Advantages of Having a CNC Mill

The part that holds the diagonal mirror in a Newtonian reflector is called a spider. (It has either three or four legs and a body in the middle.)

I replaced the 1960s antique Edmund Scientific spider (which had no collimation screws) a couple years ago with a very nice modern one that uses four 10-32 screws. I have never been very successful at collimation of the main mirror. When trying to diagnose the problem, i noticed that the round part through which the four 10-32 screws pass had a stripped thread.

The screws go through the round part to tip the mirror holder relative to the optical path. Obviously a stripped thread is not going to do that very well.

Fortunately, the round part with stripped screw hole was a pretty easier part to machine. The original was 1.53" diameter, .41" thick with five 10-32 tapped holes (four for adjustment; one to attach it to tge mirror holder). I had a piece of .5" thick Delrin which was easy to machine into a copy.

Once I put the new part in the spider, I discovered another nuisance: the torque to the adjustment screws was enough to repeatedly rotate the mirror holder so the laser beam would go everywhere it should except the center of the main mirror.  The only solutions would be to add a lock nut to the mirror holder where it connects to the shaft or figure out how to make the adjustment screws zero friction through the center piece. I already had it in the tube, so i adjusted for center on the mirror,:rotating the mirror holder back each time to get back to mirror center.  The final collimation step only requires turning wing nuts on the mirror cell. If I have occasion to remove this again, i may tackle one of these fixes. For now, the mirror is collimated.

Microplastics: How Much is There Really?

A recent study discovered that nitrile gloves were adding to the microplastics measurement. From Analytical Methods:

Quality assurance and control measures – including wearing gloves when handling laboratory materials and samples – seek to reduce overestimating microplastic abundance. However, commonly used laboratory gloves release non-volatile residues, including stearate salts, that exhibit vibrational spectra similar to microplastics. In this work, we illustrate that dry surface contact with nitrile and latex laboratory gloves can cause overestimations of microplastics (mean 2000 false positives per mm2) when using traditional library matching approaches.

Is there an actual problem with microplastics.  Likely less but how do we really know. A little panic goes a long ways 

Scientific Evidence of What Those of Us Saw Who Worked in Cubicles When Corporate Takeovers Happened

 3/2/26 Cornell Chronicle:

Employees who are impressed by vague corporate-speak like “synergistic leadership,” or “growth-hacking paradigms” may struggle with practical decision-making, a new Cornell study reveals.

Published in the journal Personality and Individual Differences, research by cognitive psychologist Shane Littrell introduces the Corporate Bullshit Receptivity Scale (CBSR), a tool designed to measure susceptibility to impressive-but-empty organizational rhetoric.

“Corporate bullshit is a specific style of communication that uses confusing, abstract buzzwords in a functionally misleading way,” said Littrell, a postdoctoral researcher in the College of Arts and Sciences. “Unlike technical jargon, which can sometimes make office communication a little easier, corporate bullshit confuses rather than clarifies. It may sound impressive, but it is semantically empty.”

Although people anywhere can BS each other – that is, share dubious information that’s misleadingly impressive or engaging – the workplace not only rewards but structurally protects it, Littrell said. In a work setting where corporate jargon is already the norm, it’s easy for ambitious employees to use corporate BS to appear more competent or accomplished, accelerating their climb up the corporate ladder of workplace influence.

Corporate BS seems to be ubiquitous – but Littrell wondered if it is actually harmful. To test this, he created a “corporate bullshit generator” that churns out meaningless but impressive-sounding sentences like, "We will actualize a renewed level of cradle-to-grave credentialing” and “By getting our friends in the tent with our best practices, we will pressure-test a renewed level of adaptive coherence.”

He then asked more than 1,000 office workers to rate the “business savvy” of these computer-generated BS statements alongside real quotes from Fortune 500 leaders. Divided into four distinct studies, the research verified the scale as a statistically reliable measure of individual differences in receptivity to corporate bullshit, then, through use of established cognitive tests, made connections between receptivity to BS and analytic thinking skills known to be essential to workplace performance. 

I Think Zero-G Reproduction Has Far More Serious Concerns

4/1/26 Smithsonian reports that experiments suggest sperm may not be successful at fertilization in zero gravity:

Near-weightlessness “causes [sperm] to flip around, to go upside down.… They don’t really know which way is up or down,” Nicole McPherson, a study co-author and a biologist at Adelaide University in Australia, tells the Guardian’s Tory Shepherd. The cells do “not really understand or know which direction they’re going in.”

I would worry also about proper bone and muscle development in utero. I think even under lunar gravity this should concern us. I remember reading in my youth about chickens raised in centrifuges having larger and more developed hearts and legs. I would worry about the opposite problem with babies carried and born in below 1 G environments. 

"Only a Screwdriver Turn Away" Japan's Nuclear Capacity

3/31/26 South China Morning Post:

"Japan has enough plutonium to make 5,500 nuclear warheads, PLA Daily says"

I can see why China is concerned. If the PRC decides to invade Taiwan and Japan steps in, Japan could probably destroy the PRC's military capabilities without assistance from the U.S. It would certainly cause thermonuclear war. This alone will discourage China doing something stupid like invading Japan.

Doom and Gloom From TDS-Suffferers Seems Not to Be Working

The doom and gloom crowd about the Irsn war (most notably at the Wall Street Journal) seems not to be working. The DJIA yesterday was up more than 2%: 1/2% today so far. 

It seems to me that Trump has given the Europeans some defense from Iranian IRBMs landing on their cities. Now, if only they could see their way to protecting their oil supply through the Strait of Hormuz. But they can rely on us to do all the heavy lifting while they mollify their Muslim populations.

I Wonder Why This is Not Getting More Attention

 3/30/26 Union-Bulletin:

LOS ANGELES — The case of a lifetime started with a putrid smell and a green garden hose sticking out of the side of a supposedly vacant warehouse in California farm country.

Inside the sprawling building on I Street in Reedley, code enforcement officer Jesalyn Harper found vials filled with liquid — some marked in English or Mandarin, others with just a code — that bore frightening labels such as “Malaria,” “COVID-19” and “HIV.” Refrigerators, lined up in columns along a wall, had labels that read “blood” and “Ebola.”

As she walked deeper into the warehouse, passing lab workers filling pregnancy test kits, she located the source of the smell that had brought her there — droppings from 1,000 lab-tested mice, she told The Times during a recent interview. The workers were nice enough, she said, but when she started asking questions she could feel the mood change.

“I realized I’m in trouble, and I need to get out of this building without tipping them off that I’m scared,” Harper said.

Her discovery blew open an elaborate criminal case with ties to California, Las Vegas and China. The investigation in Reedley found that the lab was part of an elaborate scheme to import COVID tests from China and pass them off as American made.

But there are some who fear the operation was much more complex than that. A congressional committee uncovered payments topping $1 million made to the operator of the Reedley business from banks in the People’s Republic of China.