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We mentioned this a couple days ago, but this time around there's pictures!

"There's" is a contraction for "there is". But, because the word "pictures" is plural, you'll want "there are". Bite the bullet and just spell it out. Also, "couple" isn't a true adjective. You need the "of" in "couple of days". So, the corrected version is:

We mentioned this a couple of days ago, but this time around there are pictures!

If you're wondering, I'm an EE with an English Minor who has written a few parsers, and lack of standards compliance pisses me off!

The loss of Mt. Stromlo Observatory facility is very great loss.

A number of the obvious sites related to Stromlo are down, due to the fire or due to the wide spread power outages in the area. I will make links to indirect and cached pages.

Established in 1924, the Commonwealth Observatory at Mount Stromlo, on the outskirts of Canberra. Commonwealth Observatory was recognized for its important research into the origin and future of the universe.

Astronomers at Mount Stromlo made outstanding contributions to astronomy. It would be difficult to list all of the important contributions to Astronomy made by the people working at Mt. Stromlo. Now, a few come to mind:

• Stromlo research in the 1950s provided the first clue that the Magellanic Clouds had evolved differently from our own galaxy. These results gave us important insights into galactic evolution.
• In the 1990's, astronomers from Stromlo and Sliding Springs (many km away from the fire area) showed that about 90% of disc galaxies (such as our own) are greatly influenced by ''dark matter'', in their galaxies' halos.
• They made important observations in the first hours after Supernova 1987A (the first naked eye supernova in several centuries of years) was discovered.
• Then there is the sort of work such as the Stromlo Abell Cluster Supernova Search
• The Massive Compact Halo Objects (Macho project that was the first to record many microlensing events in our Galaxy as well as in the LMC.
• Then there was all of that tedious, but vital work of spectral classification of southern stars.
• Many of the first parallax distances to Southern stars were first made at Stromlo.
• The list goes on and on ... I am sorry that I must leave out so many other significant contributions!

One of the principal instruments at Stromlo was the 74-inch (188-cm) reflecting telescope. The 74-inch telescope was erected in 1953, and until the completion in 1974 of the 3.9m Anglo-Australian Telescope at Siding Spring, this was the largest telescope in the Southern Hemisphere. In 1982, it was used to discover the fossil star CD-38245: a star so old that it is made almost purely of gases left over from the big bang.

It also was home scopes such as the robotic 50-inch (127-cm). It was an excellent example of how an older telescope could be outfitted with new controls and instruments to perform innovative work. The MACHO project was conducted on the 50 inch.

Two historical scopes come to mind, the Oddie, and the Yale-Columbia telescope:

The Oddie, was a wonderful 9-inch Newtonian telescope. The Victorian MP, James Oddie, presented this telescope to the Commonwealth government for use in the proposed Commonwealth Observatory. It was installed on the site at "Mt Strom" (as Stromlo was originally known) in September 1911. Over the years the Oddie telescope has made valuable contributions to Southern Hemisphere astronomy; it did some of the first measurements of the brightness, color and spectral classification of southern stars.

The Yale-Columbia telescope, 26-inch Grubb long-focus refractor was erected at this site for the determination of parallaxes of southern stars (it was the largest refractor in the southern hemisphere when first installed.

Moreover, there were other scopes as well ... But alas, from what can be seen from the air at this time, most, if not all of those telescopes have been lost. At appears that heat from the burning of the nearby bush /trees was hot enough to melt many of the domes at the observatory.

The Canberra Astronomical Society used the Stromlo lecture hall for their monthly meetings. During public nights, the public had access to a domed C14 scope, the Oddie, and a number of scopes brought to the site by members ... all through the hard work and generous efforts of the Canberra Astronomical Society.

I had the privilege of observing at Mt Stromlo several times and spoke at one of the CAS meetings. I still can recall flying down from the US to a CAS member's home to see SN1987, . I was there only 36 hours after the naked eye supernova was first observed. I still recall seeing the single star, at a distance of over 168,000 light-years, change in color and rightness over the course of an evening. I was one of the most important astronomical events I have had the honor to witness. I recall that every scope up at Mt Stromlo was all pointed at the Large Magellanic Could where SN 1987A was blazing away. The previous observing board schedule was cancelled as people raced to collect as much early critical data as they could in the early hours of the event.

I had the privilege of being with the members of the Canberra Astronomical Society on two of my several total solar eclipses: 1991 in Hawaii, US and most recently the 2001 eclipse in Ceduna, AU.

(Both trips count among my several successful viewings of solar totality. Although the 1991 Hawaii was a close call that was saved because my friend (the one who introduced me to the CAS) broke his arm a very short time before the Eclipse ... which allowed both of us to have a full view of Totality in Hawaii ... but that is another story!)

My best wishes and heart felt sorrow go out to all of those people who worked so hard to make Mt. Stromlo such a wonderful place for the public to visit and who helped the observatory make many important contributions to Astronomy. Much of what was lost cannot be replaced. Still it is my hope that those who are left will be able to rebuild something anew out this tragedy.

Paper lasts thousands of years!

Not unless it's Permanent Paper. Most of the paper made since the 1850's is acidic and will disintegrate within centuries (if not decades.) See Brittle Books: What's the Deal? for more info. Too bad, really. I prefer books myself.

Plasmoids involve hurling clouds of energized atomic nuclei and electrons into the path of incoming warheads. There was also the idea of the HEL/CPB combo. A laser ionizes a channel in the atmosphere for the charged beam to travel along to the target. However, charged beams bend and are thus useless. One last idea was based on the Advanced Test Accelerator research at the Lawrence Livermore Laboratory. They had created a form of artificial lightning from pulses of electrons, which may have had SDI applications if it could be made to fire thousands of miles precisely instead of several feet randomly.

Research on Teaching Math with Direct Instruction

Direct Instruction with Readying

http://www-hoover.stanford.edu/research/conference s/22497.html

Doug Carnine is working with the President to get quality teaching techniques to teachers. None of these techniques need computers to teach.

I have seen a film where the creator of Direct Instruction took 5 year old kids from inner city Chicago, all black and labeled as needing special ed, and he had them doing algebra.

I didn't learn this kind of algebra till I was in 9th grade, and these little kids were answering questions on a black board in their heads. (like figuring out the hypotenus (sp) of a right triangle) and they were all excited and raising their hands saying "I know, I know!"

Of course the reason Direct Instruction hasn't made it into mainstream education, despite the incredible wealth of data and research showing it works better than every other system used today, is because it puts the resposibility for children learning in the teachers lap.

There is no excuses for teachers if the kids don't learn with DI, because kids _can_ learn and it's been shown to work with the slowest learners.

Our current systems allow teachers to say "well the kid didn't learn because the kid [enter excuse here]" (excuses range from "the kids has ADD" to "the kid didn't pay attention in class") which always ends up with the result "it's the kids fault the kid didn't learn".

Some interesting things to read about DI.
http://www.adihome.org/esp/v17n3/letters.pdf
http://www.adihome.org/esp/v17n3/index.html

-v

Research on Teaching Math with Direct Instruction

Direct Instruction with Readying

http://www-hoover.stanford.edu/research/conference s/22497.html

Doug Carnine is working with the President to get quality teaching techniques to teachers. None of these techniques need computers to teach.

I have seen a film where the creator of Direct Instruction took 5 year old kids from inner city Chicago, all black and labeled as needing special ed, and he had them doing algebra.

I didn't learn this kind of algebra till I was in 9th grade, and these little kids were answering questions on a black board in their heads. (like figuring out the hypotenus (sp) of a right triangle) and they were all excited and raising their hands saying "I know, I know!"

Of course the reason Direct Instruction hasn't made it into mainstream education, despite the incredible wealth of data and research showing it works better than every other system used today, is because it puts the resposibility for children learning in the teachers lap.

There is no excuses for teachers if the kids don't learn with DI, because kids _can_ learn and it's been shown to work with the slowest learners.

Our current systems allow teachers to say "well the kid didn't learn because the kid [enter excuse here]" (excuses range from "the kids has ADD" to "the kid didn't pay attention in class") which always ends up with the result "it's the kids fault the kid didn't learn".

Some interesting things to read about DI.
http://www.adihome.org/esp/v17n3/letters.pdf
http://www.adihome.org/esp/v17n3/index.html

-v

Doesn't "Google" use as a verb dilute its trademark value? (Something like that happened to Xerox).

Who cares about hydrogen? Why not base everything off of the most basic unit possible: the planck length, time, and mass, and consequently the planck energy and every other unit. Just find some arbitrary number by which to multiply the units to some practical range (something base-10 is obvious, but maybe there is some more mathematically profound multiple, like pi, which would be more useful), and you have an entire system of measurement.

counterprogramming - noun - to use...

You cannot usefully project the current growth trend very far. First, energy consumption in 2000 averaged 1.3e13W. Assume that energy consumption doubles every 50 years, which is a growth of around 1.4% a year. Then in 1000 years energy use is about a million (2^20) times as large, or 1.3e19W. The energy received by Earth from the Sun is around 2e17W. The temperature of the Earth would have to increase a lot in order to radiate all that waste heat away.

Now jump to just 10000 years, when energy consumption has increased 1.6E60 times to 2e79W. The Sun outputs somewhere around 4e26W. 5e46 new stars will have to be acquired.

Talking about millions of years just gets absurd. The historic trend will have to change.

It's in the Samba configuration. It's something like "OS Level" and it will be set to some number, like maybe 50.

This number is how MS machines determine who is the Primary Domain Controller, basically the one with the highest OS level gets it, unless things are specifically configured otherwise. IIRC, Windows NT 4 has an OS level in the low 30s. Newer versions of Windows have higher OS levels, and server versions have higher levels than workstation or desktop versions.

So, all you have to do is use SWAT, or otherwise edit smb.conf, and set your OS level to some low number, like 1.

This site is a good introduction with lots of useful tips. If you really need to know Samba, though, I highly recomend this book.

Of course, if they come to the University of Oregon they can come to at least one of the comptuer labs and use WordPerfect (since we have WP, MSOffice, and OO.o on our computers in the lab I work at).

Myself, I love WordPerfect. Every time a user comes in with some unknown error in Word, I scream for Reveal Codes...

I haven't used xdvi myself, but if you use dvipdf, you can view your documents with preview.app which comes with OS X. Yes, it's one more step (but if you use BibTeX, and references, and the other cool LaTeX stuff, you have to do a few steps before you even get a dvi, so it's not that much more work).

Also there is a packaged called TeXshop which runs dvipdf and previews the PDF document, but personally I've never got the pdf previewer on it to work (and I prefer to use emacs to write my documents)

this is the really cool stuff here: http://opticb.uoregon.edu/~mosswww/memory/shm.html .... yeah baby! can't wait till we can fit our entire music collection on one storage cube.

-eek

There used to be a theory of gravity, it is now the law of gravity. It has been proven. It has been observed many times. Gee even the folks in east Tennessee call it Newton's 2nd law. And in Oregon. And in Winnepeg. Or do a Google search.

So you are saying that you have proof of the three items you mentioned? Would you please post them for our education? But number 2 is not evolution, it is adaptation and that is totally different and can't be used to prove number 1 (see my previous post concerning the wallabys, they are still wallabys). I am not sure that number 3 can be used to prove number 1 either. There are very good arguements against DNA proving evolution. The fossil record could be misintrepreted, just as the length of time in the earth's creation is being misintrepreted. And morphology is simply studying change which is another way of saying adaptation (using big words to hide the truth).

No, I haven't seen a species or a universe being created. But I also don't refer to it as a theory (nor as a law). It is simply fact and has been declared since the beginning. The "theory of creationism" was created by scientist attempting to drag creation down to the same level as evolution.

I don't hear voices in my head, and I have never heard voices in my head. And you called me a very poor troll.

Quick lesson in physics for those that don't want to read the article...

Time travel. Possible? Yes. It happens relativly speaking every day.

When you get onto an airplane you slow down in time. To say this simply. The faster you go, the slower time moves around you. This was confirmed back in the 1970's using atomic clocks. Although this isn't exactly time travel it's called time dilation which is a product of the general theory of relativity.

A quick little reference for those not familar with Relativity is a set of lecture notes from a basic astronomy class in U of Oregon.

For a little more in depth reading I'd look into buying The Large Scale Structure of Space-Time by Stephen W. Hawking. Or for those that are sadistic you can read Quantum Field Theory in Curved Spacetime and Black Hole Thermodynamics. That is a collection of lectures from the University of Chicago. Although good in a sense of understanding relativity it kinda takes a tagent into the debate about light being a particle or a wave argument.

If you do all the math it turns out there are 5 stable Lagrange points, two of which even allow a stable orbit around it.

the sun is pulling, the Earth and moon and other objects are constantly pulling," said Martin Lo of NASA's Jet Propulsion Laboratory in Pasadena, California.

"Our theory has refined to the point where we can actually compute these trajectories

Oh good grief. Wind? Solar? These things have been "up and coming" for YEARS and they have never been successful.

First, wind power generation requires massive farms of windmills. Not picturesque little ones here and there like in the Netherlands. We're talking tall stalky turbines covering hundreds of acres. Resistance to building wind farms on a proper scale has been nothing short of monumental. Furthermore, working on them is dangerous, and turbines have required frequent maintenance. Finally, the Greenies don't like them because they've been known to kill birds. This page includes a formula for generating power out of a wind turbine. If 100% efficiency is assumed, and assume a turbine that has blades 100 feet long operating in a 15 mile per hour wind, we find that this turbine will generate 519.5 kW. Plant Votgle, a nuclear power facility in Georgia, has a combined output of 2430 MW (2430 million watts). We'd need almost 4700 windmills to equal the power output of Plant Votgle.

Solar power. What happens when it is cloudy? Or Dark? I don't know anyone that would volunteer to only have electricity only on sunny days. Furthermore, it has the same scale problems as wind. According to this page, the average incident solar power density is 164 watts per square meter. At 100% efficiency, a solar plant would have a collector surface area of 14.82e6 square meters to equal Plant Votgle's power output (that's a square a little less than four kilometers on a side). A chart on this page says that efficiency for collectors used to heat water is between 60 and 80%, increasing our required collector size even more.

The energy density of solar or wind is not nearly high enough to replace fossil or nuclear fuels for electricity production on a large scale.

There's a good chance that Wolfram is attempting to do much more than provide support for the work of others (although that is certain to occur). The sheer number of axioms, the amount of supporting "data", and the numerous instructions to build supporting "instruments" (via his software) leads me to that conclusion.

Thomas Kuhn proposed that mainstream science is based on an ongoing process of shattering and creating scientific worldviews. I would say that that the most meaningful work is performed by people who are able to support a new theory with new data and cause a paradigm shift.

Copernicus, using the latest instruments and the latest data acquired from those instruments, argued that it is the Sun at the center of the solar system (and not the Earth as most scientists in his era argued). I think that Wolfram is trying to be a Copernicus as opposed to a Hawking. So the real question here is: what is Wolfram getting at with this book? Well, he probably is not done yet.

On a lighter note, we can't blame such talented (and often obsessed) individuals for perceiving everything within the context of their paradigm - especially when it could lead to more software sales ;)

By adulthood, Mendeleev's periodic table of the elements is firmly planted in a typical mind either as a tool for study or proof of mystical forces at work in nature. There are alternative structures: some clever and others using alternate media, extensions to the table providing nuclear structure, fermi surfaces, and line spectra.

Still others are extraordinarily cross-thematic, merging chemistry with comic books, poetry or haiku. But only the grouping-nature of the columns is retained in rejected elements, condiments and beer. Eventually the elements and the periodic qualities have been lost entirely, reducing the periodic table to a design template for topical lists of funk and rock music, comedy and TV shows, famous mathematicians and presidents, even SGI products. Soon a complete breakdown of the scientific aspect yields no similarity to the original, becoming a glorified table, a marketing tool, or hype itself. There is mounting evidence of a conspiracy.

So, what are they supposed to use, a really big passwd file? OpenLDAP? Novell NDS? A big Oracle database? Why should we even care what the technology is, as long as it works?

Maybe because it doesn't work.

ever thought of that?

Unfortunately, all the Microsoft-hating government pawns around here seem to have missed the real point of the article.

This isn't just "Microsoft-Hating"
These are valid concerns...

Yeah, because at less than .10 cent per *kilo*watt hour and, umm, 24*30, uhh, 720 hours per month, let's see, err, that's 216000 wats used, max, AKA 216 kilowatts, well, uhh. Hmph. That's a whopping 21.6 cents per month. Good gracious, time to get that second job working nights, or maybe just recycle a few aluminum cans to finance such an astronomical power bill. :)

average cost of electricity in US as of 1999

That said, I've got about 5 computers and matching monitors (there's where the power's eaten up) running 24x7, and totally understand the desire to keep power use down... :)

unlikely.

Newer versions of Internet Explorer also support "Web Proxy Auto-Discovery Protocol". They look for a machine called "wpad" in their domain, and get proxy settings from it. That's even easier to set up, and shouldn't require any client configuration.

How should the ISP give users an option to disable this? Would they have to phone tech support, or maybe fill out a web form? Would the decision to stop proxying have to be approved by someone?

Normally I'd have no problem going through a proxy (I might disable the proxy for certain dynamic sites, which is easy if you're using Junkbuster). But if the proxy is down, or slow, I'd like to turn it off, without calling tech support (I'll wait on hold for 30 minute, the first support person won't have a clue what a "transparent proxy" is, the next person will tell me they're not authorized to disable it, I'll wait on hold some more, speak to a manager, ...). And using a web site to disable the proxy wouldn't work too well if port 80 stopped working.

We also have every possible option we've ever encountered acted out somewhere in some universe by at least one of our other selves. Unlike the traveler facing a fork in the road in Robert Frost's poem "The Road Not Taken," who is "sorry that I could not travel both / And be one traveler," we take all the roads in our lives. This has some unsettling consequences and could explain why Deutsch is reluctant to venture from his house.

All potential energy on earth is either the result of past accumulation and storage of solar energy (fossil fuel, biomass, etc.) or the consequence of the structural creation itself (nuclear, geothermal, etc.). All of these stored energy reserves will run out, some much sooner than others; almost certainly the ones we're using most and most cheaply first.

Once they're gone the earth, if it's still livable after all the biomass ever acculated is loosed into the atmosphere, will operate in steady state where the energy available is the energy incident on it (or nearby).

Might as well start learning to live within 164 watts/sq meter now.

I did that, but it locked up HARD. That's because the code from the ports drm-kmod and the ports xf86 had some mismatch. This should probably work with XF86 4.2.0. Take a look here. The maintainer confirmed it too.

This is especially interesting
It's even more interesting when you spell it right.

Oh, this is slashdot, nevermind.

What's new about this is that an entire course is being dedicated to them.

I think it may have a colour (but see below for why it may not). The wave-particle duality says that the photon has a wave associated with it, and that wave has a frequency given by dividing the energy of the photon by Plank's Constant (E=hf, or f=E/h) Whether it actually has a colour will surely depend on what that frequency is. If it is ouside the visable part of the e-m spectrum, it has no colour, in the same way that, for example, a radio wave has no colour.

Are they referring to the Heisenberg Uncertainty Principle? What is the law of indeterminacy??

1. cats have souls (meaning they consistently break down quantum phenomena by observation, or something like that)
   AND
   
2. the cat is alive

Umm, yes
Although, I will say being able to run Doom on anything simply rules. It's one of my favorite games of all time. I remember typing in the code for my TI-85 (cuz I broke my uplink when I dropped it) and playing it in Math class. I wish those things had IR ports for LAN parties. I wonder if someone would be able to somehow port it into a Lego Mindstorms hack?

Got any links, faqs or suggestions on how to do this? Thanks!

Try here, here, or here for information and links on SSH tunneling. The second one (on uoregon.edu) actually covers doing it for e-mail.

• Formation of complex organic molecules
• Self-replicating systems
• Protein synthesis; DNA is the genetic material, but it requires proteins to replicate
• Compartmentalization: the first cell

• Nucleosynthesis in stars to form complex molecules
• molecular clouds
• A very significant fraction of the Earth' s carbon came from extensive cometary bombardment on the primitive Earth

As for natural processes that lead to temperatures below the cosmis microwave background temperature, there are at least of couple of obvious answers to that. One answer is that the CMB temperature is not exactly the same depending on which direction in the sky one measures. So if you consider the CMB temperature to be a single number, then any of those regions with a lower CMB temperature have matter at less than the CMB temperature. Admittedly, this is pretty much a cheat since you the CMB temperature should probably be considered a local value.

A stronger argument is that there probably are regions of space that are magnetically cooled below the local CMB temperature. All that is required for magnetic cooling is a mganetic field which will then preferentially trap particles with slower speeds parallel to the magnetic field. This is the same process that is at work in magnetic mirrors. Since magnetic fields are ubiquitous in space, its not too big of a leap of faith to assume that there are regions of space with higher than average magnetic fields that are far enough away from radiative sources that the magnetic cooling could bring the temperature below the CMB temperature. Regions behind intergalactic dust clouds could probably qualify.

Actually there is a freeware/shareware program called Graphic Converter that does the job for a reasonable price.

As for TeX, I also use it, but I use a nice tool called TexShop that is really nice, free and open source. It uses pdttex to compile and renders the file directly in pdf, so you get all the nice features of Quartz, like anti-aliasing.

... which is being done by a separate, none-FreeBSD project such as this one.

Its called STRIP - STarmode Radio IP, and there are Linux drivers. Check out the info at:

http://ns.uoregon.edu/~jremy/strip.html

There appears to be two modes to these modems: peer-peer or broadcast. Apparently Metricom calls their broadcast mode "starmode." These drivers allow you to basicly setup a wireless subnet. Very cool.

Can someone comment on the security of these modems? I might have to get myself a couple.

So, neutrinos can actually provide early warning*about a supernova. Light from SN1987a was in fact preceeded by neutrionos that arrived 18 hours ahead of time (ref-1) (ref-2).

Here is a really good page (among a bunch) that explains supernovae.

• Amateur Telescope Making by Albert Ingalls
• How to Make a Telescope by Jean Texerau

The stubby Celestron and Meade telescopes that are popular with amateur astronomers who prefer to purchase their instruments are of a type called a "schmidt-cassegrain". This has a nearly flat corrector plate in the front, that actually has a shallow fourth-order curve ground into it to correct spherical aberration, a deep prolate spheroidal primary mirror, and a convex secondary mirror mounted on the back of the center of the corrector plate.

It's the convex secondary that makes the telescope a cassegrain. The 200 inch on Palomar is a cassegrain. I don't have a schmidt-cassegrain to show you but here's how an ordinary cassegrain is laid out.

The use of the schmidt corrector plate allows one to make the telescope very short, with a small ratio of focal length of the primary to its diameter, without making images away from the center of the field blurry.

This is an advanced kind of design for an amateur to make oneself, although many amateurs have. Here's how one guy made a schmidt corrector plate.

The typical amateur starter scope is the "newtonian reflector". This has a concave parabolic mirror at the back end of the tube, and a few inches inside its focus is an optically flat mirror at 45 degrees. The optical path shown in the diagram is for the light from a single star, an image is formed from light sources spread across a small angle, and a small image is formed at the focal plane where it's examined by the eyepiece (a high-power magnifier) or photographed with film, a CCD or I guess even a webcam.

If you make a parabolic mirror with too short a ratio of focal length to diameter (the f-number, like the f ratio on a camera lens), then the images away from the center are blurred. This is called "coma". A parabola only focuses light perfectly if it's parallel to its axis and tilting the beam introduces coma. A ratio of 1 to 4 is about the shortest you can make it - f/4. My 6 inch is f/8, my 10 inch is f/3.5, and my 8 inch is f/6.

Having a longer focal length gives you greater magnification. Having a shorter one gives you a wider field of view, within the limits of the coma. Having a shorter focal ratio also makes it easier to fit in a car, an important consideration for making the scope enjoyable. Those Celestrons are nice because they'll easy fit in the trunk of a car or even in airline luggage (with a hard case) but it comes at the expense of a fancier design.

For the first homebuilt scope one usually grinds the primary and buys the flat diagonal mirror from a vendor. More advanced amateurs make their flats too but again optically flat surfaces are hard to make.

Making a primary that doesn't have too short a focal ratio is not too bad because the grinding process naturally makes a sphere. You grind a sphere of the right radius of curvature, fine grind through successively finer grits, then polish. You then use an optical test to get the mirror perfectly spherical, then deepen the center to move from a sphere to a parabola of revolution, testing carefully as you go.

The way I ground my mirrors was with pyrex mirror blanks on plate glass tools. Initially each is flat. They are both pretty thick, my 8 inch is about 1.25 inches thick, to stiffen them so they don't lose their figure. You have to have a figure that is perfect to about 1/8 of a wavelength of visible light in variation across the whole face of the glass, so any bending is disastrous. The 1/8 wave limit is the same for mirrors of all sizes so it's much harder to figure larger ones - best to start small. I would recommend an 8 inch for a first mirror. I have heard of people doing much larger first telescopes though.

What you do is sprinkle some granulated silicon carbide and water on the tool, place the mirror blank face down on it and push it back and forth until the silicon carbide ("carborundum") breaks down. (This is the same abrasive as you find on black wet-or-dry sandpaper, only in free-flowing powdered form). Then you add more abrasive and water and repeat. When too much mud builds up you wash it off and add more abrasive again.

To grind a concave curve into the mirror blank you place it on top, face down, grind with long strokes and have it hanging mostly off the side. Also you put pressure on it, either pushing hard or putting weights on it. This concentrates the grinding action in the middle and a shallow sphere develops.

Every few strokes you rotate the mirror a little, and once a minute or so you rotate the tool a little, with the idea that every part of the mirror gets ground over every part of the tool in every direction.

These days it has become popular to "hog out" a mirror with a metal ring tool, like a pipe cap as I'm about to try, then after rough grinding you make a fine-grinding tool out of small bathroom tiles mounted in dental stone or portland cement. This is in part because it's getting harder to get telescope making kits, unfortunately because it's so easy to buy a Celestron people don't make their own as much anymore. So people conserve the glass just for the mirrors and make the tile tools instead.

Be aware, before you say "well it's easier to buy a Celestron", that the price of a telescope goes up astronomically with increasing diameter - my 8 inch kit was $78 including shipping, I'll probably spend a few hundred to make a nice clock-driven mount, but the 10 meter telescope on Mauna Kea cost $90 million! If you know how to make your own, it is within your reach to grind your own 20 inch, which will have astounding views, but few of us could hope to afford to purchase a twenty inch commercial scope.

I know people who have ground 30 inch scopes and I know of some amateurs who are now figuring a 67 inch mirror!

Anyway it takes several hours of work to rough grind your mirror, more if you're doing a short f/number, less if you have a higher one, also less for smaller mirrors and more for larger ones. My 6" f/8 was about as deep as the thickness of an american dime, I don't know a little more than a millimeter.

Then you fine grind, grinding for a few hours with successively finer grades of abrasive. Usually you rough grind with 80 mesh silicon carbide - it is graded by sieving it through a mesh with 80 wires in it (same as the sandpaper sizes). Then you grind with #120, #220, #320, #400 and then several very fine grades of aluminum oxide whose sizes are given in microns.

The idea is that each finer grade erases the pits left by the previous grade. Between each grade you must scrupulously clean yourself, the mirror and tool and your work environment lest a coarse particle get into a finer stage and cause a scratch.

With each grade the mirror and tool surfaces will become more and more accurately spheres, within the limits of the sizes of the grits. This is because a sphere is the only shape that allows two surfaces to be placed anywhere against each other in any position or rotation (a flat surface is the limit of this as the radius goes to infinity). If there are any high spots, they will get more pressure and grind off quickly; any low spots will miss out on grinding and the surrounding surface will come down to match.

Then you polish. You make a "pitch lap", using either another dental stone base or the glass grinding tool, covered with refined, thickened pine pitch. You cut channels in the pitch with a knife or mold them in with a silicone mold. Then you cover the pitch lap with a suspension of cerium oxide in water, or else ferrous oxide (same as rust but finely powdered - "jeweler's rouge"). Then again you stroke the mirror on the pitch lap.

During fine grinding and polishing you use shorter strokes, and alternate which is on top, the mirror or the tool, to keep the depth constant. You also stroke a little side-to-side, in a W pattern. This evens everything out.

To test the mirror you use the Foucault test or the Ronchi Test. The foucault test appatatus I link to is much fancier than you need, although nicer to use - you can do it all with your naked eye and the tester, you don't need a camera.

In each test you use a light emanating from a pinhole or narror slit just to the side of the center of curvature of the mirror. The image of the pinhole or slit will form an equal distance to the other side, where you can place a knife edge (Foucault) or screen (Ronchi) across it and hold your eye there and look at the mirror.

It's kind of hard to explain but each of these has the effect of dramatically magnifying deviations from spherical surfaces in the mirror. A dramatic demonstration is to have someone hold their hand in the beam - you can see the distortion in the beam caused by the warm air rising from their hand.

You can easily make out a bump or hollow that's a fraction of a wavelength high on the glass.

Then you make your mirror perfectly spherical by preferentially polishing off the high spots. If you did the fine grinding and polishing well you won't have to work hard to do this.

Unfortunately what we want is a parabola, not a sphere. This must have a precisely controlled error in each test. This is a little more than I want to get into, but basically your preferentially polish out the center of the mirror so it's deeper in the middle than appropriate for a sphere by a little bit. Get it just right and you have a parabola, and your mirror will focus perfectly.

Then you package it securely and send it off to one of the people who does vacuum aluminization. They clean the mirror extremely well, place it in a high vacuum, and evaporate aluminum off of tungsten wires. The aluminum vapor sticks to your glass and you have a telescope mirror.

Mike

Another great student run station, KWVA in Eugene, Oregon. Quote from their website: "Tired of being torn from blissful slumber every morning by "Who Let the Dogs Out"?"

You can test whether your network is multicast enabled using the multicast tester applet. If you are, information about the content available can be found at the Internet 2 Multicast Calendar web site.

They play great, too! I've had some problems getting hardware accelleration working in Quake II but other than that all of these run great.

Check out the Linux Quake HOWTO, and the Linux DOOM FAQ.

Peace.

Claim your namespace.

mirrored on my schools webserver... try and slashdot that!

http://gladstone.uoregon.edu/~tehrenkr/opensource1 .gif

It seems to be just an edited version of this picture that was made for MP3s... Is there something before that?

http://gladstone.uoregon.edu/~tehrenkr/mp3.jpg

Fear my low SlashID! (bidding starts at $500)

mirrored on my schools webserver... try and slashdot that!

http://gladstone.uoregon.edu/~tehrenkr/opensource1 .gif

It seems to be just an edited version of this picture that was made for MP3s... Is there something before that?

http://gladstone.uoregon.edu/~tehrenkr/mp3.jpg

Fear my low SlashID! (bidding starts at $500)

As a U. of Oregon grad, I knew this couldn't be right. Change

limestone.uoregon.net
to
limestone.uoregon.edu

Here's a direct link to the 2.4 directory (it is FTP, but thing's pretty damn fast so you can probably easily fake it through your browser).

-orty

This is because for a disk to be bootable, it has to contain a chunk of code in its bootstrap that is byte-for-byte identical to some code held on ROM.

Fair use; no functional part of the game is being copied. The boot sector is simply a 14 KB magic cookie for "Dreamcast format CD" that happens to be executed. There are ways to route around the trademark issue also, such as displaying "NOT" right above any instance of "Licensed by Sega" as soon as your program gets control in Bootstrap 1. Case in point: Sega tried this with the Sega Genesis console (a "Trademark Security System"), resulting in Sega v. Accolade. From what I've read, this byte-for-byte copying is considered fair use; otherwise, what amounts to a perpetual patent could be achieved through copyright law.

Kinda reminds me of my first astronomy class. I hadn't even made it to my freshman year of high school and I had 4 credits of Astronomy from the local community college.

Many people have given good advice above. I'll mainly just second their comments. The order I'd proceed in is.

First item, a good beginners star atlas.

Second item, warm clothing.

Third item, many nights in the country just learning the stars and constelations.

After that go and get a good pair of binoculars or a good telescope.

Last, but not least. As your doughter is so young, you will need to be there as a source of infromation. You'll need to learn alot to help guide her in the early years.

Now for some Links. The first two have good beginners information. Some of the links below may be dead. I just quick cut and pasted them from the astronomy section of my Interesting Places page.

• Astronomy Mag. (www.astronomy.com/home.asp).
• Sky & Telescope Mag. (www.skypub.com).
• Minnesota Astronomical Society (MAS) (www.mnastro.org).
• The Telescope Shoppe (www.telescopeshop.com), 3402 Federal Dr., Eagan, MN, 651-688-7335. Yes this is a local Twin Cities telescope shop. They have a map on their site showing where they are. They are tucked in the lower level along the side of the strip mall they are in. The store is small and easy to miss. If your at the corner of Yankee Doodle RD and Federal Dr., park in the lot to the south east. They are a short stones throw from the intersection.
• Telescope making links
• • Many good links on making AltAz mounts (zebu.uoregon.edu/~mbartels/altaz/altaz.html).
  • ATM's resource List (www.freenet.tlh.fl.us/~blombard).
• Astronomy-Mall.com (www.astronomy-mall.com/Astronomy-Mall).
• Stellafane (www.stellafane.com).
• Terrestrial Planet Finder (tpf.jpl.nasa.gov).
• Many Images of the moon (www.seds.org/nineplanets/nineplanets/pxmoon.html) .
• Solar Views (www.solarviews.com).
• Planetary Image Atlas (www-pdsimage.JPL.NASA.GOV/PDS/public/Atlas).
• Hubble Space Telescope Archive (oposite.stsci.edu/pubinfo/pictures.html).
• Hummble Site (hubble.stsci.edu).
• StarStuff (www.starstuff.org).
• SpaceRef (www.spaceref.com), Your space refference.
• Astronomy Picture of the Day Archive (antwrp.gsfc.nasa.gov/apod/archivepix.html).
• SkyView (skyview.gsfc.nasa.gov) virtual observatory.
• 2MASS (www.ipac.caltech.edu/2mass/) and (pegasus.astro.umass.edu/GradProg/2mass.html) Two Micron All Sky Survey.
• Large Angle and Spectrometric Coronagraph Experiment (LASCO) (http://lasco-www.nrl.navy.mil/lasco.html).
• AAVSO Network to Search for Optical Counterparts of Gamma-Ray Bursts (www.aavso.org/grb.stm).
• High Altitude Observatory (www.hao.ucar.edu).
• Asteroid Comet Impact Hazards (impact.arc.nasa.gov).
• • Unusual Minor Planets (cfa-www.harvard.edu/iau/lists/Unusual.html).
  • Potentially Hazardous Asteroids (cfa-www.harvard.edu/iau/lists/PHACloseApp.html).& nbsp; Of particular interest to me are LB16 and AN10 which will pass at a distance closer than the moon's orbit. LB16 currently only has one opposition charted so it's predicted orbit will likely change as new data comes in. It's expected to swing by in 2004. In 2027 AN10 will visit earth. It's orbit is calculated with three oppositions meaning it't much more likely to really showup ontime and in place. With further data LB16 could either get closer or farther away. When AN10's orbit was first predicted (only one opposition at the time) it's error envelope included earth. With further data it was found to just pass within the moon's orbit and miss the earth.
  • Forthcoming Close Approaches To The Earth (cfa-www.harvard.edu/iau/lists/CloseApp.html).&nbs p; This is the document to look at when you want to know who will visit next and how far away. It has all close approaches to 0.2 AU away from earth or within 20% of the distance of between the sun and earth. On Sep 19th, 2000 we will have a visiter at 0.0477 AU and on Oct 31st anotehr one will pass at 0.07386 AU. LB16 and AN10 are expected to pass at around 0.25% of the distance between the sun and earth.
• Mars Global Surveyor (mars.jpl.nasa.gov/mgs/index.html).
• Mars Orbiter Laser Altimeter (MOLA) (ltpwww.gsfc.nasa.gov/tharsis/mola.html). There are full data on the shape of Mars including 1 degree and .5 degree elevation data sets.
• Planetary photojournal by JPL (photojournal.jpl.nasa.gov).
• NASA's Origins Program (origins.jpl.nasa.gov).