Touring the 4 Meter

After a good nights sleep, I awoke in time to have a late breakfast at the observatory dining hall. After that, I spent some time just wandering around the mountain top, taking in the general layout of the place and looking inside some of the domes that had visitor galleries. Around 1:30pm, I stopped in at the visitors center and learned that at 2 o'clock a tour of the largest scope on the mountain, the 4 meter (158-inch) Mayall Telescope, would begin. I spent some time looking at the various exhibits in the center. By about 1:45, a group of folks had arrived for the tour, and shortly thereafter, our guide showed up and led us up the hill to the dome of the 4-meter scope.

This is a very impressive telescope! The yoke that is the polar axis bearing is HUGE! At the time it saw "first light" in  1973, it was the second largest telescope in the world, with only the 200-inch at Palomar being larger.

The photo to the left shows the huge blue polar axis yoke, the white truss tube, and the secondary mirror assembly.
This scope is of the Ritchey-Chretien configuration, which is optimal for providing the widest flat optical field.

Following the tour of the 4 meter, I went back to my dorm room to have a quick cat-nap before dinner.

During the evening meal, I had the luck to be seated at the same table as a group of visiting astronomers from Ohio who were there for an observing run on the 4 meter! I mentioned that I had just toured that dome. They told me that they were collecting data on metal-poor globular clusters


Following dinner, I made my way back to the visitor center to kill some time before the evenings public observing program started.