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.
