HDTenEightyP/NetNews huggingface dataset:
From: rwmurphr@bearcat.ecn.uoknor.edu (Robert W Murphree)
Subject: Japanese X-ray satellite: Astro_D
Summary: Who has descriptions of the Astro-D Mission?
Date: Wed, 11 Nov 1992 03:49:15 GMT
Organization: Engineering Computer Network, University of Oklahoma, Norman, OK, USA
Keywords: x-ray, satellite, astronomy, japan

The Japanese scientific space agency, ISAS, is scheduled to launch
a 700 kg x-ray astronomy observatory february 3, 1993.  This
mission has as much effective collecting area as Einstein or ROSAT
and more spectral coverage though not, I understand, the resolution
of the previous two.  It continues as the fourth in a series of
Japanese x-ray astronomy satellites.  Ginga was the one before
ASTRO-D.  

Is anyone prepared to summarize this mission and provide easy 
comparisions with the capabilities and potentials for research
in ASTRO-D with Einstein and ROSAT?  Are there any articles
planned for publishing between now and february 3?  Is there
any address for public relations documents access (preferably)
in english) for ISAS or this mission?  

if anybody knows anything, I would appreciate mail and/or posting
to sci.astro
From: dg@cam-orl.co.uk (Dave Garnett)
Newsgroups: sci.astro
Subject: Deflecting P/S-T
Date: 10 Nov 92 14:54:58 GMT
Reply-To: dg@cam-orl.co.uk (Dave Garnett)
Organization: Olivetti Research Ltd, Cambridge, England

I was idly wondering how hard you would have to push
something like P/Swift-Tuttle to avoid a collision, and
came up with the following (very rough !) numbers.

If P/S-T is 10km dia, sg = 3.0, then it might mass
   1.57e15 kg

In the worst case scenario, it would head straight for
the center of the Earth, and so would require a deflection
of about 8000km to miss.

If you applied a constant thrust perpendicular to the
track for 1 year (31e6 seconds), then the acceleration
required from Newton is:-

  a = 2 . 8000 . 1000 / (31e6)^2
    = 16e-9 m/s^2

Hence the force required is = mass . accel

    = 26e6 kgf
    = 2600 tonnes !

Applying the force for longer reduces the force as the
square of the time - thus

 2 years  - 650 tonnes
 3 years  - 280 tonnes
 4 years  - 162 tonnes

If these numbers are correct (experts please !), that seems
pretty difficult to do. After all, you've got to get the
propulsion system to P/S-T, and then its got to work non-stop
for a long period. Of course the body will almost certainly
be tumbling, meaning that you can't just have one engine in
a fixed position !

People talk about light sails, but how big does a light sail
have to be to produce this kind of force at a considerable
distance from the sun ?

Perhaps the answer is to do the 'correction' on the previous
orbit, when P/S-T passes closest to the sun, and hence the
largest source of free energy ?

Dave
From: keith@cco.caltech.edu (Keith Allan Schneider)
Newsgroups: sci.astro
Subject: Re: Know an adjective for black holes?
Date: 13 Nov 1992 08:45:49 GMT
Organization: California Institute of Technology, Pasadena
NNTP-Posting-Host: punisher.caltech.edu

wa2ise@cbnewsb.cb.att.com (robert.f.casey) writes:

>"Dark"?      :-)

... or not so dark, that is the question...

keith


Newsgroups: sci.astro,sci.space
From: kentm@jec324.its.rpi.edu (Michael V. Kent)
Subject: Re: Hubble's mirror
Organization: Rensselaer Polytechnic Institute, Troy, NY
Date: Tue, 10 Nov 1992 16:26:03 GMT

In article <69203@cup.portal.com> BrianT@cup.portal.com (Brian Stuart Thorn) writes:
>If there is a perfect mirror presumably sitting at Kodak, why doesn't NASA
>simply return Hubble to Earth and replace the faulty mirror?

There is no perfect mirror sitting at Kodak.  The "mirror" at Kodak is a blank
that would need to be ground and polished at considerable expense.

>At 24,000 lbs, Hubble is well within
>the Shuttle's landing cargo capacity, and since the only part of Hubble
>likely to suffer damage during a 3g return is primary mirror (which
>will be replace anyway) I don't understand why NASA doesn't simply swap
>mirrors. NASA has already spent a fortune building COSTAR and ESA is
>building replacement (no wobble) solar panels. With three spacewalks, the
>Shuttle crew will be hard pressed to get all the work done.

The expense of grinding and polishing a new mirror from the blank and the
expense of launching two Shuttle missions (one for retrieval, another for
relaunch) is far in excess of the expense of COSTAR and one Shuttle mission.
It is also much more time-consuming, and time is science.  Meanwhile, while
Hubble is on the ground, it is doing *no* science, while considerable cutting-
edge work can be done even with the faulty mirror.  Add in the possibility
that unforseen problems may arise during retrieval, storage, and relaunch, and
the sum is that the retrieval option is costlier and riskier than the COSTAR
option.  At least that's NASA's opinion.

If the gyro's, solar panels, and COSTAR can all be fixed, then Hubble should
be back up to about 80% planned capability.  It is about 15% now.

Note to astronomers: I realize one number is not sufficient to decribe all of
the qualities of a telescope, but if these figures are true, they give a sense
of the magnitude of improvement this revisit should bring.  Hopefully all will
work as planned.

Mike

-- 
Michael Kent                                   kentm@rpi.edu
McDonnell Douglas                              Rensselaer Polytechnic Institute

Tute Screwed Aero Class of '92                              Apple II Forever !!
Newsgroups: sci.astro
From: srctran@world.std.com (Gregory Aharonian)
Subject: Know an adjective for black holes?
Organization: The World
Distribution: sci.astro
Date: Thu, 12 Nov 1992 04:38:22 GMT

   To refer to the Earth, I can use  "terrestrial".
   To refer to the stars, I can use  "stellar".
   To refer to galaxies,  I can use  "galactic".
   To refer to black holes,  what can I use?

Any suggestions would be appreciated.  Thanks.

Greg Aharonian
-- 
**************************************************************************
Greg Aharonian
Source Translation & Optimiztion
P.O. Box 404, Belmont, MA 02178
Newsgroups: sci.astro
From: ka1gt@cbnewsm.cb.att.com (robert.m.atkins)
Subject: Re: The "FK01 glass isn't transparent" ad in Sky & Tele
Organization: AT&T
Distribution: na
Date: Fri, 6 Nov 1992 22:58:56 GMT

In article <mcdonald.471@aries.scs.uiuc.edu>, mcdonald@aries.scs.uiuc.edu (J. D. McDonald) writes:
> In article <16893EB15.LINSCOT@RICEVM1.RICE.EDU> LINSCOT@RICEVM1.RICE.EDU (Stephen M. Linscott) writes:
> 
> >  There seem to be several
> >sets of numbers for FK01 floating about.  One poster said that Schott no
> >longer uses this designation.  Another poster quoted FK01 numbers from
> >a Schott catalog, which differed from the ones in the Rutten et al book.
> >Reminds me of the old adage: Believe nothing you hear or read the last
> >four months of an election year! :-)
> 
> I will repeat my previous statements, which are carefully checked and
> I stand by them:
> 
> Schott makes an "FK1" glass which is **NOT** really an ED glass, 
> and won't make a lens substantially better than plain old BK7.
> 
> Schott makes a glass "FK52" which **is** an ED glass and will make a
> very good essentially apochromatic lens with the appropriate "flint"
> glass (I forget the Schott number).
> 
> Ohara makes a glass they once called "FK01" and now call "FPL51" 
> which **IS** an ED glass and is similar but not identical to Schott FK52.
> Together with Ohara NSL33 this glass will make an truly excellent
> apochromatic lens. If I were making an apochromat, I most emphatically
> would use these glasses, especially since they are cheaper than the
> Schott glasses, give better apochromaticity, and are "normally stocked 
> items" of Ohara, whereas the Schott glasses useable for two-glass
> apochromats are "special order only". 
> 
> **NONE** of these glasses are significantly worse than plain old BK7
> in the wavelength range 350-800 nanometers. They are **all** far better
> in the UV than the Schott SF1 or SF5 usually used as the flint of a plain
> achromat.
> 
> Fluorite is better yet, but it doesn't matter. It much more expensive,
> though readily available. 
> 
> Doug McDonald


I originally brought this subject up, but I'm still confused. I am sure
Doug is correct (he knows more about this stuff than I do) and that indeed
ED objectives do not absorb appreciably more light than regular achromats.
My question is where did the info in the original Takahashi ad from
Texas Nautical Repair (?) come from? Someone else posted a reply that there
was a "FK01" glass that was only 50%/1" transmitting in the visible. Where
did that info come from? Perhaps the guys at Texas Nautical Repair (if they
were indeed the original source) made the same mistake and looked up the
wrong "FK01". So what is the source of the 50% transmitting, so called
"FK01" glass? I think the reference was to the Rutten book - but what 
was their source?
===============================================================
Bob Atkins  AT&T Bell Labs  email (direct)  att!clockwise!rma
===============================================================
From: Richard.Mathews@West.Sun.COM (Richard M. Mathews)
Newsgroups: sci.astro
Subject: Re: Lunar astronaut covers earth with thumb
Date: 12 Nov 1992 04:05:03 GMT
Organization: Sunsoft Inc., Los Angeles, CA.
NNTP-Posting-Host: astro
Originator: richard@astro.West.Sun.COM

Mark_Dakins@Novell.COM (Mark Dakins) writes:

>I have not done any serious calculation, nor any measurements but,
>I suspect from the published diameters of the Earth and Luna
>that you would need to be wearing a glove to cover the Earth
>with your thumb at arms length if you were standing on Luna.

With no more accurate measuring device than an 8.5"x11" piece of paper,
I estimated the width of my thumb to be .9" (it took 12 thumbs to make
up the 11" of the page) and the distance from eye to thumb to be about
24" (a little more than 2 pages).  These numbers indicate the angular
diameter of my thumb is 2.2+/-0.2 degrees.  The diameter of the earth
as seen from the moon is 1.92+/-0.13 degrees (depending on earth/moon
distance which varies by 14%), so my thumb probably even covers the
earth at perigee (periselene?).

    Richard M. Mathews			 Freedom for Lithuania
Richard.Mathews@West.Sun.COM		        Laisve!
From: schriber@horizon.com (Mike Schriber)
Newsgroups: sci.astro
Subject: Questions about P/Swift-Tuttle
Date: 5 Nov 92 08:16:35 GMT
Organization: Science Horizons, Inc.

First of all, in response to a previous post, I belive the /P in 
P/Swift-Tuttle designates it as a member of Perseid group (I may be
very wrong on this though, since the Perseids are a metor shower).

My questions...

Where is Swift-Tuttle visible?  What section of the sky (Coords. or
what constelation it's in) and about what time of night is it above the
horizon?

My other question is a bit more limited.  I have a program called Dance of
The Planets by ARC.  I've tracked Swift-Tuttle with this program and found
the comet to be outbound, near the orbit of Mars on 8/14/2126.  Dance of
the Planets is suposed to be a first rate orbital simulator (Gavitic forces
only) and I'm curious as to why it's so far off.  Is anyone else using this
program that can shed a little light on my mystery?

				Thanks for any and all info

				Mike Schriber


--
Mike Schriber					|  schriber@horizon.com
Science Horizons Guest Account			|  (619)755-6042 voice
Sysop:  The Dead Zone BBS/PDSE			|  (619)755-3350 BBS
WWIVnet Member System				|  1@6952 (WWIVnet Address)
From: ronnie@cisco.com (Ronnie B. Kon)
Newsgroups: sci.astro
Subject: Please Review the FAQ
Date: 13 Nov 1992 06:46:18 GMT
Organization: cisco Systems, Menlo Park, California, USA
Distribution: world
NNTP-Posting-Host: lager.cisco.com

Well, it's been on the order of a year now since I started putting
out the Amateur Telescopes FAQ, and it's doubled in size since the
beginning.  I'd appreciate it if some of you experienced types 
would re-read it and let me know if you think anything needs to
be changed.

Thanks.

				Ronnie
-- 
-------------------------------------------------------------------------------
Ronnie B. Kon          | "You couldn't deny that, even if you used both hands"
ronnie@cisco.com       |
(415) 688-4592         |                   -- The Red Queen                
Xref: sparky sci.astro:11834 sci.space:15629
From: clarke@acme.ucf.edu (Thomas Clarke)
Newsgroups: sci.astro,sci.space
Subject: Re: Hubble's mirror
Date: 10 Nov 92 16:48:59 GMT
Article-I.D.: cs.1992Nov10.164859.760
Organization: University of Central Florida

In article <1992Nov10.160238.6523@hal.com> bobp@hal.com (Bob Pendleton) writes:
> From article <69203@cup.portal.com>, by BrianT@cup.portal.com (Brian Stuart  
Thorn):
> > If there is a perfect mirror presumably sitting at Kodak, why doesn't NASA
> > simply return Hubble to Earth and replace the faulty mirror?
> 
> > Doesn't bringing Hubble home for repairs make more sense than jerry-rigging
> > and dangerous EVAs on orbit? 
> >   
> > -Brian
> 
> Depending on whose figures you believe a shuttle launch costs some
> where between $100,000,000 US and $250,000,000 US.
> 
> Repair on orbit requires 1 launch. Repair on the the ground requires 2
> launches. 
 
I know Hubble is in a high orbit, but why couldn't we combine
a Hubble retrieval with another light-payload mission like the recent
LAGEOS launch?  The Hubble could be retrieved with little extra
cost over the repair mission, but with a much higher probability
of success.

Actually, we should forget Hubble and spend the money needed
for the repair mission on building a half-dozen Keck-type telescopes. 
 
> P.P.S
> 
> Do we need nuclear weopons anymore? Or can we destroy the worlds
> economy by just defaulting on the our loans?

Paraphrasing the comedian Emo Phillips:  
	When the international bankers come to the US and ask for 
their money, we'll just have to say "Aw shucks.  We spent all the 
money on these here nuclear weapons."  
	Whereupon the bankers will say: "That's OK.  We'll just
renew your loans for another decade."


> -- 
> Bob Pendleton             | As an engineer I hate to hear:
> bobp@hal.com              |   1) You've earned an "I told you so."
> Speaking only for myself. |   2) Our customers don't do that.
>                    <<< Odin, after the well of Mimir. >>>

--
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: dsc@gemini.tmc.edu (Doug S. Caprette Bldg. 28 W191 x3892)
Subject: Re: Lunar astronaut covers earth with thumb
Organization: NASA GSFC CDP VLBI
Date: Fri, 13 Nov 1992 00:18:18 GMT

In article <1992Nov12.223805.3577@linus.mitre.org> chaloux@mandolin.mitre.org (Dave Chaloux) writes:
>Leonard Abbey writes:
>
>
>The fact the moon is only about 30' in size has some interesting implications
>for planetary observing (especially for Mars). When I go out and look at the
>full moon I can see LOTS of detail with the naked eye. In fact, I once read
>a book that recommended looking at and sketching the moon with the naked eye
>as great practice for planetary observing. Now Mars at opposition is going to
>be about 15" in diameter. This is 120x smaller than the moon. Therefore if
>we use a telescope at 120x it subtends the same angle. At least in theory a
>three or four inch (76mm to 100mm) telescope working at 120x will show a
>lot of detail on Mars as well. In reality, I think that I personally see
>more detail on the moon at those magnifications. I think I gather from this
>that the contrast of the features on the moon is higher.
>

I think the major factor here is the effect of seeing.  If the seeing limits
resolution to an arc second or so, then there is still a lot fo detail clearly
distinguishable on a 30' object, but very little on a 15" object.

>
>Still, this little bit of calculation should give hope to those with
>relatively small scopes. This also helps explain why 5 and 6 inch refractors
>are popular as planetary scopes. You do not need a huge scope to give
>good planatary views. You do need a scope that will give absolutely crisp
>views at 120x or more. A 6" refractor working at a crisp 240x is going to
>give a wonderful view of Mars with about 4 times the angular area seen as the
>moon seen with the naked eye.
>

Seeing will have a worse effect on larger scopes.  For this reason the 6" and
smaller scopes will more often approach their difraction limit under actual
conditions, than will larger scopes.  And, you are quite right in asserting that
smaller scopes can have sufficient resolution to give stupendous views of the 
planets, especially Mars at oposition.  When the seeing permits a 10" or 12.5"
scope to achieve its theoretical resolution, the result is superior. However,      
in most parts of the country, these nights are quite rare.

Of course, you can always stop down a larger scope, converting a 12.5" f/7
Newtonian to a 6" f/14 unobstucted off-axis paraboloid, for example.  You
can't stop up a smaller scope.


Newsgroups: sci.astro,sci.space
From: fischer@physun.physics.mcmaster.ca (Phil Fischer)
Subject: Re: Hubble's mirror
Organization: Dept. of Physics & Astronomy, McMaster University
Date: Tue, 10 Nov 1992 17:10:34 GMT

In article <69203@cup.portal.com> BrianT@cup.portal.com (Brian Stuart Thorn) writes:
>If there is a perfect mirror presumably sitting at Kodak, why doesn't NASA
>simply return Hubble to Earth and replace the faulty mirror?
> 

There is another wrinkle to this. Apparently the Kodak mirror is in a sealed
box which they will not allow anyone to open. Hmm? Is it possible that 
Kodak is no longer in possession of the mirror. I wonder who might have
purchased it?


-- 
Phil Fischer                         | Hamilton, Ont.
fischer@crocus.physics.mcmaster.ca   | Canada
Dept. of Physics and Astronomy       | L8S 4M1
McMaster University                  | 416-525-9140 X 4574
Xref: sparky sci.astro:11704 sci.space:15398
From: kfarmer@wsuaix.csc.wsu.edu (keith farmer;S10000)
Newsgroups: sci.astro,sci.space
Subject: Re: Swift-Tuttle Comet a threat to earth?
Date: 6 Nov 92 13:36:43 GMT
Article-I.D.: serval.1992Nov6.133643.6420
Organization: Washington State University

In article <pad.720924805@probitas> pad@probitas.cs.utas.edu.au (Paul A Daniels) writes:
>	Geologists belive that the earth originally had a super continent
>don't ask me to spell it's name. I'm just curious, could it have broken
>up due to a meteor stike?
>
>Paul.
>
If I remember correctly, Pangaea and Gwandonaland are two names fro the super-continent...

Keith
From: yerazunis@cthulu.enet.dec.com
Newsgroups: sci.astro
Subject: Re: Experiences with telescope mail order
Date: 5 Nov 92 20:31:31 GMT
Article-I.D.: engage.1992Nov5.203738.3699
Organization: Turing Police


In article <37770004@hpopd.pwd.hp.com>, stevep@hpopd.pwd.hp.com (Steve Pearce) writes...

>
> [Tale of woe about buying from Pauli's Wholesale Optics in Danbury, CT.
> deleted for brevity.]
>

I had a similar experience with them.  I got 2 grand cash out of the bank (they
like cash rather than credit cards, probably because you can't stop payment on 
cash), drove five hours, spent fifteen minutes realizing that I was being taken
and simultaneously insulted, and then drove back home with the two grand in
cash still in hand.  

I'm sad I wasted the ten hours- but glad that I never have to deal with
them again!  I'd avoid them at all costs.  Try someplace reputable, like
FC Meichner's in Boston, or Orion in CA.  Both run ads in Sky and Telescope,
I've dealt with both, and am very happy with both.

	-Bill

Copyright 1992 William S. Yerazunis (aka Crah the Merciless)
All rights reserved, no responsibility taken.

     "Time to start cutting overhead."
Newsgroups: sci.astro
From: gak@wrs.com (Richard Stueven)
Subject: Re: Lunar astronaut covers earth with thum
Reply-To: gak@wrs.com
Organization: Wind River Systems, Inc.
Date: Wed, 11 Nov 1992 22:58:20 GMT

In article 2691@mdcbbs.com, rivero@mdcbbs.com (Michael Rivero) writes:
>In article <30473@scicom.AlphaCDC.COM>, wats@scicom.AlphaCDC.COM (Bruce Watson) writes:
>|> 
>|> His unstated conclusion was that the astronaut could not have done
>|> it and you could sense his reluctance to call the astronaut a liar.
>|> 
>
>  They didn't use a naked thumb on the moon. With several layers of spacesuit
>over it, the ol' thumb does cover the Earth.

I think the caller was missing the point...Schweikart didn't say he was
impressed because his thumb was so big.

gak

---
Richard Stueven        gak@wrs.com         attmail!gakhaus!gak        107/H/3&4

        I'm always more outspoken after a few pints of Guinness.
                - Mrs. E. Slocombe

Newsgroups: sci.astro
From: p257shu@fs1.mpifr-bonn.mpg.de (Susanne Huettemeister)
Subject: Oort dead?
Organization: Max-Planck-Institut f"ur Radioastronomie
Date: Tue, 10 Nov 1992 12:52:48 GMT

We have been told by a Dutch astronomer that the famous Jan H. Oort
has died last week. Is that true? Can anyone provide details - and 
perhaps a pointer to a short biography of this man who has contributed
to almost all fields of astronomy?

Thanks!
Newsgroups: sci.astro,sci.space
From: rwmurphr@bearcat.ecn.uoknor.edu (Robert W Murphree)
Subject: Playback of Galileo Gaspara data is when?
Summary: When will the press conference be for new Gaspara data?
Date: Wed, 11 Nov 1992 04:13:43 GMT
Organization: Engineering Computer Network, University of Oklahoma, Norman, OK, USA
Keywords: galileo, gaspara, flyby 

The playback and reception on earth of the rest of the data from 
galileo's flyby of the astreroid gaspara last year is scheduled for
this month.  Assuming it takes some time to process the data for
"instant science" will there be a press release and when will it be?
From: pvtmakela@hylkn1.Helsinki.FI (M{kel{ Veikko)
Newsgroups: sci.astro
Subject: Re: MS Windows Shareware Progs via Anon. FTP
Keywords: astronomy software windows FTP
Date: 5 Nov 92 09:08:21 GMT
Organization: University of Helsinki


 MSWindows software available via anonymous-FTP from 
 ftp.funet.fi:pub/astro/pc/win:

 # DIRECTORY astro/pc/win

 aclok112.exe   I155 ASTROCLOCK - Normal and siderial time (SFX)
 alw113a.exe    I171 ASTRONOMY LAB - Sun, Moon, Planets, etc, part 1 (SFX)
 alw113b.exe    I171 ASTRONOMY LAB - Sun, Moon, Planets, etc, part 2 (SFX)
 ecu13a.exe     I165 EARTH CENTERED UNIVERSE - Star map program, part 1 (SFX)
 ecu13b.exe     I165 EARTH CENTERED UNIVERSE - Star map program, part 2 (SFX)
 globe.exe      I026 Spinning Earth
 gravity1.exe   I125 GRAVITY - Gravitation simulation (SFX)
 moontl04.exe   I123 MOONTOOL - Phases of the Moon (SFX)
 satra10.exe    I025 Satellite tracking program (SFX,WIN2)



					Veikko Makela
					(Veikko.Makela@Helsinki.FI)

					moderator of astronomy
					files in ftp.funet.fi	
Newsgroups: sci.astro