2023: Go East, Old Folks

McDonald Observatory

February 16-17

Welcome to the wide open spaces.

Our next target was Texas. It's big enough, surely we could hit it? On our last trip there, we were scheduled to visit the McDonald Observatory with tickets to a special viewing thru their 36" telescope. But for various reasons, we never made it there. This time, I was able to snag tickets once again -- the special viewings don't occur that often -- and I planned our departure around that date.

We checked into the Davis Mountain RV Park which was basically just a big dirt patch, but it had all the hookups we need. And not many neighbors. And a nice sunrise witnessed by Mike.

On our first day, we attended a solar viewing and lecture at the observatory visitor center. Shannon, the host, fire-hosed us with information about the sun, what sunspots are and how they form, solar flares, the sun's complex electromagnetic field, and gobs of other related subjects. I only wish I could remember a tenth of it all!

Javalina herd.

After the solar viewing, we boarded a small shuttle bus for a tour of two of the larger telescope buildings. As we were walking out to the shuttle, we were greeted by some of the natives.

Before we started the tour, we took a few quick snaps of the incredible views from the 6800' elevation. I was glad I'd brought my parka.

Harlan J. Smith telescope building.

Our first stop was the building housing the 107" Harlan J. Smith telescope. Our guide Shannon stood under the enormous instrument and once again inundated us with facts. Mike was most interested in the fact that only a one-half horsepower motor is needed to move the giant, due to a counterweight which keeps the 160-ton mechanism in balance. The 107" mirror alone weighs nearly 8 tons!

My chemistry ears perked up at the method they use to clean the mirror, a few times a week. They spray CO2 (liquid in high-pressure containers) onto the mirror surface, forming dry-ice "snow" which picks up any dust on the mirror and evaporates it away, since dry ice not under pressure evaporates directly into a gas.

Also file under chemistry: re-coating the mirror with aluminum, which they do every few years. First they haul the 8-ton mirror out of the telescope (I don't remember how) and use a corrosive agent to remove all the coating. Then they place the mirror in a vacuum chamber and run a powerful electrical current through thin aluminum filaments. The aluminum is instantly vaporized and forms a coating on the mirror only a few atoms thick.

Don't you wonder how people figure this stuff out? <*crickets*> Just me? Okey-dokey, then.

Final stop on the tour was the building housing the whopping 433" Hobby-Eberly telescope. By this time, my eyes were crossing and my legs were buckling. Additionally, this one was less visually interesting, since it's not an optical telescope but just a giant floating mirror used primarily for spectroscopy. All we could actually see was a huge steel-girder structure that holds the many mirrors in place -- this one is waaaay too large to be a single mirror, so it's made up of 91 hexagonal mirror sections.

This giant is so exclusive that researchers never actually come here. They submit their research proposals and if accepted, the two full-time onsite staff perform the research and submit the results remotely.

I was now super-primed for the main event the following evening, the special viewing on the 36" telescope. Not nearly as big as the Big Boys, but still.

Alas, it was not to be. If the stars were aligned, an 80% cloud-cover made sure I wouldn't see any of them. The Universe sent me one more message -- I'm hiding from you!

Mr. U made a half-hearted attempt at reconciliation as we drove out of the mountains, by showing us some nice views and unusual rock formations.

I was unmollified.