Tuesday, August 11, 2009

Heroic engineering

About 30 miles northeast of the seaside town of Carlsbad, the peak of Mount Palomar rises a mile above sea level. For California, this is a long distance between the first coastal mountains and the sea, and the local plant life of scrub and chaparral is accustomed to a dry climate. While the land to the west is San Diego County, home of some of the best weather in the world, the mountains take for themselves the last of the ocean moisture, and to the east lies the start of the great desert of the southwest.
Mount Palomar is most famous for the Mount Palomar Observatory, a privately held temple of science that is affiliated with the California Institute of Technology, known usually as Caltech, situated many miles north in Pasadena.

The observatory was built between the wars, in an age of heroic engineering. Taller buildings, longer bridges, bigger versions of everything, including telescopes, were goals that seemed natural to attain, and often were taken to the limits of the knowledge and techniques of the engineers of the day. George Hale is given credit as the father of the great observatories of southern California, both Palomar and Mount Wilson, and he gets the singular honor of having the telescope itself named after him, the mighty and magnificent Hale Telescope with its 200 inch mirror, at the time the largest in the world.

The huge structure must be mobile to allow the telescope to point to anywhere in the sky, and these clean metal wheels behind glass are as large as the steel wheels on locomotives.

There were several illustrations with captions that explained the workings of the machine.

And then there was the machine itself, both massive and precise. My digital camera, programmed to recognize faces, mistook the astronomer's cage at the top of the telescope for the face of a giant robot.

We arrived just a few minutes late for the guided tour, which you can see here up on the catwalk that circumnavigates the dome. The guide was talking about the most recent controversy that made it to the public's attention, the re-categorization of Pluto from a planet to a planetoid.

There are more telescopes on the peak of Palomar that just the Hale. In 2003, the 48 inch Samuel Oschin telescope was instrumental in discovering Sedna, a planetoid about half the size of Pluto and currently about twice as far away from the sun. All things that orbit the sun have elliptical paths, but Sedna's is much more severely elliptical that any planet's orbit. It takes about ten and a half millennia to complete an orbit, and it is currently very close to its perihelion, the closest point from the sun that the orbit achieves, and even that is far outside the orbit of Neptune, the most distant of the true planets.

During the construction of the observatory, the 200 inch mirror was one of the last things put in place. The engineers needed something roughly the size and shape of the mirror to put in the mechanism to make sure it could be moved around and aimed properly, so they had this massive round slab of concrete made to be the stand-in for the mirror.
Two full grown men stood on the concrete slab to give an idea of scale. The young fellow on the right is Nick Rose, son of Ken and Mishell Rose, my gracious hosts on the first leg of my Southland vacation this year. The fellow on the left says he has something to do with this blog, but no independent verification of his claim could be found.


ken said...

Oops. Perihelion is the close point, not the far point, so Sedna's present distance of something like 7 billion miles makes it nearly as bright as it ever gets now, and even so, you'd need to be looking through the 100inch telescope on Mt. Wilson to have a chance of seeing it with your eye.

Matty Boy said...

Thanks, Ken. I made the fix.

ken said...

Except you made it wrong. It is near perihelion, and nearly as bright as it'll ever get. And you'd still need the 100 inch to see it with your eye.

Matty Boy said...

Thanks again. I misread the picture and thought it got inside Neptune when it got ti its closest point.

My bad.

ken said...

No sweat. We still luvz ya. Dini wants to shed on you some more.