The View Up Here

Random scribblings about kites, photography, machining, and anything else

  • Flickr Gallery

Archive for August, 2014


Posted by Tom Benedict on 15/08/2014

I realize I haven’t written anything in months. I blame work.

Every large telescope relies on mirrors to collect light. And every mirror relies on something shiny to make them work. That shiny bit can be any number of things: silver, gold (yeah, gold), or in our case aluminum. Sometimes these are over-coated either for protection or to boost reflectivity in a particular wavelength range. Regardless, all coatings are subject to another truth about astronomy: it’s an outdoor sport. Mirror coatings are subject to wind, dust, and sometimes rain and snow. Coatings degrade.

Our mirrors are bare aluminum, which gives us a base reflectivity just below 90%. We put about 850 angstroms worth on our mirrors. It’s a little thin, but it’s what our chamber is capable of. Our primary mirror needs to be re-coated every three years. Our secondary mirror, which faces down and is less subject to rain and dust, needs to be re-coated every five years or so. This year they both came due.

The past two months of my life have been spent coating two mirrors.

As simple as that sounds the truth is a lot more involved. The room was completely stripped and cleaned top to bottom about six times. The chamber needed to be re-prepped, once for the secondary and once for the primary. In between I was ordering new supplies, testing our secondary support system for leaks, helping to take apart and re-assemble the telescope, etc. Except for a brief break for our company’s 35th anniversary party and another for a hurricane, I’ve been at the summit for the better part of two months.

Both coatings turned out well. Last night we finally got the thing put back together and aligned. We still have one last chamber re-prep planned for Monday, but other than that I’m off the hook. This morning when I woke up I looked around the room and saw my KAP bag, my camera bag, my gliders, and my 2m/70cm radio, and realized that for the last two weeks I’ve practically had no hobbies to speak of. Everything has revolved around those two mirrors. And now I’m finally free. At least for a couple of years.

Some time soon I hope to get my cameras back in the air, and to start playing with planes and radios again. But for now my only plan is to sleep.

– Tom

Posted in Astronomy | Leave a Comment »