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.
Five bucks.
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.
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:
I see stars! And light pollution!
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.)
Note: one particular starveryvisible.
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.
Whoa. Fisheye.
Including the occasional technician out on maintenance duty. Wave hi!
Tucked away in a back corner – we have so many of those – sits a set of the architectural plans for the Tressler Observing Laboratory from 2014. What had once been an exterior deck is now, thanks to a very generous gift, a fully enclosed structure housing six telescopes. On a good night for observing, or astrophotography, or simply appreciating the wonders of the cosmos, the building’s roof slides away, revealing the night sky. It’s a neat trick.
The plans are a (recent) historical artifact, a little water-damaged, but still fully readable. Nothing much in here you can’t just walk over and see in person, of course. For those with an architectural inclination, though, skimming through detail drawings is an always-interesting pursuit.
Astronomy at Bucknell is not just for the undergraduate students, but for the wider community, too. With a whole slew of telescopes to explore the skies, the department sometimes runs family nights and other outreach programs. Local families, summer camps, and others can – weather permitting – have the opportunity to explore constellations, deep sky objects, planets, and sometimes even the crater-riddled surface of the moon.
For those at home, an ordinary pair of binoculars works quite well for that last one. Pick a night when the moon is between new and full, and look to the transition zone between the light and dark sides. The light rays raking across the surface dramatically emphasize the texture. The full moon’s straight-on illumination is less compelling, and, well, there’s not much to see on the new moon.
In order to help explain the skies to the public, the Observatory has a planisphere, built by one of the University’s Presidential Fellowship students with the help of the shop techs. A flattened portion of the celestial sphere rotates, enabling a view of the major constellations at any day and time throughout the year. Polaris, at the center, stays steady while the rest of the sky spins about.
For added excitement, a series of colorful LED lights ring the perimeter, making the stars and imaginary constellation lines glow in the etched acrylic.
There are a wealth of options when choosing a telescope. Refractor (lens), reflector (mirror), or catadioptric (both)? How large an aperture (because letting in more light lets you see fainter, more distant objects)? Manual or computerized control? Optical viewing, astrophotography, or both? Alt-azimuth or equatorial mount? And so on. Dedicated astronomers can get deep in the weeds on the finer details.
What they all have in common is a BIG WARNING often in BRIGHT RED ALL CAPS that you should never, ever, point your telescope at the Sun. It’s solid advice.
Looking directly at the sun with your naked eye is likely to cause permanent eye damage. Doing so with the extra light-gathering power of a “light bucket” only accelerates the problem. Even if you don’t peer through it, the heat that builds up within the telescope’s delicate optics is enough to irreparably damage them and ruin your very expensive equipment. What’s an aspiring solar astronomer to do?
Find a solar telescope, of course. A few special features make this telescope safe for solar viewing (and somewhat less useful for anything else). It has a very small aperture, because it really isn’t necessary to collect more light from the brightest thing in the sky. It has a small section of opaque glass on top of the telescope which shows a pinpoint of light when the sun is approximately in view. And, best of all, it has an narrowband filter around H-alpha.
H-alpha is a specific wavelength of light emitted by excited hydrogen atoms, about 656nm, and the brightest hydrogen emission in the visible wavelengths of light. It’s quite red. It’s also, through a suitably narrow filter, something you can safely observe with your eyes. Pare away the other visible light, all of the UV and IR, and you’re left with the sun. Red, intense, and through the proper set of optics, magnified so that you can see amazing things.
Prominences erupting from the surface. Dark filaments that indicate region of magnetic shear. Sunspots and flares. The speckled, roiling surface of a star that’s like an orb of churning lava. It’s very cool. Astronomy you can study without staying up all night.
