Discoveries in the Physics & Astronomy shop | Science, curiosities, and surprises
Do not attempt to clean expensive optical equipment with the same things you use to clean your nose.
Remember: instructions that seem to lay out the most common-sense directives – on signage, in user manuals, in a specification document – are sometimes the result of people actually doing those questionable things.
You can bet someone tried cleaning a telescope’s eyepiece with the handkerchief from their pocket.
Meteorites – those shooting stars which don’t completely burn up entering our atmosphere and then crash to the ground – can be made of all sorts of stuff. The most commonly found in museums and collections are metallic, not because they’re the most frequent type of meteorite, but because they’re the most likely both to survive entry/impact and to be discovered. A stony meteorite might look remarkably like an ordinary rock. A big chunk of warped iron just sitting on the ground? Slightly more conspicuous.
We have a few meteorites and pieces of meteorites on display, including this big slab. Cut, polished, and given an acid treatment, it shows off its internal crystalline structure. Primarily iron and nickel in two different crystalline shapes, it has a characteristic pattern known as a Widmanstätten pattern. Given a sufficiently long cooling period to enable crystal formation – typically on the order of millions of years – it produces this distinct appearance that highlights its extraterrestrial provenance.
Can’t do this stuff in a lab is what we’re saying.
The acid-etching process enhances the pattern where the high-nickel taenite alloy is more resistant to the acid than the low-nickel kamacite, turning a smooth, polished surface into one that looks, well, really cool.
Stumbled across this little old gem while cleaning the Observatory. Age unknown, could use a little cleaning, but it still mostly works. We’re charmed by all manner of objects around here.
Neat-o!
A great many jobs in the daily work of a shop consist of riffs on this: can you make item A connect to item B? It might be physical connections, electronic and/or digital signals, or even the relatively abstract interpretation of transitioning a lab space over from one experiment to the next without disruption. The simplest ones are when someone can’t locate the proper connector cable. (There are so many different kinds!) Less simple are those times when two things are supposed to fit, but don’t.
Just straight-up don’t.
At the Tressler lab, we have the luxury of permanently-installed piers which support our telescope mounts. For our purposes, this is an excellent improvement over the default, a very stable yet heavy tripod. Now in the process of upgrading our mounts, we find that the tapped mounting holes on the pier don’t match the drilled and counterbored corresponding holes on the custom-made mount adapters. By 1/8″ or more in some cases. Sounds small. Is actually huge. Is will-not-fit-even-with-brute-force huge.
Note: not made in-house. We could try to guess where the error might have arisen, but our job is to fix it.
Also note: the previous mounting plate was not precisely machined to the proper dimensions, either, but was close enough that it was fastened by brute force. Sensing a theme here, which is this: precise measurements are crazy hard.
Getting to the adapter-for-the-adapter called for more than one CNC-milled plastic prototype. Measure, mill, test. Rinse, repeat. Polyethylene, as one might imagine, is cheap stuff.
A few test runs later, we have a custom-machined (in-house!) sheet of 1/2″ aluminum to connect to the 5/16″-18 tapped holes on the pier, which then sets up a new series of 1/4″-20 holes in this plate and the mount adapter to hold everything rock solid. Holes drilled and tapped, counterbored for a clean surface with all of those socket screws.
And all carefully measured and aligned on the milling machine to within 0.001″.
You don’t appreciate the precision of reliable machinery and sharp tooling until the pieces slip together effortlessly. Whoa! Goosebumps!
Best part? The adapter is functionally invisible for anyone who doesn’t know to look for it. Few things feel as rewarding as solving a problem before (almost) anyone else realizes it’s there.
Sometimes you just happen to check the skycam at the most perfect moment. Welcome to October!
Sometimes, stuff just lingers. It’s unclear how long it’s been sitting on this or any shelf, whether it has any use anymore, how on earth to dispose of it, etc. Of course, those odd objects tend to sport some of the coolest old labels.
So much to enjoy here! Buddy the dog, holding a flag with his name, but also helpfully labeled below as “Buddy,” just in case it wasn’t obvious enough. Directions for using metal polish on non-metallic surfaces, which – to be fair – might not be obvious. (Still mostly amounts to wipe on with a soft cloth, wipe off with a soft cloth.) The prime visual real estate for “Non-Inflammable,” which is an entertaining reminder of the flammable/inflammable quirk of the English language. What a country!
It’s not entirely clear if the yellow color was an original choice or has been caused by many years of aging paper.
At any rate, the steel cap is thoroughly corroded shut, so there’s no telling what remains inside. Whether that corrosion is caused by or despite the contents of the Capital Metal Polish container, we’ll never know.
Telescopes don’t work when they’re not at the same temperature as the surrounding air. They don’t work if there is glass between them and the sky. (Okay, they work, just not very well.) So: you use them outside, and any space used to protect them from the elements is best if it’s as much like outside as possible.
Observatory domes, retractable roofs, etc.: all very fancy ways to keep the rain off.
Wildlife has a habit of getting into these spaces, especially the small critters. Spiderwebs are a frequent feature. Birds appreciate the shelter from the elements, and will happily build nests if given sufficient access. It’s amazing what they’ll squeeze through, if for no other reason than to leave a stark white splotch on an all-black telescope. At least it seems that way.
This doesn’t include the exterior-only wildlife population that brightens up the occasional observation session. Nocturnal critters get used to the quiet around daytime spaces, so it’s best to keep alert for opossums and skunks and other adorable visitors when out late at night. That black-and-white blur is probably just a feral cat, but you know what? Best not find out for sure.
The Clark, our lovely 19th-century telescope. Much to be written on it another time, but here’s a picture with the dome open on a fine, sunny day.
Just look at that lovely brass set against the black steel tube. Magnificent.
It’s no surprise that there are books everywhere. This is a university, after all. Books are one of the biggest threads connecting every department and avenue of study.
Sometimes it’s fun to flip open some of the old tomes gathering dust on mostly-forgotten shelves. This was, presumably, a useful reference when acquired in 1973 or so. Flipping open the front cover, it’s not hard to imagine that someone got at least $5 worth of use out of this.
That said, this is not the most compelling cover-to-cover read, unless you’re really into data tables for the sake of data tables. Front to back, it’s tables of lunar positions and times over a span of 2,652 years. From what seems like an arbitrary start – 1,001 is a pretty fine number – to around the death of Johannes Kepler (November 1630) makes for a lot of potential eclipses and other lunar phenomena that would get the attention of ancient writers.
Folks around here are already talking seriously about the solar eclipse in April of 2024. Syzygies are a big deal.
Syzygy. Y-Y-Y. Great word.
Astronomy can be awkward. By necessity, observation happens at night. (Mostly.) And outside, in whatever weather permits clear skies. Hot and humid or bitter cold, the telescopes only function when they’re at equilibrium with the air around. When the temperature drops so low that the grease in the motorized mounts thickens, we call it quits, but nights reaching down to about 20°F are fair game. Precipitation always shuts things down, as does substantial cloud cover.
What to do when you’re at home, all warm in your jammies, and not sure if it’s worth trekking out into the cold? Check the Bucknell University Sky Camera website, of course. If it looks like this:
Visible stars, no serious cloud cover: you’re good to go. The bright spot in this particular image is probably Saturn, but you get the idea. If you can see it here, you can see it through a telescope. Checking the weather forecast is fairly reliable, although it gets dicey around those transition zones between “good enough” and “should have stayed home.” Forecasts also describe cloud cover in terms of percentage obscured, without a distinction between sparse-but-dense and widespread-and-gauzy.
Depending on what you want to accomplish, sometimes clouds are something you can work with. Astrophotography? Visual observation? Naked eye and constellations? Sometimes, here in a Pennsylvania river valley, you shrug and make it work.
(The alternate method is to walk outside and look up – quite reliable, that – but maybe not ideal if you’re in the aforementioned jammies.)
The skycam can also be entertaining to check during the daytime. You can watch the sun track across the ecliptic and see the discrepancy between clock time and solar time during Daylight Saving Time. On a cloudy day, sometimes the clouds themselves are just plain neat. Raindrops. Snow accumulating. Snow melting. Birds and bugs and all sorts of things captured by intermittent photography.
Including the occasional technician out on maintenance duty. Wave hi!