I was lazing in the recliner the other day, idly wondering what on earth I could write about. “Christ, half of that group are far too educated for their own good, and the other half have an attention span measured in milliseconds. What might interest the lot of them for the 90 seconds it takes to read an article?” Well, naked women, of course. That always works. I have to keep my dignity though, and someone from the school might spot my writing. How about “big, complicated machines” then? Yes, that will do, I think.
Since we were recently talking about celestial bodies, let’s take a look at some of the marvelous instruments that astronomers use to detect and image them: great big telescopes.
Refractor telescopes are the oldest kind of telescope, and an image of a Galilean telescope, or spyglass, is what most people imagine upon hearing the word “telescope”. In fact, most people think that Galileo Galilei invented the telescope, but he didn’t. It was invented by three Dutch guys (kinda, sorta), and Galileo just heard about it, and then used it to piss off the Pope. A refractor telescope is basically a tube with a large objective lens at one and a smaller eyepiece at the other. It works by gathering more light than a human eye can gather by itself, focus it, and give the operator a brighter, clearer and magnified view. The objective lens bends or refracts incoming light onto the eyepiece, hence the term ‘refractor’.
Now that that is over with, let us look at the two biggest refracting telescopes: the Lick and the Yerkes telescopes.
The Lick Telescope
The Lick telescope is a 36 inch refractor located at the University of California’s Lick Observatory atop Mount Hamilton in the Bay Area. It was the largest telescope of its kind until 1897. The telescope saw first light in 1889, in which there is an amusing anecdote. The builders had to wait three days after completing the telescope for a break in the cloud cover so that they could test it. When the telescope saw first light, they found that the instrument couldn’t be focused. An error in the estimate of the lens’ focal length caused the tube to be built too long. A hacksaw was sent for and the great tube was unceremoniously cut back to the proper length, after which it focused perfectly. I’d have loved to be a fly on the wall during that discussion, ho ho ho.
What a lovely old photo. It’s much better than any of the current ones. Note how high the eyepiece is above the observatory floor. The floor of the observatory can be raised and lowered with a hydraulic system to get the observer close enough to where the eyepiece can be reached, using the bleacher-like scaffolding you see in the background or perhaps something smaller if you’re lucky. When the observer can finally get to the eyepiece, this is what he has to work with:
Isn’t that marvelous? Such intimidating complexity! When I first saw a picture of this end of the telescope when I was a younger Professor, I was instantly in love. What do all of those handwheels do? How hard do they turn? What is that mechanism around the eyepiece? A film holder of some sort? So many mysteries…
Of course, modern astronomers have spoiled this magnificent visage:
You see? Totally ruined. They even painted it white for christsakes.
In its heyday, the Lick made several major discoveries blah blah blah, a list of which is available on its Wiki page. It is an obsolete instrument now, of course, and is used only for tours and public relations events. I’d still love to take a gander through the old girl though, wouldn’t you?
Next time: Yerkes.