Take two function generators, an old CRT oscilloscope, a couple of power and BNC cables, and look! Whirling, dancing lissajous figures!
Chunky knobs! Clicky buttons! Drifty outputs! Squiggly curves!
Lissajous Figures
Author: Brian Garthwaite
Bespoke Breadboard
Need a thing, but can’t get it in the right size, right shape, right odd set of dimensions? That’s one reason to keep a workshop in the basement. If we can possibly make it, we’ll certainly try.
Pictured: a custom optics breadboard, for a very specific apparatus, with many, many drilled, tapped, and cleaned 1/4″-20 mounting holes. It’s big, and shiny, and has a bright future ahead!
Probably with lasers or something. Lots of lasers around here.
Crookes Radiometer
Here in the basement, we have all sorts of curiosities. (Hence this strange blog.) Among them, a Crookes radiometer happily spinning in the sunshine. It’s a delight on these crisp, clear, wintry mornings.
The short version: inside a partial vacuum, little black-and-white vanes sit atop a low-friction pivot. When heated, typically by sunlight (but a flashlight will do), it begins to spin, as if propelled by an invisible thrust from the black sides of the vanes. We’ve been told it’s a process of thermal transpiration that makes this happen, but no matter what, it’s oddly hypnotic.
Posters
New decorations for the student lounge. courtesy of one of our radio astronomers. Come to think of it, we have a lot of radio astronomers.
Radio telescope arrays really could use some cooler names.
January Snow
And we’re back from break. Snow!
Extremely Fragile
No kidding. Bright red indicator to proceed with caution.
Purple
The color for next semester’s toy kits: violet.
Perforations
Old texts from the library sometimes still have these perforated markings, ensuring that no one forgets that this particular copy of Morse’s Vibration and Sound, from the International Series in Pure and Applied Physics, isn’t the same one that Grandma’s reading for her book club. They’re kind of charming in their own way, a means of labeling texts that disappeared at some point.
Presumably the librarians could enlighten us on that point, were we to ask nicely.
In the meantime, we’ll just muse over the idea that for a time, some individual had to take every new acquisition and punch a few of these before the first shelving. Some dedicated machine sat on a desk just for this purpose. And when it was a big day, those little punched-out chads probably got everywhere. The spilled glitter of their day.
It’s Always Sunny…
We have several murals on display at the Observatory for those with time to look around. That includes ol’ Helios here, with a real Mona Lisa smile going on.
Leonids
Ninety years ago, during the Leonids meteor shower, someone was counting a lot of burning bits of debris from comet 55P/Tempel-Tuttle. With one fifteen-minute window boasting forty-five meteors (!), that’s a powerfully active shower. Not quite a storm, but those happen with the Leonids sometimes.
According to NASA, the Leonids peak about every 33 years, with 1966 being a spectacular meteor storm. In one fifteen-minute window, thousands of meteors fell like glowing rain. How amazing is that?
Also: check out the times indicated. We’re assuming the counting started at 11:00pm and ran until early morning, with a 24-hour clock opposite how we’d expect it. (Maybe sleep deprivation?) Either that or it was a truly spectacular meteor shower!