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.
Our Observatory is the second on campus, a replacement for the 1887 original. That one was constructed to house our antique Clark refractor telescope, an early gift from William Bucknell, because it’s really not the sort of instrument you set up on the front lawn when the skies are looking decent.
Here we see the building’s layout as of June, 1959, presumably as discussions were underway regarding the renovations that would begin in 1962. During which one of these walls would collapse, necessitating a relatively hasty pivot to create the current Observatory to maintain the astronomy program. (We’re very grateful for that, sixty years later.)
Should we expect restrooms in an 1889 structure? Which way is north? Did the individual drafting up these plans just not like drawing doors? What’s that unlabeled space “south” of the office? When transitioning a class from the classroom to the observation dome upstairs, do you lead the students through your office or make them go outside? So many questions.
Our wonderful Clark refracting telescope support column, in all its masonry glory. Structurally isolated from the rest of the building so that footsteps don’t cause wobbles in the telescope’s field of view.
For the most part, the light accumulation of dust, pollen, and other stuff on the objective lens of your telescope is a thing you live with and ignore. The damage you can do to the lens and its optical coatings is far more severe than the minor loss of image quality from tiny flecks. Known and accepted trade-off.
Here, however, we have a classic TeleVue Renaissance that’s still in good shape. Aside from the dust and dead spiders, anyway. Exact age is unclear, but we can roughly place it between TeleVue’s founding in 1977 and the construction of the “Halley’s Comet” models in 1985. Serial number 1100, for anyone keeping track at home. Even dust-covered, the optics appear good at a quick glance, and they have a reputation for remaining in good shape for a long time.
There’s a bit of chromatic aberration when you look closely, an issue which has been resolved in their current models. (Optics = hard.) The design type is called a Nagler-Petzval, which uses a pair of lens doublets to correct numerous distortions caused by refraction. Every design has its pros and cons; this one’s quite nice. Our version has – we think – an air-spaced doublet (two lenses utilizing different curvatures) as the objective, and a cemented doublet in the rear.
At least, that how the Halley’s Comet edition was made. The current optics update utilizes two air-spaced doublets – see the diagram for the NP101is – so it’s reassuring to see that the improvements are incremental. Good sign for the one we have.
Okay, the brass could’ve aged better, but it’s got character!
Needs polish.
Black on brass looks good.
Nice touch.
Even the knurled knobs on the focuser are brass. We don’t want to leave this for display, however. We want to see the stars!
Eesh.
That dust, though.
Speckly.
Yeah, definitely a problem. A cleaning is in order.
Can’t make it worse, right?
Not pictured: the dead spiders removed with air from a bulb blower. Dead spiders do not improve optical quality.
Red goo.
Here, we’re applying a coat of First Contact polymer cleaner, an expensive but effective treatment for safely removing gunk from precision optics. Comes in a wee bottle like it’s nail polish and smell like nail polish remover. Because it’s got acetone and other solvents in it.
Drying before removal.
Once it dries, that little tab lets us pull away the pink film with all of the dust and debris stuck in it. A good time to wander away from the stink of volatile solvents and get a cup of coffee.
Much improved.
And, well, that’s a substantial improvement.
Water spots. No dust.
It’s not perfect. The polymer is very good at removing particulates, but less so at water-soluble stuff. Once we evaluate this with a camera setup, we can see if a follow-up cleaning with deionized water is necessary.
Big improvement.
Problem there, of course, is that we run the risk of introducing tiny scratches in the process. Could be worthwhile if the effects are still visible, but we’re still erring on the “do a minimum of harm” side of things.
Despeckled.
Will it live up to its potential as an imaging ‘scope? Maybe. There’s a fair chance. If not, we’ll keep it around as a stylish yet usable throwback for visual observation. The best telescope, as they say, is the one you use.
In 1991, the Astronomy Club had clearly grown tired of plain walls at the Observatory. With a fantastic mural adorning the interior stairwell to access the Clark telescope (subjects of future posts!), the regular hallways must have looked… fine.
Prof. Dave Lien was the faculty member overseeing all of this, and in April the club had decided a scale version of the solar system would look pretty great. Time to check in with the Art folks!
(Also: “Observing, etc.”)
Just a few-AU-long stretch.
And you know what? It’s way better than white walls! The final design ended up being different from the proposed idea, though the concept is the same. The Sun occupies a place of prominence, and the mural includes both scaled sizes and scaled distances of our solar system, shown side by side.
Not both at once: in that case, it either wouldn’t fit in the building or the planets would be so tiny you couldn’t see them. Both of which really defeat the purpose. (Not that they aren’t fun demonstrations in their own right!)
January, 1997.
Five and a half years later, ta-da! After a quarter-century, several building repaintings and a recent renovation, it still looks sharp.
FOR RELEASE: February 1, 1971; FOR KEEPSIES: In Perpetuity
Do you ever set aside some papers, because you don’t need them right now, but they were maybe interesting for later? And then eventually there’s just a pile or folder or shelf devoted to these, because you’ve inadvertently started a collection? And then, half a century later, someone stumbles across these boxes and wonders, why?
Why do we have boxes of printed press releases from NASA in the early 1970s? Probably the same reason we have old math exams from the 1940s out at the Observatory. (That’s a post for another time!)
Honestly, if we’d been diligent about tidying this stuff, this blog would be way less interesting.
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.
