Making an ‘X’ across your telescope’s eyepiece is a handy thing, letting you mark the center instead of eyeballing it. There are all sorts of reasons you might appreciate that little bit of assistance, provided it doesn’t actively interfere with seeing things. So you use as fine a wire as you can. Which is going to break, of course, so keep some spares in the desk drawer.
How thin? This is AWG 53, all of 0.0007 inches thick (0.0178 mm). Enough to make even the finest human hair seem chunky in comparison.
An electronic buzzer buried inside a foam ball, on a long cable with a switch and handle at the end. Flick the switch, and a piercing 2,500 Hz signal begins. Whirled in a big circle around your own head, the tone persists. For everyone else in the room, it creates a cyclic Doppler shift, a repeating weeee-oooo, weeee-oooo that sticks in the brain even after it’s done, like when you see phosphene images behind your eyelids after catching a glimpse of something way too bright.
We can’t overstate the wonderful modifications to the original object, back in 2010, which added the cable and switch. Your bog-standard Doppler ball – available from several scientific apparatus purveyors – requires one to open up the ball, turn on the buzzer, then close it back up. Tossing it back and forth between students illustrates the concept.
Then, when you’ve had quite enough and just want it to stop, you have to pry it open and shut the whole thing off. (This vintage version, pre-mod, required full-on battery removal.) The Doppler ball: it teaches us all kinds of new lessons!
From the days before planetarium software was readily available, we have an intense glut of celestial globes, which show the positions of the stars and constellations on the night sky. Also the day sky, of course, but unless you’re watching a total solar eclipse they get lost in the bright blue light scattered by our atmosphere. They get little use except as office decorations.
We have two Earth globes – one is a giant, inflatable beach ball – which still get regular use in Astronomy classes. Unsurprisingly, visualizing the movement of an Earthbound observer on a tilted, rotating, orbiting planet around the sun isn’t always intuitive. Having a mini-Earth to look at helps immensely.
We also have a very nice lunar globe, which really should see more use. It’s highly detailed, including on the side of the moon that only a handful of humans have ever seen. (More craters, fewer mare.) If you dig maps, it’s a very cool map.
Scale 1 : 8,533,150.
And when did this charming item come into being? 1969, of course.
You can’t tell from the photo, but the tone is lovely.
Both Physics and Astronomy courses do a lot of work with waves, and while light is one of the most important types for study, sound is exceptionally handy for demonstrations. There’s an immediacy, a feel, that can make sonic demos feel more intuitive.
We have a few of these about, metal bars with supports at the nodes of a standing wave, seated over a wooden box. The string goes where the bar doesn’t vibrate, and hence doesn’t dampen the sound, while the box helps it resonate louder. Ka-bong! They’re quite fun.
Quality!
And, yes, Carl J. Ulrich of Minneapolis, Minnesota did some fine work here.
Once upon a time – for a good long while, in fact – mathematics and astronomy overlapped. Now, of course, astronomy is considered more appropriately physics-adjacent, and mathematics would like to make it clear that while they share a department with statistics, the two really are their own, distinct fields.
Then there’s the fuzzy boundary zone between biophysics and applied mathematics and mechanical engineering…
In our attempts to minimize the ever-growing aura of light pollution around the Observatory, we work to form good relationships with our neighbors. And to maintain them.
Back in 1979 – an excellent vintage! – the Keystone Water Company agreed to a switch controlling the light outside their standpipes, just south of the Observatory. For as long as we remain good stewards of the switch, always turning it back on when we’re done observing, they let us adjust the night sky’s brightness just a little bit more each night.
Your average TA for an Astronomy night lab is excited about their job. They not only took an Astronomy course, but liked it enough to come back. At night. Irregularly, as the weather permits, sometimes in the cold of a Pennsylvania winter. They’re enthusiastic about their job. We’re enthusiastic about them.
Good question!
So when you find notes from almost three decades ago with student gripes? Totally understand. We wish every student could bring the same excitement to a night with telescopes and stars.
And, for the record: Saturn absolutely is beautiful through a telescope on a night with no moon. Just phenomenal.
As we prepare for the next major solar eclipse in North America – mark your calendars for the 8th of April, 2024! – it’s fun to look back at Observatory records from previous eclipses. On May 10th, 1994, nearly 300 people congregated at the Observatory to take in the spectacle of a partial eclipse.
It’s worth noting that getting the full experience of totality requires a perfect combination of timing, location, and decent weather. Not simple.
This particular event was an annular eclipse, in which the moon’s apparent diameter was less than that of the sun, so that there was always a portion of the sun’s disc visible, creating an annulus (ring) when viewed along the path of greatest eclipse. Still amazing.
In 1963, one could purchase a Standard Astro-Dome with a 17′ inside diameter for the low, low price of $14,667. It must have been a worthwhile investment, because we’re still using it 60+ years later with no plans to update or replace it anytime soon.
