HDTenEightyP/NetNews huggingface dataset:
From: dj@ekcolor.ssd.kodak.com (Dave Jones)
Subject: Re: Hubble's mirror
Organization: Vonnegut Tent Rentals, Inc.
X-Newsreader: TIN [version 1.1 PL6]
Date: Tue, 10 Nov 92 15:53:30 GMT

Brian Stuart Thorn (BrianT@cup.portal.com) wrote:
> If there is a perfect mirror presumably sitting at Kodak, why doesn't NASA
> simply return Hubble to Earth and replace the faulty mirror?
>  
You want a list?  Just off the top of my head:

It would take two missions to return, fix and re-launch Hubble.  You
could probably rebuild Hubble on the ground and launch it for less.

The extended portions of Hubble are almost certainly not designed to
retract, and would have to be cut off in orbit.  This has never been
done before.

If one aspect of securing Hubble for the return mission fails, you're
screwed.  The mission would fail and Hubble would likely be disabled
permanently.

Hubble is doing valuable work right now.  Removing it from orbit, probably
for months, would damage astronomy far more than a mirror whose defects are
known and correctable by image-processing techniques.

--
||Dave Jones (dj@ekcolor.ssd.kodak.com)|Eastman Kodak Co. Rochester, NY  |
Newsgroups: sci.astro
From: F1.DAO@isumvs.iastate.edu (David Oesper)
Subject: Too Much Light At Night Causes Restlessness and Insomnia?
Organization: Iowa State University, Ames IA
Date: Wed, 11 Nov 1992 06:15:11 GMT

As an amateur astronomer for 15 years, and a backyard stargazer
since the 1960s, I have noticed a steady increase in the amount of
artificial lighting used at night.  Lights are steadily getting
brighter and brighter as more energy-efficient light systems are
developed, and there are more of them.  A disturbing trend is that
as one entity increases the light levels, so in turn do adjacent
entities.  Is the ultimate goal of all this to eradicate night?
Before you laugh, just take a look at the rapid proliferation of
outdoor lighting in your area within the last 25 years.

I love the night.  It is a beautiful part of life.  I also love a
sunshiny day.  The two compliment each other quite well, don't
you think?  I find that after a evening of observing, it is easy for
me to get to sleep -- much more so than if I have spent the evening
staring into my computer screen.

I have heard it said that high levels of light at night can cause
restlessness and insomnia.  Do any of you know of specific studies
that back up (or refute) this claim?  If it is true, that might
help explain why night crime levels in cities have continued to rise
even faster than the explosive growth in artificial lighting and
lighting levels.

David Oesper  (S Per)
Ames Area Amateur Astronomers
Ames, Iowa
Newsgroups: sci.astro
From: dyckg@wl.aecl.ca
Subject: RE: Deflecting P/S-T
Organization: AECL RESEARCH
Date: Tue, 10 Nov 1992 23:03:48 GMT

dg@cam-orl.co.uk (Dave Garnett) writes:
>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 !

Yes, it does look like you need "tonnes of force".  Isaac may have
said that  F = M.a  but I don't think that he ever got "tonnes" of
force.  8^)  So, if you really want something like "tonnes-on-the-
Earth's-surface", does the extra factor of ten (9.8) help you?  

Okay, I know, the units are still silly, but somewhere someone is
going to say, "Well, a tonne is about a ton; that's a lot of thrust!" 
Either that of they'll say, "I left that factor out on purpose,
because the  orbit is quite stable to small  radial oscillations ..."
and then _I'll_ look silly.  It'd probably be more effective to speed
it up or slow it  down or something with a big bomb.  And at as large
a distance as possible, no?  Where are those experts when you need
them?

I had to reply to this thread, since it was the first time I've ever
had a chance to save the earth.  I hope it doesn't sound like I've
tried to save it with a flame ;-)

Gary

Disclaimer:  
I am paid to know about other things, not astromomy.
No one in their right mind would pay me for what I know about astromomy.
If you know of any such person, I can be reached by e-mail at:
DYCKG@WL.AECL.CA
Xref: sparky sci.astro:11848 sci.space:15661
Newsgroups: sci.astro,sci.space
Subject: Re: Hubble's mirror
From: rivero@mdcbbs.com
Date: 9 Nov 92 12:52:22 GMT
Distribution: usa
Organization: EDS Unigraphics, Cypress CA
Nntp-Posting-User: rivero

In article <1992Nov5.145921.1405@tellab5.tellabs.com>, jcj@tellabs.com (jcj) writes:
>>...how the Hubble mirror contractor messed up the figure of the main
>>mirror.  I understand it has spherical aberration, but wonder how
>>[Rockwell?] managed to do that.
>>
> 
> Although Rockwell is my competitor in some areas, I must point out it was 
> Perkin-Elmer that blew the figuring.  
> -- 


  The error was introduced into the main mirror because the setup used to
test it was missing some spacers which were planned to locate the
test rig at the correct focal point. Because the spacers were not present,
the mirror was figured perfectly, but to the wrong focal point, outside
the range of the Hubble's focusing apperatus. This error would have shown
up had the entire telescope been tested as a whole prior to launch. Sadly, 
due to budget constraints, this was never done.



<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
|  Michael Rivero rivero@mdcbbs.com  "Middle-aged Mutant Ninja Animator" |
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|      If Thomas Jefferson were alive today, he'ld be ASSASSINATED!      |
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Newsgroups: sci.astro
From: awootten@polaris.cv.nrao.edu (Al Wootten)
Subject: Re: Elements for Swift-tuttle
Organization: National Radio Astronomy Observatory
Date: Fri, 13 Nov 1992 15:26:30 GMT

In article <BxMCvz.9Gt@rahul.net> mike@rahul.net (Mike Smithwick) writes:


   []
   What are the current elements for Swift-tuttle? I've two sets here and
   they are both missing one or two values so I can't use them.

Here are the elements from Minor Planet Circular 21081:

      MATRIX OF ORBITAL ELEMENTS
YR  MN DY  HR       J.D.           Q           E       SOMEGA     LOMEGA        I
1992 12 12  7.8  2448968.82300   .9581200   .9635900  153.00013  138.74518  113.43090
 COMET Swift-Tuttle   EPOCH Dec 4.0  ORBIT MPC 21081                             
--
+--------------------------------------------__---------+
| Alwyn  Wootten  (awootten@nrao.edu) 	     \/	GBT	|
| National Radio Astronomy Observatory        ^         |
| 520 Edgemont Road, Charlottesville, VA 22903-2475, USA|
| (804)-296-0329 voice  Let's build The Millimeter Array|
| (804)-296-0278 FAX           {>    {>    {>    {>     |
+------------------------------^-----^-----^-----^------+





Newsgroups: sci.astro
From: hbh@athena.mit.edu (Heidi Hammel)
Subject: Re: Real Men Astronomers [Was Re: e-mail activated telescope?]
Organization: Massachvsetts Institvte of Technology
Date: Thu, 12 Nov 1992 18:11:16 GMT

beaucham@astro.phy.ulaval.ca (Dominique Beauchamp) writes:
> [feats of Real Manliness deleted]
>That build character.  My country is pretty rough in the winter...

Another consideration -- besides the character and humility of the
astronomer -- is the cost of telescope time for large facilities.  At
thousands of $$$ per night of taxpayer money (in the case of the NASA
IRTF, for example), it only makes sense to make the best use of the
time, and a warm astronomer can function more effectively and efficiently
than a freezing astronomer.   IMHO, of course.

heidi
--

    Heidi B. Hammel   (hbh@astron.mit.edu)   MIT 54-416   EAPS Dept.
Newsgroups: sci.astro
From: jfbn@cbnewsl.cb.att.com (james.f.burnell)
Subject: Re: Experiences with telescope mail order
Organization: AT&T Bell Laboratories
Distribution: usa
Date: Fri, 6 Nov 1992 18:33:19 GMT
Summary: Re: Experiences with telescope mail order  

> 
> For what it's worth, I also have had some bad dealings with Pauli's (who I believe also owns
> Wholesale optics of PA).   Last Christmas I decided to buy a telescope.  So, I started to call

I know for a fact that Pauli's is not affiliated with Wholesale Optics of PA.

> I would bet that you are a lot better off buying from Adorama or Focus.  They at least
> care what their customers think about them.  This guy knew he had me, and took every
> advantage of me he could.  Buyer beware.....


I disagree, I'd stay well clear of all of these NYC outfits.

Jim Burnell
Newsgroups: sci.astro,sci.space
From: jcj@tellabs.com (jcj)
Subject: Re: Hubble's mirror
Organization: Organization?!?  You eediot!!
Distribution: usa
Date: Thu, 5 Nov 1992 14:59:21 GMT

>...how the Hubble mirror contractor messed up the figure of the main
>mirror.  I understand it has spherical aberration, but wonder how
>[Rockwell?] managed to do that.
>

Although Rockwell is my competitor in some areas, I must point out it was 
Perkin-Elmer that blew the figuring.  
-- 
		        jcj@tellabs.com
Xref: sparky sci.astro:11876 sci.space:15739
Newsgroups: sci.astro,sci.space
Subject: Re: Swift-Tuttle Comet a threat to earth?
From: harper@kauri.vuw.ac.nz (John Harper)
Date: Wed, 11 Nov 1992 20:48:57 GMT
Organization: Victoria University of Wellington

In article <1992Nov9.192334.28001@pixel.kodak.com> dj@ekcolor.ssd.kodak.com (Dave Jones) writes:
>Not quite.  Pangaea was the original supercontinent.  It split into
>Laurasia (the Canadian Laurentian Shield and East Asia together) and 
>Gondwanaland (just about everything else).

Not quite. Pangaea had a temporary existence, roughly Permian to Jurassic.
Both before and after there were varying numbers of distinct continents.
Besides the places listed above Laurasia also contained most of USA, Mexico, 
Europe (not Italy, Greece), W Asia (not Turkey, Arabia, Iran). Argument still
goes on so far as I know about which parts of Indonesia and China were Laurasia
and which were Gondwana, about when Gondwana was assembled, and about when
and whence various parts of Canada+USA in and W of the Rockies moved north 
into their present positions relative to the rest of USA+Canada.
   
John Harper Mathematics Dept. Victoria University Wellington New Zealand
From: j.jahn@abbs.hanse.de (Jost Jahn)
Newsgroups: sci.astro
Subject: Sunspots at 07.11.1992.
Reply-To: j.jahn@abbs.hanse.de
Date: 07 Nov 92 12:26:00 MET
Distribution: sci
Organization: ABBS AstroMail, D-W 2121 Dahlenburg / Germany
X-Version: ZerUU V6.45c

Sunspots at 07.11.1992., 0 h UT.

No.    Pos.  Cl.  Ar.  Mag. SF  F  M  X
---------------------------------------
7325 16S 65W Hsx   40   a    1
7326 06S 74W Hax  150   a    1
7330 08S 03E Eki  450   bg   2
7332 22S 54W Eso  140   b
7334 13N 59E Dao  190   b    7
7335 17S 63E Dao  330   b    2


No optical or x-ray flares yesterday observed.


 
--
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------------------------- for amateur astronomers ----------------------------
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From: edb@hpgrla.gr.hp.com (Ed Beshore)
Date: Wed, 4 Nov 1992 19:27:24 GMT
Subject: Re: Experiences with telescope mail order
Organization: Hewlett-Packard, Greeley, CO
Newsgroups: sci.astro

In sci.astro, pfennige@scsun.unige.ch (PFENNIGER Daniel) writes:

>I am considering purchasing a Schmidt Cassegrain telescope to one of the 
>companies advertising in Sky and Telescope.  Has anybody any advice or
>good or bad experience to share with the sci.astro group (or with me by e-mail)?

>	Thanks, 
>	Daniel Pfenniger

I just received yesterday a Meade LX200 10" SCT from Adorama.  The time in
transit was exactly 7 days and everything arrived in perfect shape.  The phone
salesmen were knowledgeable and were able to advise me on some accessories.  

The telescope arrived well collimated and appears to be 100% functional.

So far so good...

--------------------------------------------------------------
Edward Beshore                     
Hewlett Packard Company            Voice:       (303) 350-4826
700 71st Avenue                    FAX:         (303) 350-4675
Greeley Colorado, 80634            email: edb@hpgrla.gr.hp.com
--------------------------------------------------------------
Organization: Washington University, St. Louis
Date:         Thu, 05 Nov 92 12:29:24 CST
From:         Gary Kronk <C09630GK@WUVMD>
To:           NETNEWS@WUVMD
Subject:      IAU Circular backissues needed
Newsgroups:   sci.astro

While checking my inventory of IAU Circulars obtained since 1962, I
found several missed during the mid- to late 1980s. I am hoping that
someone on the net could copy the following numbers (hopefully
without reduction so I could cut them and drop them into my file
cabinet), and mail them to me.

The missing numbers are

4051 and 4052 (from 1985)
4159-4172 and 4204 (from 1986)
4296 and 4328-4336 (from 1987)

My office address is:
Gary W. Kronk
Washington University
One Brookings Drive
Campus Box 1152
St. Louis, MO   63130

I would greatly appreciate any help. Although these circulars are part
of my personal collection, they are frequently looked at by others
doing research. Although they have probably been misplaced over the
years, they are not in my office or at home. (I have checked both
places very thoroughly).

Sincerely,
Gary W. Kronk
Newsgroups: sci.astro
From: batchelor@nssdca.gsfc.nasa.gov (Dave Batchelor, Space Phys. Data Facil. 301/286-2988)
Subject: Re: Know an adjective for black holes?
Summary:  negrivesicular
News-Software: VAX/VMS VNEWS 1.41    
Keywords: black hole
Organization: NASA - Goddard Space Flight Center
Distribution: sci.astro
Date: Fri, 13 Nov 1992 19:54:00 GMT

In article <1992Nov13.162136.28824@mcshub.dcss.mcmaster.ca>, fischer@physun.physics.mcmaster.ca (Phil Fischer) writes...
>In article <12NOV199210275214@nssdca.gsfc.nasa.gov> batchelor@nssdca.gsfc.nasa.gov (Dave Batchelor, Space Phys. Data Facil. 301/286-2988) writes:
>>
>>We can always make one up.  For example, in geology, a spherical cavity in a
>>rock is known as a vesicle.  The word 'vesicle' has French origins, so we
>>could prefix it with a French word part meaning black, convert it to an
>>adjective, and voila!
>>
>>Negrivesicular: adj. pertaining to a black hole
>>------------------------------------------------------------------------------
>>Dr. Dave Batchelor   Space Science Data Operations Office   Mail Code 632
>>NASA Goddard Space Flight Center  Greenbelt  MD  20771  USA
>>batchelor@nssdca.gsfc.nasa.gov
> 
> 
>Except that the French word fro black is noire.
>-- 
>Phil Fischer                         | Hamilton, Ont.
>fischer@crocus.physics.mcmaster.ca   | Canada
>Dept. of Physics and Astronomy       | L8S 4M1
>McMaster University                  | 416-525-9140 X 4574

However, there is a French word 'negritude,' which my _Webster's New World
Dictionary_ indicates was derived from 'negre,' apparently a different French
term for black, although it may be borrowed from Spanish or Portuguese.

])ave
------------------------------------------------------------------------------
Dr. Dave Batchelor   Space Science Data Operations Office   Mail Code 632
NASA Goddard Space Flight Center  Greenbelt  MD  20771  USA
batchelor@nssdca.gsfc.nasa.gov
From: wats@scicom.AlphaCDC.COM (Bruce Watson)
Newsgroups: sci.astro
Subject: Re: Good Book for Orbit Determination...
Keywords: Not Too Shabby
Date: 10 Nov 92 19:13:43 GMT
Organization: Alpha Science Computer Network, Denver, Co.

In article <stone.721334510@cwis| stone@cwis.unomaha.edu (Travis Stone) writes:
|
|To one and all:
|
|A fairly good book on orbit determination is
|
|"Methods of Orbit Determination" by Pedro Escobal,
|New York, J. Wiley[1965].
|
|Has lots of examples, lots of exercises, and answers to some
|in the back.

I'll second that. See also his, "Methods of Astrodynamics", Wiley, NY, 1968.

But the best new one to come along is "Celestial Mechanics, A Computational
Guide for the Practitioner", Laurence G. Taff, Wiley, NY 1985. He
dispels many of the myths of orbit determination.

-- 
Bruce Watson (wats@scicom)  Tumbra, Zorkovick; Sparkula zoom krackadomando.  
Newsgroups: sci.astro
From: chaloux@mandolin.mitre.org (Dave Chaloux)
Subject: Saguaro Astronomy Club Database
Reply-To: chaloux@mandolin.mitre.org (Dave Chaloux)
Organization: The MITRE Corporation, McLean, Va
Date: Fri, 13 Nov 1992 17:04:49 GMT

For those of you who do not know, this is an excellent database of almost
every object that is visible in Uranometria. It is in DBASE III format and
any database that can deal with that format can manipulate it. It comes with
a simple report generator for the IBM.

I like this database enough that I have printed out the 152 pages of material
that extends from -42 Dec to 90 Dec and down to 16th Mag (7003 objects!).
This gives me a pretty good listing of what can be seen in my 20".
Unfortunately there are some objects that they do not have magnitudes
for that are listed as mag 99.9. If I had printed them as well it would
have been another 40 pages just for mostly nonexistant objects. I have
seen a few dozen of those objects.

A couple of the reasons I bothered to print it is that it has fields telling
you which pages in Uranometria and Sky atlas 2000 an object falls in. It also
has coordinates for the year 2000, type, class, magnitude, and size. Finally
it has a field for other names. This is great if you are hunting down
Herschel objects as it gives the Herschel designation. It has other fields
for description as well but these don't fit on my 128 column printout.

If you have an IBM computer, you might want to get this database.

Now my question.

It has an entry for PK118+2.1 at 00 07.3, + 64 58 15. It lists this as
having the alternate designation Sh 1-118. It is 12.9 Mag and 120" in
size. This is exactly the kind of object I would like to hunt down.
Unfortunately, it gives the constellation as CAM and any quick check
of a star atlas will tell you that is the wrong constellation for the
coordinates. (CAS is correct). I checked my Uranometria at those coordinates
and it is not plotted there. I also checked at 07 hours which would be in
CAM and it wasn't there either.

Could someone with the appropriate references look this up and let me
know what the story on this guy is. I am hoping CAM should be CAS and that
Uranometria simply didn't plot it.

Thanks in advance and Clear Skies (and I think I might actually have them
tonight. Its been awhile here.)
From: slayman@husc11.harvard.edu (Andrew Slayman)
Newsgroups: sci.astro
Subject: starchart programs?
Date: 10 Nov 92 20:27:40 GMT
Article-I.D.: husc3.1992Nov10.152742.17306
Organization: Harvard University Science Center


I am an archaeology student doing a little archaeoastronomy.
Nothing heavy duty. Purely observational stuff such as, "Does
this building face the summer solstice sunrise?" or "Does this
date correspond to any planetary conjunctions?" I'm also 
interested in eclipses and the like.

Do any of you know of any good, preferably cheap or free,
programs for the Mac (SE) that will tell me information 
along those lines, perhaps that will even plot out the stars
in the sky facing in a certain direction from a certain place
on earth at a certain time? I'd very much appreciate any 
info anyone could give me.

Thanks,
Andrew
Newsgroups: sci.astro,sci.space
From: pad@probitas.cs.utas.edu.au (Paul A Daniels)
Subject: Re: IS SWIFT-TUTTLE THE REAL THREAT?
Organization: University of Tasmania, Australia.
Date: Thu, 12 Nov 1992 02:23:55 GMT

In <1992Nov6.092734.1@uwovax.uwo.ca> pbrown@uwovax.uwo.ca writes:




>=========================================================================

>The Comet Swift-Tuttle saga : an addendum  - Duncan Steel, 1992 November 6th


>One thing that no-one has picked up on so far, it seems, is that it is more
>likely that an asteroid or comet big enough to wipe out mankind will hit
>the Earth before P/ST may perchance clobber us on 2126 August 14th than
>the probability of that comet itself doing the job.  That was a mouthful,
>but think about it: what I am saying is that even IF P/ST does hit the
>Earth on that date there is a chance that we may have already been hit by
>some other as-yet undiscovered object.

>A very crude estimate of the chance of P/ST hitting, a priori (that is at
>this stage without the observations to be made over the next decade) is
>about 1 in 10,000.  That is, the perihelion date is uncertain by about
>25 days, and if it does come back so as to pass its node on 2126 August 14th
>then since it takes about 3.5 minutes to cross the Earth's path and
>24 hours = 400 x 3.5 minutes, more-or-less, the probability is about 1 in
>25 x 400 = 10,000.

>However, if there are about 3,000 Earth-crossing asteroids larger than 1 km
>in size (that is about the size limit for a global catastrophe, depending upon
>mass and impact speed) and these have a mean collision probability with our
>planet of about 6 x 10^(-9) per year (see Steel & Baggaley, MNRAS, 212, 817,
>1985) then one expects one impact by such an object every ~50,000 years.
>[See also the discussion in the Spaceguard Survey report, ed. D. Morrison].
>That figure may be a little on the high (frequent) side, but I would plump
>for one per 100,000 years as being in the right ball park.

>This means that in the next century there is about a 1 in ~1,000 chance of
>a 1 km asteroid dropping in to play (havoc).  This is 10 times our current
>estimate that mankind will be stuffed by P/ST in 2126.  Note that no comets
>(either SP or LP) have been included in my sum, and these may comprise
>about 25% of the total risk (i.e. asteroids 75% of the hazard).

	Does that mean that we have a close flyby by one of these potential
killers every 10 years? I would say that there is a good case for a fair bit
of funding then..

Paul.

Newsgroups: sci.astro
From: j.jahn@abbs.hanse.de (Jost Jahn)
Newsgroups: sci.astro
Subject: Sunspots at 05.11.1992.
Date: 5 Nov 92 18:41:00 GMT
Reply-To: j.jahn@abbs.hanse.de
Distribution: sci
Organization: ABBS AstroMail, D-W 2121 Dahlenburg / Germany
X-Version: ZerUU V6.45c

Sunspots at 05.11.1992., 0 h UT.

No.    Pos.  Cl.  Ar.  Mag. SF  F  M  X
---------------------------------------
7323 16S 79W Dao  130   b
7324 16N 55W Axx    0   a
7325 16S 40W Hsx   50   a
7326 06S 48W Hax  170   a
7329 16S 01W Axx    0   a
7330 08S 31E Eao  380   b    1
7332 21S 27W Dao  130   b
7333 07N 47E Axx    0   a


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
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From: mike@rahul.net (Mike Smithwick)
Newsgroups: sci.astro
Subject: Elements for Swift-tuttle
Date: 12 Nov 92 19:59:58 GMT
Organization: a2i network

[]
What are the current elements for Swift-tuttle? I've two sets here and
they are both missing one or two values so I can't use them.

mike

-- 
"Friends don't let friends vote Democratic"

Mike Smithwick - mike@rahul.net