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Clayton Cramer's BLOG |
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Clayton's commentary on news and events of the day. Broadly speaking, I'm a conservative with libertarian sympathies (getting more conservative as my children get older).
 Never forget! I ran for Idaho state senate in 2008--didn't win I've written a number of history books, as well as scholarly and popular articles, (see my web page). Relocating to Boise? Use my realtor, neighbor, and friend, Cindy Smith csmith@1realtyone.com.
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Saturday, December 01, 2007
The Advantages of Having a Lathe I think I mentioned previously that the Chromacor is a very cool gadget that turns a so-so achromatic refractor into a well-corrected apochromat--but that because the Chromacor screws into the threaded barrel of diagonal assembly on the refractor, there's no way to use the Chromacor without the diagonal in place. This is a problem, because the diagonal adds several inches to the optical path, making it impossible for me to attach my camera to the telescope without removing the diagonal--and thus, the Chromacor. I decided to fix this, so I turned a piece of Delrin that replaces the diagonal. Since the 48mm threads are not a common tap (and I don't have a thread cutting attachment for the lathe), I bored out the interior end of the Delrin so that I can press fit a 48mm threaded filter in place. (I'll epoxy it in place for permanence.) Now I can screw the Chromacor onto the filter, and put it into the telescope without the diagonal. I now have the advantages of the Chromacor with the option of astrophotography! I didn't have a big enough piece of aluminum lying about; perhaps I'm look into making them out of aluminum for the ultimate niche market--Chromacor owners! Labels: machining, telescopes Continual Revision of the Big Bertha Redesign It turns out that Big Bertha's current diagonal mirror is larger than it should be (reducing image quality and light)--4.25". It turns out that if I reduce the mirror size to 3.1"--and increase tube diameter to 20.4" from 20"--I can get a nearly optimum combination of full illumination of the eyepiece and minimal obstruction. Of course, that means slightly enlarging the base plate the mirror cell (which I have not yet ordered), which increases the weight by a few ounces, and the weight of the two tube assemblies by an ounce or two. On the other hand, a 3.1" diagonal mirror is much lighter than the current diagonal. However: my choices on the square tubes that hold the tube ends apart are becoming frustrating. I had plugged in the wrong value for Young's modulus--using the stiffness of carbon fiber composite instead of aluminum. Now my choices are to go to a larger, considerably heavier set of aluminum square tubes, or spend the money on carbon fiber composite. The net effect is that using 1", .125" wall aluminum square tube gives me a total telescope weight of 67 pounds to get the total deflection down into the thousandths of an inch range--just too heavy. Going to .995", .060" wall carbon fiber composite gets me a 48 pound telescope with a comparable worst case deflection down below .004". The price of this stuff, however, is breathtaking--like $400 for the four tubes. Unless, of course, you know of a surplus carbon fiber composite dealer... Of course, I may be going too far on this. The deflection calculations are for the worst case--the telescope is pointing at the horizon. In practice, there is probably enough flex in a solid telescope tube that perhaps I can accept a few hundredths of an inch of deflection. I suppose that the worst that happens is I use somewhat smaller aluminum square tube (or two instead of four). For two square tubes, this gives me a total telescope weight of 57 pounds, and a maximum deflection of .014". If I need to, I suppose that I can add two more tubes. Labels: telescopes Astrophotography At 20 Degrees Beautifully clear last night--and incredibly cold because of it. (Okay, those of you in the Dakotas would probably be putting on swimsuits for 20 degree weather--but for me, a Southern California boy, this was cold.) The comet is showing more and more tail. It is still pretty subtle, but you can see that there is more than just a single fuzzy blob to it. I also used the 8" f/7 reflector this time--and unsurprisingly, it showed a lot more detail than the refractor. (More light.) Unfortunately, my attempts at taking pictures weren't so successful. I wasn't aimed as precisely on celestial north, and I wasn't prepared to spend the time getting properly aimed. Way too cold! Mars is bright, and there's a very noticeable disc (even at 45x), but it is still too low in the sky to get much detail yet. Why Fred Thompson Isn't Going Anywhere This is a painful November 30, 2007 Wall Street Journalarticle, because it is obvious that Kim Strassel has the same high opinion of Fred Thompson that I do--and why Thompson's campaign is turning out to be a complete bust in spite of a lot of very good proposals from Thompson: On Fox News this Sunday, Fred Thompson laid out the most creative tax proposal yet in the race for president. It should have been an important moment, the point at which GOP aspirants finally dug into a core issue and went a few rounds over marginal rates and corporate levies.The fundraising envelope from Thompson's campaign is in the bill drawer, scheduled for the middle of the month. But if Thompson's campaign doesn't start to catch fire before I get down to that bill, the temptation will be strong to hold onto that money for a Congressional or Senate campaign that shows a bit more ability to make something happen. Labels: 2008 presidential candidates This Might Cheer You Up These online polls don't mean much at all, because they aren't proper samples, and it is very easy for one side or the other to spread the word quickly to get their side to participate, but USA Today asked the following question: "Does the Second Amendment give individuals the right to bear arms?" As of right now, they have recorded 17,844 votes. Yes: 98%. No: 1%. Undecided: 0%. Labels: gun rights Mental Health & Politics "Republicans Report Much Better Mental Health Than Others" I am going to resist the urge to make a snarky remark about this Gallup survey that finds that Republicans are more likely than Democrats or independents to have excellent mental health. There is a substantive issue here--and the multivariate correlation analysis Gallup did suggests that Gallup found the results so amazing that they felt a need to figure out why. PRINCETON, NJ -- Republicans are significantly more likely than Democrats or independents to rate their mental health as excellent, according to data from the last four November Gallup Health and Healthcare polls. Fifty-eight percent of Republicans report having excellent mental health, compared to 43% of independents and 38% of Democrats. This relationship between party identification and reports of excellent mental health persists even within categories of income, age, gender, church attendance, and education.On page 3 of the report they show that when you correlate mental health against other variables, there are several factors that seem important: The numbers show that income is by far the most important correlation. Whining socialists may decide, "Of course. Rich people don't have any reason to have mental health problems." But more likely, people who are severely depressed are more likely to have trouble holding jobs. It is easy to see how mental healthy people will have higher incomes for that reason. Church attendance is the next most significant factor. Perhaps depression makes it hard to get out of bed on Sunday morning--but I would also find it plausible that a serious faith--one serious enough to get you to church with some regularity--might be a contributing factor to mental health. Education came in next, somewhat after church attendance. This doesn't surprise me, again, because people with serious mental health problems are less likely to be able to complete college. Being a Republican comes just after education. Do people with mental health problems identify with being Democrats? It seems rather difficult to see how mental illness would prevent you from being a Republican. The only other statistically significant factor was gender, but I can't figure out from the article whether men or women were more likely to be mentally healthy. Friday, November 30, 2007
Huckabee Must Be Doing Well in the Polls A Fred Thompson supporter encouraged me to link to this collection of video clips of Huckabee supporting higher taxes, SCHIP, more immigration, and a national ban on smoking inside any business. Smoking is a really vile habit, one that I hope will some day disappear. But with most private businesses, you don't have to go inside if you don't want to put up with smoking. If you want a non-smoking alternative, you can usually find one. I am not comfortable with states passing these kinds of bans (as Huckabee got passed in Arkansas), and it is an extraordinary reach to propose a national ban. Huckabee is trying to portray himself as a social conservative, with whom the smoking bans will probably go over well. But federalism is an important principle, one that Huckabee doesn't seem to understand. Labels: 2008 presidential candidates Time to Sue? A couple of days back, I mentioned the Alaska Airlines special discount for gay people. WorldNetDaily reports on one straight person who expressed his disapproval about being discriminated against--and the email response from Alaska Airlines was a vulgar expression that I won't repeat here. A reader asks: "Isn't this discrimination based on sexual orientation a basis for suit?" Well, to my knowledge, there is no federal law banning discrimination by private companies in the provision of services based on sexual orientation. But there are some state and local bans on it, such as the Seattle measure that the ACLU used to sue a print job owner because she refused to print same-sex wedding invitations. I don't know all the details on how a city ordinance applies to a national firm offering discriminatory pricing on a web site, but it would be amusing to see some straight people who live in Seattle file suit against Alaska Airlines demanding that they stop. You understand, I have very little sympathy for laws that tell private firms with whom they have to transact business--but full application of stupid laws sometimes gets the message across to the stupid people that advocate them. Such public accommodations laws are certainly constitutional, and part of a long English common law tradition. I just consider these a very questionably necessary governmental action that imposes unnecessarily on private property rights. I really don't think that the government should be telling consenting adults what they should be doing on private property, and it shouldn't matter if that's employment or sodomy. I make one exception on this: blacks were the victims of widespread state imposed private business discrimination for many decades. If you find this surprising--that the government actually ordered private businesses to discriminate, read Plessy v. Ferguson (1896) for details. Similar discrimination was imposed on interstate bus companies as well into the 20th century. In 1964, you could make a good case that the Civil Rights Act was necessary to break a pattern that had been imposed by state laws, and aggravated what was a widespread, popular, and natural discriminatory practice. (Yes, "natural," in the same sense that Granola, cholera, and death in childbirth are "natural." Natural doesn't make it good.) I'm not sure that the argument for this is all that strong today--and I've never found the argument for all the other groups that are now protected by these public accommodation laws all that persuasive. Labels: ACLU, equal protection, homosexuality More About Deformation of Plates That question I asked yesterday about calculating deformation caused by load generated a lot of useful leads! A reader pointed me to this calculation website that appears to be about as closely matched to my needs as I can imagine. It calculates deformation for a circle that is supported by a ring at various radii of the circle. All you have to do is enter the force (which should include that generated by the plate itself), the radius of the circle, the radius of the support, the Young's modulus in gigapascals, and thickness of the plate, and it calculates the displacement in millimeters. Now, three screws supporting this isn't quite the same as a uniform ring, but I suspect that it will be close enough for my purposes. I'm going to go a little thicker than absolutely required, just for that reason, but even for .09" thick aluminum, the displacement is in the hundredths of a millimeter area--or about .002". That's fine. Labels: machining, telescopes Thursday, November 29, 2007
Humor: Mad Moose Incident Do I believe the attached story and picture sent by a friend? Not for a second. But it brought a smile to me, and I figured you might enjoy it too. UPDATE: Snopes tracked it down and says that it is true! Labels: humor Political Correctness and Hip-Hop Mug Santa Someone please tell me that isn't serious. Because if it is, this is very serious. From one of the South Africa news services: Sydney - Santas in Australia's largest city have been told not to use Father Christmas's traditional "ho ho ho" greeting because it may be offensive to women, it was reported on Thursday. Labels: decline and fall of Western civilization, political correctness Question For Black Powder Shooters I am seeing ads from the 1730s in South Carolina that are offering pistol-powder. Am I correct that black powder intended for pistols was finer grained so that it would burn more rapidly, to accelerate the bullet more quickly out of the short barrel? Labels: gun history Arkansas Attorney-General Signs On Nice to see another state attorney-general agreeing to take our side on the DC suit: Thanks to Arms and the Law for the link. Labels: gun rights Today's Mechanical Engineering Question I found this page that tells me that the deformation of a member is equal to the force times the length divided by the Young's modulus, and again divided by the cross section of the member. The application is I am trying to figure out how much deformation a sheet of metal (probably aluminum) of a particular thickness will suffer when a particular weight is placed on it, said weight being evenly distributed across the entire surface. When the surface if parallel to gravity would seem like the most severe strain, so I can use this as my worst case. I suspect that the equation looks something like: F = pressure in newtons (kg * 9.8) L = width of the sheet in meters X = thickness of the sheet in meters Y = Young's modulus for the material in newtons/square meter D = FL/Y/X If the force were exerted over only a small part of the sheet, the equation would be more complicated (and I suspect the deformation would be more severe). Any hints would be appreciated. I'm trying to get the minimum thickness of aluminum sheet for the mirror cell to reduce cost, weight, and the difficulty of cutting the parts. UPDATE: A reader points me to this explanation of determining deflection intended for those building model railways. It's still a linear situation where I am looking at a circular situation, but I suspect that treating the diameter of the circle the same as a rectangular beam is probably pretty close. Labels: machining, telescopes David E. Young's New Book Is Almost Out David T. Hardy discusses it here. I ran into Mr. Young at the Gun Rights Policy Conference--and he warned me that the 1757 Pennsylvania militia act that I had on my web site was never signed into law. I found this implausible, since it appeared in Statutes at Large of Pennsylvania From 1682 to 1801, which should mean that everything contained therein was at one time a law of Pennsylvania. Young was right. There are a number of measures contained in that set that were never passed into law. Labels: gun history Wednesday, November 28, 2007
Understanding Bush Derangement Syndrome It has been among the great curiosities of the last several years is the extent to which otherwise relatively sane people (and the left, also) have gone completely and utterly bananas in their ascribing to George Bush all kinds of demonic intentions and plans. I could understand and disagree with the non-interventionist critique of invading Afghanistan, and even the pragmatic objections to the Iraq War (which would have been much stronger if anyone had realized how badly Bush would screw it up). But when you here otherwise non-tinfoil hat sorts talking about Bush is going to cancel the 2008 elections, for example, or the entire cult that has developed around theories that Bush either actively caused or passively allowed the 9/11 attacks to take place--well, you have to start wondering what's in the water that these people are drinking. A person I know who spends a lot of time teaching college students suggested an interesting explanation for this recently which just happens to collide with a book that I am currently reading: Mary Beth Norton's In the Devil's Snare: The Salem Witchcraft Crisis of 1692. I'm not done reading it, but she has a new twist on what provoked the Salem Witch Trials. Many of those who were participants, either as "victims" of the witches, or the witches themselves, were refugees from the Maine frontier, driven back into Massachusetts by a series of ferocious Indian wars. Norton argues that unlike other witchcraft trials of the period, where judges were a lot less willing to accept "spectral evidence," and a lot more willing to give accused witches the benefit of the doubt, many of the participants were dealing with traumatic consequences of the loss of community, and of enormous fear of attack. That the Indians were regarded as Satan worshippers throughout this period made it very easy to see the loss of the Maine frontier as having Satanic overtones. Anyway, it strikes me that perhaps what we are seeing with the more bizarre theories that are floating about is a modern version of this same problem. George Bush, as much as the left hates him, isn't going to drag any feminists off in the dead of night to be beheaded. He isn't going to be imposing sharia law. Even those with the most liberal politics have to admit, if rational, that if George Bush got his way without restraint, America would still be a far nicer place to be a feminist, homosexual, or atheist, than any Muslim nation. Social conservatives just aren't that scary compared to even "moderate" Islam. Any rational liberal or leftist would look at the enemies that we are fighting, and be scared to death of them. For those Maine frontier refugees, the enemy "out there" was far more ferocious, far more dangerous, than anyone within their own society. Especially among those who started the Salem hysteria (a bunch of teenaged and younger girls), the enemy that they really feared, and with good reason, was not an enemy that they could do anything about. They were powerless, and they were not warriors. They could do something about people closer at hand, and who were not going to kill and mutilate them--people like Rev. George Burroughs. I think we are seeing something similar today: liberals have always regarded our military as a necessary evil, and the left hasn't even admitted "necessary." The only tools to fight the Islamofascist enemy are those that the left end of America has never identified with in any way. Like those terrified girls, it is easier for the left to redirect its fear onto a target that is closer, and less dangerous--and most importantly, that they can do something about. George Bush doesn't require an unrelenting battle to unseat--just an election. Labels: conspiracy theory, terrorism Time For Idaho Attorney-General Wasden To Take Action I mentioned a couple of days ago that Michigan's Attorney-General wrote a opinion piece for the Wall Street Journal about the D.C. gun control suit before the U.S. Supreme Court. It turns out that a number of state attorneys-general are preparing amicus curiae briefs in support of the individual rights understanding of the Second Amendment. Red's Trading Post wants Idaho's Attorney-General Wasden to do likewise. It seems appropriate to me, especially when you look at the nonsense that Red's is having to go through just to stay in business. Idaho residents, this is your chance to do your part: contact Wasden, and tell him to join the parade. Labels: gun rights Making Big Circles I need to make some big circles--20" and 17.5" in diameter, out of 1/4" aluminum plate. But that's too big for a lathe that I have. It turns out that there are several ways to do this, both using a router, and using a table saw. Here's one of the better examples of how do this with a table saw (probably the best choice for me in the size that I am going to need). I've been experimenting with what was laying around the garage, and I have some confidence that I can do this, perhaps even pretty well, and most importantly, while leaving all my fingers firmly attached to my hands. Three tricks to this: 1. The board that holds the workpiece needs to be big enough that you can clamp it very securely to the table. You won't be able to hold the board tightly enough when cutting anything as tough as Delrin or aluminum. 2. The thickness of the board that holds the workpiece, plus the thickness of the workpiece, needs to be less than the height of the blade on your table saw. In this case, I have a somewhat smaller than normal carbide blade in the table saw, so I may need to get the standard diameter blade to get the height up a bit. 3. The example above uses 1/4" holes in the board into which the bolt that acts as an axis of rotation. I've decided that for my purposes, I'm going to use a tapped 3/8"-16 hole in the board (which will be aluminum or steel, depending on what I can find most available). The axis hole in the workpiece is a through hole so that it can turn freely, but using a threaded bolt to hold the workpiece in position to the board prevents the torque of the blade from ripping the workpiece free and sending it flying. You have to make sure that you don't use too long a bolt, of course, because the board has to clamp to the table. I would not recommend using this approach to cut very small circles, because then your fingers are dangerously close to the blade. Since I'm planning to cut 17.5" and 20" circles (for the mirror cell), my fingers never have to get closer to the blade than a bit less than half the radius. I'm looking at making a mirror cell rather than buying it because: 1. There aren't many vendors of 17.5" mirror cells intended to put into a tube. Many of the commercial sources are Dobsonian-targeted (which means a big square frame). Discovery Telescopes apparently makes one, but review comments like this one aren't confidence inspiring, especially since Discovery Telescopes webpage seems to have disappeared. 2. AstroSystems makes a 17.5" mirror cell which is probably quite good, since Company 7 sells it, but the weight of 16.6 pounds seems excessive. I believe that I can fabricate my own for a fraction of the cost, and about half the weight. (And weight reduction is the whole reason that I am rebuilding Big Bertha.) A reflector mirror cell consists of the following parts: 1. A base plate that attaches to the tube. Typically, there are three screws (sometimes more) that pass through the tube into a flange on the base plate. Both for ventilation, and to reduce the weight, I'll will put in some lightening holes. 2. A mirror plate with a ring in which the mirror sits. At the top of the ring are usually three clips that prevent the mirror from falling forward out of the ring. The mirror plate usually has a series of 9 or 18 points that support the mirror arranged in a pattern that provide air flow around the base of the mirror, to speed up cooling. My experience has been, however, that a heavy ventilated solid mirror plate works well, too, and saves a bit of weight. 3. Three big screws that attach the mirror plate to the base plate, with springs in between the mirror plate and the base plate. Some designs have the screws coming off the mirror plate actually part of the stamping, but I have discovered that tapped holes let you use standard bolts. There are through holes in the base plate, and wing nuts on the screws, which provide a secure method of adjusting the collimation. I have used 1/4"-20 bolts in the past for this for big Big Bertha's current primitive mirror cell, but because of the weight involved, it would be tempting to switch to 3/8"-16 bolts. I think the springs that I am currently using for this will still fit over 3/8" diameter bolts. UPDATE: It turns out that I can get the circles cut out of 1/4" aluminum for $220--which suddenly makes the cost of buying a mirror cell not seem so extravagant. Hmmm. Maybe using 1/8" steel starts to make more sense. My guess is that even 1/8" aluminum would still be more sufficiently stiff, easier for me to cut into circles, and it would take some more weight off the complete telescope--especially at the tail end, where there's the most deflection caused by weight. UPDATE 2: A reader suggests that trying to use the technique above should be restricted to small cuts--that it would be safest to trim the square to a rough circle first. I may in fact go to hexagons instead. Labels: machining, telescopes A Special Discount, Just For Them! If I couldn't click over to the website and see it for myself, I wouldn't have believed it! Alaska Airlines is offering a 10% discount on some fares for their gay customers: Gay Travel Look, when corporations tell homosexuals, "Hey, you're welcome to do business with us! We love having you fly with us," I find it slightly annoying, but when they go out of their way to favor homosexuals with discounts that are apparently not available to us straight folks--where's the justice in that? Do gay people use 10% less fuel to fly? Are they 10% less difficult to serve beverages and salted peanuts to? This is absurd. Imagine the uproar if Alaska Airlines were offering a 10% discount to white people, or a 10% discount to men. I suppose that you could just pretend to be gay to take advantage of the discount. Labels: homosexuality Tuesday, November 27, 2007
Product Review I submitted this a couple of days ago to Astromart.com. It's a review of the Orion Dynamo power pack for telescope mounts. Labels: telescopes Bad Head Cold That's why there's not much happening here at the moment. I spend almost all my time drinking NyQuil, and trying to sleep. Sunday, November 25, 2007
Michigan's Attorney-General on the D.C. Suit In the November 23, 2007 Wall Street Journal: To analyze what "the right of the people" means, look elsewhere within the Bill of Rights for guidance. The First Amendment speaks of "the right of the people peaceably to assemble . . ." No one seriously argues that the right to assemble or associate with your fellow citizens is predicated on the number of citizens or the assent of a government. It is an individual right. Except for using Jack Rakove's own words against his position (which is surprisingly easy to do, since Rakove's position about the Second Amendment is contrary to much of his published work about the rest of the Bill of Rights), there's nothing here that is really new. But it is still welcome. Labels: gun rights Fred Thompson: If This Is Fake, At Least He's Doing It Well And at least he knows to which side to pander. From November 24, 2007 CNN:
Labels: 2008 presidential candidates More Fun With Fiberglass I made another try, wrapping the fiberglass glass radially around the cardboard tube, instead of applying it to the exterior face. I can't say that it made any better of a surface, but it means that the interior of the tube is now too small for the 20" OD mirror cell that I was planning to use. The good news is that the fiberglass does definitely stiffen these tubes substantially with only a small increase in weight. The bare tube weighed 2.5 pounds; after applying the fiberglass cloth radially, it is now 3.5 pounds--and is obviously much stiffer. I'm not sure that it is quite stiff enough for a telescope tube, but perhaps one more layer (on the outside) would do the job, and only get the weight up to 4.5 pounds per section. I do think it might be worthwhile to try and buy the thicker Sonotube from the operation in Bozeman, Montana, even with the shipping charges, just to get the extra stiffness. Perhaps I won't need to use fiberglass cloth with the thicker Sonotube--maybe just applying the resin inside and outside will be enough. Since the thicker Sonotube weights 3.3 pounds/foot for the 20" ID form, the tube will be 2.2 pounds per section. With the resin applied, even in two layers on the outside, this should still be less than 4 pounds section. Labels: telescopes |
