I realized that he's the President of Sky Publishing Corporation.
                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>I think we're talking to the right people!
>
>-- Greg Porr
>   (Greg.Porr@ColumbiaSC.NCR.COM)

Good, now we know who to blame.
Newsgroups: sci.astro
From: clarke@acme.ucf.edu (Thomas Clarke)
Subject: Re: The Hole Story
Organization: University of Central Florida
Date: Fri, 18 Dec 1992 16:28:39 GMT

In article <1992Dec17.202617.1121@sfu.ca> palmer@sfu.ca (Leigh Palmer) writes:
> In article <1992Dec17.141835.1510@cs.ucf.edu> clarke@acme.ucf.edu (Thomas
> Clarke) writes:
> 
> >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....
> 
> This is, perhaps, the most extreme possible denial of what used to
> be considered desirable in physical theory; it was called "elegance".
> You are proposing to discard this simple, static field because it
> seems to you to be an ad hoc add-on to a wave theory, but you are
> willing to acknowledge another bit of really ugly ad-hocery in the 
> very same paragraph:
> 
You misunderstand my point entirely.  When properly handled, the
elegant physical theory deals directly with stationary fields and gives
the correct answer.  You can decompose the stationary field into
the summation of propagating solutions, like a Fourier decomposition.
The apparent retarded and advanced features of the propagating
solutions involved in the Foureir sum all cancel out, giving the 
same result as the elegant theory.  

The Fourier analysis is really just a formal device, sometimes 
computationally convenient.   Most everyone agrees that what is 
really going on is the elegant physics.  If Ptolemy had had
Fourier theory he could have saved appearances with an infinite
series of nested epicycles.  But I am not saying that this would
have meant that a theory using infinitely nested epicycles was true.

> >                                                      ...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 :-)
> 
> For heaven's sake, take off your blinders!
> 
This was an allusion to a poorly remembered book (Davies?) 
that discussed incoming and outgoing (advanced and retarded) 
electromagnetic waves from an accelerated charge in terms of
time's arrow, our apparent perception of an asymetry in time.  
--
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: cain@geomag.gly.fsu.edu (Joe Cain)
Subject: The Universe and everything
Summary: please, not 42 again.
Organization: Florida State University Geology Dept.
Date: Sat, 19 Dec 92 03:11:15 GMT


Several of us novices have asked the question as to the relation
between the Hubble constant and the age of the Universe. The obvious
answer is of course 1/H with H converted from km/sec/megaparsecs to gigayears.
However, this implies a constant rate of expansion and with H=60 is
embarressingly small comapared to the estimated ages of some of the
distant objects if you include any acceleration. 

There was a report on NPR this morning that the results of the recent
cosmological conference in Berkely solved all problems. Or at least
apparently Hawking was reported to have conclusively decided that the
question of the dark matter was solved, the universe did not have a
beginning, but the big crunch will be on us in only about 10
gigayears.

would anyone like to clarify what really came from this conference? 

 

Joseph Cain		cain@geomag.gly.fsu.edu
cain@fsu.bitnet		scri::cain
Department of Geology B-160
Florida State University
Newsgroups: sci.astro.hubble