The trip is from Natchez Trace, Tennessee, to Dodge City, Kansas, by way of Tucson, Arizona.
McDonald Observatory, Davis Mountain, Texas
Leaving Davis Mountains State Park the next morning after the wind had died down, we drove north-west on Hwy 118 to the McDonald Observatory.
Reasons for choosing this site for an observatory was the lack of light pollution, the clarity of the air, and the height of the mountain. Which meant the mountaintop provided quite a view.
This was a working observatory, affiliated with the University of Texas at Austin, but it was open for tours. First stop was an auditorium in the visitor center where live images of the sun were projected onto a large screen. Naturally, this was live minus the 7-8 minutes it takes light to reach us from the sun. Our tour guide pointed out the solar features we were viewing, such as flares and spots and prominences. Then it was off to see the first of two telescopes.
Inside, it was cool. She explained the observatory is kept at normal nighttime temperatures to prevent fogging of lenses when the dome was opened for viewing.
This was a traditional telescope, with a 107-inch reflector, which could be maneuvered and aimed at whatever the astronomer desired to see. Additional equipment could be installed on it, depending upon what the astronomer was wanting to study.
There are no longer eyepieces to look through. Everything is done by computer.
Astronomers submit the projects they want to use the telescope on. A board of scientists in charge of the observatory decide which projects are worthy and prioritize them according to what they feel is most urgent or useful. There are barracks for astronomers to live in while their projects are being carried out. But nowadays most astronomers don’t even stay on site. Their projects are carried out for them by astronomers on staff and the results are sent to them via Internet. Our tour guide opened and closed the dome, then maneuvered the telescope all about for us. She could do this since no experiments were being carried out at the time. They take place at night, of course.
Next, we boarded a bus and it was off to the second telescope.
This was the newest telescope, with a radically different design.
It could not be aimed like the other telescope. Its design incorporated 91 meter-sized hexagonal mirrors mounted on a frame to give an effective collection area 8.5 meters in diameter. At a fixed altitude setting of 55 degrees, almost all objects in the northern sky are accessible when the telescope is appropriately turned on a vertical axis. In other words, it remained pretty much stationary and captured images that passed directly over it. But with 8.5 meters of reflecting surface, it was much more powerful than the other.
The tour was well-worth my time. This was the one and only time I’d ever been in a working observatory and the tour guide was very informative. I highly recommend it if you are ever in the area.
The next Location is Guadalupe Mountains National Park, Texas.