Thursday, June 29, 2006

My Wife Can Stop Insulting Big Bertha

With the adjustments mentioned here, the old girl shows more detail on Jupiter at 222x than I can draw--gobs and gobs of belts, festoons, and detail just below the edge of what I can describe. However: the collimation doesn't stay for long. I think the mirror supports need to be a bit tighter against the mirror, and the diagonal holder needs to be a bit more tightly screwed into the spider.

For its inches of aperture, I would agree that the image quality degrades faster than I would expect. But at the same magnification, it shows more detail than smaller scopes. This is expected, since resolution increases linearly with the diameter of the objective. Even a so-so 17.5" mirror should handily outperform even a very good 5" refractor under stable skies (which I have).
What A Remarkable Material Acetal Is

I've sung the praises of this stuff--a polymerized formaldehyde (also sold under the brand name Delrin)--before, but since I am considering replacing some crudely made wooden parts on Big Bertha with machined plastic, I thought I would see how much lighter it is than aluminum.

Aluminum is 2.768 g/cc; Delrin is 1.41 g/cc.

Aluminum's ultimate tensile strength is 90 MPa (megapascals, if the abbreviation is new to you); Delrin is 75.8 MPa.

That means that aluminum is twice as dense and only 19% stronger. (There are several other measures of strength, but as a rough approximation, ultimate tensile strength is a good start.) If you can make something of a sheet of aluminum that is an inch thick, you can make it of Delrin of the same size, and end up with something about 20% stronger, and half the weight.

Now, compared to wood, this is a bit more complex, but it appears that woods like pine have about 35% of the tensile strength of aluminum, and about 21% of the density, so pine still has its virtues as a structural material. But pine's strength to density ratio is pretty close to Delrin--and Delrin is less likely to have the defects common to natural materials.

UPDATE: A reader points out something that I should have checked--the modulus of elasticity of aluminum is about 20x that of Delrin, so that for the same size, aluminum is far stiffer, and less prone to bending under load. There are still places where Delrin works well, but for anything where you need a surface to not bend, aluminum is still the better choice.

Tuesday, June 27, 2006

How To Make The Clouds Arrive

I mentioned a couple of days ago about looking at M51 (the Whirlpool Galaxy) though Big Bertha, and how it wasn't looking quite as good as I had hoped--perhaps because the collimation was a bit off.

Indeed, one of the frustrations of Big Bertha is that it doesn't have a mirror cell in the conventional sense. Instead, at the back of the tube is a big flat piece of wood mounted on a hinge. The collimation screws go through that piece of wood. The hinge allows you to drop the back in order to remove the mirror--absolutely necessary if you are going to move this behemoth.

Well, one problem of the hinge is that at the far side of this square of wood is a gate hasp, to keep it from flopping down in use. Necessarily, that gate hasp means that there as much as one-sixteenth of an inch of play--and that means that, depending on the angle of the telescope relative to the ground, you could have quite a bit of variation in where the mirror is sitting relative to the rest of the optical train. Since collimation involves moving different sides of the mirror thousandths of an inch, this means that collimation has never been spectacular. You can collimate in one position--and as soon as you move the tube across the sky, that collimation is now worthless.

So I got fed up this slop, and sank two 1/4"-20 threaded studs into the back of the tube assembly, on the side of the big flopping square where the gate hasp is. Now there are two nuts that, once tightened down, reduce the slop to something I can't immediately see. Collimation seemed easier and more precise--and since I now have probably increased the optical precision of Big Bertha by a couple orders of magnitude--the clouds came in!
Male Homosexuality & In Utero Influences

This BBC report says that a recent study suggests that the odds of a man being homosexual increase as the number of older brothers increase:
A man's sexual orientation may be determined by conditions in the womb, according to a study.

Previous research had revealed the more older brothers a boy has, the more likely he is to be gay, but the reason for this phenomenon was unknown.

But a Canadian study has shown that the effect is most likely down to biological rather than social factors.

The research is published in the journal of the Proceedings of the National Academy of Sciences.

Professor Anthony Bogaert from Brock University in Ontario, Canada, studied 944 heterosexual and homosexual men with either "biological" brothers, in this case those who share the same mother, or "non-biological" brothers, that is, adopted, step or half siblings.

He found the link between the number of older brothers and homosexuality only existed when the siblings shared the same mother.

The amount of time the individual spent being raised with older brothers did not affect their sexual orientation.
This is an interesting claim, but I do find myself asking some questions.

Bogaert controlled for older brothers with the same biological mother--but I can't tell from this study if he controlled for the presence of the biological father or not.

The absence of biological fathers increases the risk for both boys and girls of molestation, for a complex set of reasons, partly because biological fathers seldom molest their own kids, partly because the same taboos that discourage this are not operating with stepfathers and live-in boyfriend of the week, and partly because children looking for father figures are more likely to look for approval from adult men--and are thus subject to inappropriate advances. We had a babysitter in Irvine whose father was long gone--and this approval seeking from adult men led into a van with a 45 year old who did maintenance work around the complex. This being California, the creep received two years weekend jail time for sexual intercourse with a 13 year old.

Since family size has fallen so dramatically in the last forty years, there are relatively few traditional families anymore that have more than two boys in them. I would suspect that families that have more than two boys in them are disproportionately "blended" families. It is possible that Bogaerts' study is seeing the consequences of increased molestation because of the presence of non-biological fathers in the household.

This previous paper by Bogaert indicates that the male birth order effect is correlated with older brothers only; not the number of siblings, nor with older sisters.

Bogaert's other work doesn't seem very PC. This paper's abstract of which Bogaert is an author shows that there is a correlation between men who go after little boys and men who are interested in other men:
We investigated whether late fraternal birth positions also occur in homosexuals attracted to children or pubescents. Probands were 710 sex offenders from Gebhard et al.''s (1965) study of sexual offending. Homosexual offenders against adults and pubescents had later fraternal birth positions than heterosexual offenders against adults and pubescents, respectively; there was no difference between the homosexual and heterosexual offenders against children. Results provide some evidence that homosexuality in men attracted to immature males is etiologically related to homosexuality in men attracted to mature males.
This other paper's abstract by Bogaert also suggests that homosexuality isn't so different, regardless of whether the intended partner is adult or immature:
The subject's relative attraction to male and female children was assessed by phallometric testing in one analysis, and by his offense history in another. Both methods showed that fraternal birth order correlates with homosexuality in pedophiles, just as it does in men attracted to physically mature partners. Results suggest that fraternal birth order (or the underlying variable it represents) may prove the first identified universal factor in homosexual development. Results also argue against a previous explanation of the high prevalence of homosexuality in pedophiles (25% in this study), namely, that the factors that determine sexual preference in pedophiles are different from those that determine sexual preference in men attracted to adults. An alternative explanation in terms of canalization of development is suggested.
Interesting: 25% of pedophiles are homosexual in the study. Hmmm. Homosexual men are about 3-4% of the population. It does appear that there is a disproportionate number of homosexuals among pedophiles.

There's actually a lot of interesting research this guy Bogaert has published that suggests the possibility that male homosexuality is fundamentally different in its causes than female homosexuality. Male homosexuality may a form of maternal immune system defect that causes the damage and confusion, leading to early puberty and enlarged genitals.

Saturday, June 24, 2006

House Project: The Results of Designing With the Environment (& Money), Instead of Against It

One of the decisions we made early on was that every window in the house would be openable, so that we could take advantage what breezes were available--even if meant that what might have been a spectacular picture window ended up as a sliding glass door instead.

Yesterday and today have borne out the wisdom of this decision. It is the mid-90s down in Boise. Here, 1300 feet higher up, it has been in the mid-80s. In our old house, which had only a few opening windows, and lots of picture windows, the only realistic choice would have been to turn on the air conditioning--you just could not get enough cross-ventiliation to make this comfortable.

In this house, the cross-ventiliation has worked as I expected. I have nearly every window in the house open. Since there are windows on the south, east, and north sides of the house, I am catching breezes from all directions. Outside, in direct sunlight, it is warm enough to be a bit uncomfortable. For most of the day, it has been entire pleasant or tolerable enough that changing into shorts and a T-shirt was sufficient to be comfortable. It is only been since about 4:30 PM that I have been tempted to turn on the air conditioning--and now that is a bit after 6:00 PM, the late afternoon breezes are again bringing the interior temperature to a point where air conditioning would be only a minor improvement. Best of all--I don't have to pay for the wind!

Last house project entry.
Dark Skies & Things That Go Bump in the Night

It is really dark up here. I dragged Big Bertha out of the garage Wednesday night, trying to find M51 (the Whirlpool Galaxy). No luck. I'm sure it's dark enough--I just need to spend a bit more time with the locator charts that show where it is relative to nearby stars.

I confess that I have never put much time into looking for deep sky objects (i.e., galaxies, nebulae, and other faint fuzzy bodies) because I have never lived somewhere dark enough for this to be useful. Now I do--but that means that I have to learn where these objects are.

As an example, M57 (the Ring Nebula) is a planetary nebula in the constellation Lyra. It is bright enough that you can find it from almost any suburban location--and you don't even need a huge telescope to see it. I saw it (with averted vision) with my Televue Ranger, which only had a 70mm front lens. But to find it, you need to know where to look. It is on a line between Beta Lyrae and Gamma Lyrae, about 2/3 of thw way between them. If you start out with too low of a power on most telescopes, you won't see it, because it is pretty small, and you may not be able to distinguish it from a star. If you start with a high enough magnification to see that it is a smoke ring, not a point source, you have to pretty much on it, or you will be wandering through the celestial neighborhood, and never hit it.

The same is true for most other deep sky objects--some are barely visible with the naked eye (and most are not), so you need the light gathering ability of a telescope to have any hope of finding them.

Anyway, because I knew where to look for M57, I had no problem finding it with Big Bertha. Even with a low power eyepiece (about 80x), M57 was obviously not a star. On a smaller scope, you can't really go up much above 100x, because the image becomes too faint to see. (Higher magnification with the same amount of light yields contrast problems.) With Big Bertha, even at 222x, M57 was still easily visible.

Along with the darkness of the sky, there is the darkness that brings out critters. Thursday night our dog went absolutely bananas in the wee hours, barking ferociously at the sliding glass door in the family room. My wife couldn't see what she was barking at--but the front motion detector lights came on as well. (I slept through it.) What was it?

Today I was walking back from the mail box, and ahead of me on the road was what at first looked like a small dog--but turned out to be a coyote. Conforming to their reputation as being shy and retiring creatures, it bounded up the hill along the boundary line between our parcel and lot 3 to the south.

Tuesday, June 20, 2006

House Project: Something For Next Time I Have To Engage in Algal Genocide

I mentioned previously my fun with chlorine bleach to kill algae and sterilize. A reader points to this recent item from Microbe magazine. (No, it's not the magazine that the young, hip, urban bacterium reads for lifestyle hints, but a publication of the American Society for Microbiology.)

Bleach is sold as a stable alkaline solution with a pH value of about 11 or 12. At this alkaline pH value, virtually all of the bleach is in the form of the chlorite ion (OCl-). At an acidic pH value of about 6.0 to 6.8, 90% of the bleach is in the form of hypochlorous acid (HOCl). Hypochlorous acid is 80 to 200 times more antimicrobial than the chlorite ion. Thus a simple formula to prepare an effective antimicrobial dilution of bleach is to add 2.0 oz of concentrated bleach to one gallon of tap water, and then add 2.0 oz of 5% distilled white cooking vinegar, also inexpensive and commonly available, to lower the pH of bleach to about 6.0. This will yield about 800 ppm free available chlorine from hypochlorous acid. Use this acidified bleach in well-ventilated areas as there will be a mild odor of chlorine.
Yes indeedy, there will be the smell of chlorine gas, so be very, very careful with it. But it does suggest that next time, instead of using 15 gallons of bleach, I can use a gallon of bleach and a gallon of vinegar to get the same result, with less unpleasantness in the water while it works its way through the system.

Saturday, June 17, 2006

House Project: Back In The Tank!

Okay, I mentioned a few days ago that we had engaged in algae genocide using lots of bleach--and it worked. But then, during a very heavy rainstorm a couple of days later, the water suddenly turned brown! Huh? So I went up to the water tank, and I found myself wondering if the lid wasn't properly tightened on it, and perhaps some water had sneaked in under the lid.

This is worrisome, not only because the color is unappetizing, but also because cattle have grazed on this hillside in the last couple of years, and who knows what charming bacteria might be sneaking in with the color. So we decided it was time to make another expedition into the water tank.

In the meantime, I mentioned my concerns to the builder, who just casually mentioned, "You know, the gasket for the water tank lid is hanging in the garage." Sure enough, this is a big chunk of rubber tubing that is supposed to make a really tight seal. Why didn't the builder put in place six months ago? I wonder how much of our dirty water problem was related to this? One more reminder that our builder got a big chunk of money for doing a haphazard job--and dropping the ball on important stuff.

So, yesterday about noon, we started draining the water tank. I couldn't quite remember how we did it last time, but this time, I started draining the frost-free faucet (which is a direct gravity feed from the tank). When it stopped draining, I expected to just siphon the remaining water out of the tank with a garden hose, like we did last time.

We could not get the siphon going. After a lot of suffering, I concluded that the problem was that last time, we started the siphon with a full tank of water. So we refilled the water tank (which only took about 45 minutes to move hundreds of gallons from the well), and tried again! Success! The siphon, plus running all the faucets in the house, emptied it down to a few inches of muddy water at the bottom of the tank.

Down again I went into the tank, using a couple of buckets to get it empty enough for the shopvac to not be a modern analogy to emptying the ocean with a eyedropper. The shopvac did a decent job of pulling up mud and silt--and there was a lot of it. I'm glad to report that there was no algae, however.

Rather than use bleach in a spray bottle (several thoughtful readers thought that might be a bit too hazardous in a confined space), I used Clorox disinfectant wipes--and discovered that they weren't so useful. The last thing I needed was more liquid. Regular paper towels did a nice job of cleaning the tank to a smooth shiny white surface. Unlike algae, mud wipes up well.

After exiting the tank, we poured in two bottles of bleach (perhaps three gallons total), wiped down the lid and the gasket with bleach, and then refilled the tank.

There was still a bit of brown to the water for the first few hours, but it all seems to have worked its way out. Having the gasket in place when putting the lid back on the tank made quite a difference. I now have confidence that nothing is going to get back in around that lid.

I had mentioned to my builder that I was planning to write a book about this experience. "Just don't mention my name." I'm glad that he is aware that wouldn't want his name mentioned. I just wish it provoked him to do his job a bit better.

Last house project entry.

Thursday, June 15, 2006

House Project: Aren't Towel Racks Normally Screwed Into Studs?

My daughter is visiting, grabbed the towel, and pulled the towel rack right out of the wall. She's not exactly a female version of Governor Schwarzenegger. It appears that the towel rack is mounted to the drywall using a rather large type of plastic screw. I'm very disappointed, and I've emailed that disappointment to the builder.

Last house project entry.

Wednesday, June 14, 2006

House Project: Jetted Tub Problem Was Just a Matter of Instructions

I mentioned a few days ago that some of the jets on the jetted tub weren't working. After a bit of discussion, the problem turned out to be that while the little dials around the top of the tub control the total flow of water through these jets, pushing in on the jets turns off the flow completely, and pulling out on them turns on the flow. This is a binary decision: flow, or no flow. This also explains why one of the jets that had been working, stopped working--presumably because I ran into it, and pushed it in.

Anyway, I happy to report that everything is working. My wife, who at first thought this was something of an extravagance, reports that the jets do wonders for her aching hip muscles. Men: be glad that you don't have babies.

Last house project entry.

Tuesday, June 13, 2006

House Project: The Washing Machine's Problem

I had mentioned previously that the washing machine was trying to move north to Canada. GE's warranty guy came out this morning, and discovered that when the builder installed the washing machine, he neglected to remove the shipping rods and a big chunk of Styrofoam that protect the machine from damage in shipping. The shipping rods prevent the drum from moving up and down on its suspension, thus transferring vibration from the drum to the frame, and then to the floor--hence the walking. There was no damage caused to the washing machine by this failure to properly install it, but it is rather frustrating to see such a minor detail missed.

Last house project entry.

Monday, June 12, 2006

House Project: Fun With Bleach

I have mentioned previously that the water tank wasn't properly cleaned before putting it into service, and after removing gobs of mud and a bit of algae, the water looked much better. At the time, I ran out of paper towels while cleaning the interior of the tank, so the last 1/4 of the tank still had a slight greenish tinge to the walls--but I thought, "Good enough."

Well, no. The water was beginning to get a little green again--enough so that my wife wasn't keen on using the bathtub. Looking in the water tank was grim. So after leaving a whining message for my builder, I searched the web and found out that the correct solution to algae is bleach--about 1/6 of an cup for every ten gallons of water (at the Clorox standard of 5.25% sodium hypochlorite).

Well, this worked. We found an industrial strength version of Clorox at Lowe's (but not at Home Depot), and we poured in about 15 gallons of the stuff. Then, on Sunday afternoon, we started emptying the tank through the frost-free spigot, to avoid unnecessarily running dead algae through the filters. (The frost-free spigot feeds directly from the water tank, gravity fed, and no filtration.)

By the time we came back a few hours later, the combination of genocide against algae and draining the water tank had substantially cleared up the water coming out of the taps. Of course, it now smelled strongly of bleach, so we just kept draining. By Monday evening, the water from the taps smells fine. It still isn't quite as clear as I would like--and a little green frog jumped into the water tank before I started pouring the Clorox in-- but I think the solution is to repeat the cleaning operation--and not run out of paper towels this time.

I believe the solution is Saturday morning:

1. Drain the water tank.

2. A few hours later, climb inside and vacuum it out.

3. Spray the interior with Clorox.

4. Wipe down the interior with paper towels.

5. Refill the tank.

Last house project entry.

Saturday, June 10, 2006

House Project: Kudos To Our Builder; Kudos To The Maker

I've been complaining a bit about slow follow up to our complaints and occasional lack of attention to detail. Let me say something nice here about our builder. The frame under the exterior doors was sealed with some sort of foam. It wasn't very attractive, but I never got around to whining to our builder about it. But sometime in the last couple of weeks, he came up and put in a nice piece of wood that made it all look quite a bit more buttoned down.

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No complaints about the Builder of the world. Here's some pictures I took from around our house after breakfast: Morning in Horseshoe Bend.

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Last house project entry.

Friday, June 9, 2006

House Project: Fun With Appliances

There aren't many house project entries left, since we have moved in, and there is only one significant task left for the builder--epoxy painting the concrete to solve the problem of inconsistent coloration. But there are a few surprises, some of them amusing, some just irritating, that have come up since we moved in Monday night.

Washing Machine & Dryer

We have run a few very small loads through the washing machine, and it has worked just fine. Then, we put in something close to a real load--and during the final spin cycle, it started walking its way out from under the counter, headed north. ("You don't normally see that kind of behavior from a major appliance.") Then, after my wife turned it off (before it decided that it wanted to be Canadian), she noticed that the dryer wasn't drying clothes.

At this point, my wife, who has developed a certain level of anger at our builder for a certain lack of follow-through on details, was screaming his name. I opened up the installation manual for the washer--and it was still in an sealed bag, so much for following instructions--and saw that the walking problem was sometimes caused by the washer not being level.

I can't give an explanation for this behavior that would get much of a grade on a physics exam, but I have an intuitive feeling that vibration causes one leg to lift off the ground and then fall again. Because the leg is on a slope, it ends up in a slightly different location than last night. Repeat!

Sure enough, the washing machine was on a slight slope--and the downslope was north, its direction of migration. By this point, I was about to join my wife in cursing Scott's name. I leveled the washing machine--and it didn't much care. The washing machine kept saying, "I'm not American, eh?" and heading for the border.

The next step was to call GE Customer Care--and even without putting the phone up to the washing machine, the gal at the other end could tell that it was time for a service call. "Even if it weren't walking, that is not right!" It turns out that the earliest we can get someone out from Boise to look at this is next Tuesday--we are on the wilderness service route, I guess. Perhaps our service rep will arrive by dogsled, wearing bucksins. Maybe our builder should have leveled the washing machine, but that would not appear to be the core problem.

The dryer was a simpler solution--and the joys of good luck. As all of this appliance excitement was going on, a Suburban Propane truck arrived behind the house, on the back driveway. The driver was there to get the serial number off the undergound propane tank, so I asked him to check the dryer. (It runs on gas.)

Two problems: the gas valve behind the dryer was closed--making it rather difficult to dry clothes. The second problem was that the hose that connects the back of the dryer to the external vent was not hooked up, spewing lint on to the floor.

Now, my builder's excuse for the gas valve being closed was that this is a safety issue--you never turn that on until someone has moved in. Well, perhaps, but he knew we were moving in, and should have had that on his checklist.

I was prepared to believe that the hose pulled loose from the back of the dryer when the Suburban Propane guy pulled it out from under the counter--but when I climbed back there to hook it up, I noticed that the airplane clamp that holds the hose to the back of the dryer was so loose that it could not ever been connected. Groan.

Jetted Tub

I soaked my poor aching back in the jetted tub, and in spite of my initial concern some weeks ago that the jets weren't powerful enough for what we paid, I have changed my mind. They are powerful enough to provide some massage to sore muscles. But then I noticed that only three of the six vents were operating--and at least two of the round knobs above the water line that control the jets were just spinning freely, turning nothing.

So I called up WhirlJet, the maker of this tub. We have been in their factory showroom near Boise. The warranty service head at first claimed not to recognize this type of control as being a WhirlJet tub. I explained that we bought it at their factory showroom. Then I found the web page where our particular model appears. When last we talked on Thursday, she was insisting that the jets are controlled by a round flange around each jet. If so, I'm confused, because none of the flanges turn as she indicated that they should.

Aggravating matters is the water now has a faint greenish tinge--which from what one web site that I found (and have since lost) indicates, sounds like copper in solution, aggravated slightly acidic water sitting in pipes in warm weather.

Backup Generator Does Work

We had a lovely electrical storm last night--and we lost electricity briefly--and within a second, the backup generator had started up, and replaced the missing current. While not a problem for appliances to lose power for a second, desktop computers don't like that. It is probably time for uninterruptible power supplies for the desktops.

Last house project entry.