From a recent finder, there is a 5$ suggested donation to tour the visitor center. If you do not want to go into the center, you should be able to get to the GPS coordinates by walking up the hill for free.
How far is the Moon from the Earth?
Are there other planets around other star systems?
What is a black hole?
Can a black hole devour a star?
Are there asteroids that could pass by the Earth?
These are several interesting questions now being explored at the McDonald Observatory.
The McDonald Observatory, a research unit of The University of Texas at Austin, is one of the world's leading centers for astronomical research, teaching, and public education and outreach. They have several telescopes there for studying the stars, other galaxies, or various space phenomenon. There is a free viewing area to look at the telescopes during the day. Surrounding the telescopes are small houses for visiting scientist to sleep during the day so that they can work when it gets dark. Also from here, you can get a great view of the desert below.
To get credit for finding this virtual cache, read the large dedication plaque in front of the McDonald Observatory at the GPS location and e-mail me the year on the very bottom right of the sign.