We drove I-10 between San Antonio and Phoenix many times while Sarah was an undergraduate at ASU. “Go Sun Devils”! The McDonald Observatory was one of the points of interest highlighted with signage along the way, and this has stuck in MFI’s memory for several decades. Therefore, as part of her plan for our trip to Big Bend National Park, she also arranged a 2-day excursion north that allowed us to visit the observatory. MFI researched the tour options and made reservations for everything: visitor center, both their large telescopes, and a return at sundown for what they called the “Star Party.” Squeezing everything into one day was impossible, so I made a 1-night reservation at the nearby historic Hotel Limpia in Fort Davis, TX.
Fort Davis is the government seat for Jeff Davis County. It has a population of 1,201 (2010 census), and within its boundaries lies Fort Davis, a designated National Historic Site. The Fort, established in 1854, is one of the best surviving examples of a frontier military post. For 37 years, post soldiers were responsible for protecting emigrants, mail pouches, and freight wagons from raids along the Trans-Pecos section of the San Antonio-El Paso Road. Downtown Fort Davis still has an authentic western, cowboy vibe.
We stayed one night in Hotel Limpia (circa 1912) and checked in before heading to the observatory. Quaint little place.
After check-in, we drove to the observatory atop Mount Locke, the highest point on Texas highways at 6,791 feet. The sky was partly sunny, and the views were beautiful. As seen in the picture of the sundial, we arrived at about 11:45 pm. Our tour of the telescopes didn’t begin until 1:30 pm, so we browsed interactive displays throughout the Visitor Center. I must admit that if I had been a school-age youngster, the displays would have definitely piqued an interest in astronomy. Here is a model of the Harlan J. Smith telescope, and yes, that is a tiny figure of Harlan in the middle.
Like most people, we understand the importance of reduced light pollution to enhancing our views of space through telescopes. We’ve all experienced how the night skies really come alive when we get out of the city glare. We learned that Mount Locke is just a small piece of the Greater Big Bend International Dark Sky Reserve. The Reserve consists of three large Texas counties and three Mexican Counties. As long as people and businesses comply with the lighting restrictions, we all reap the visual benefits.
We began our tour in a small theater next to the Visitor Center. We received a very interesting discussion about the sun. Special telescopes on the observatory grounds were focused on the sun, and we witnessed real-time views of the sun’s surface, sun spots, and a variety of solar flares along the corona. Fascinating!
Our next stop was the HJS (Harlan J. Smith), 107-inch (2.7 m) Telescope. The dimension used in describing telescopes is the diameter of its light gathering mirror(s). In this case, a mirror of this size sees 250,000 times better than the human eye. The HJS was built between 1964 and 1968 at a cost of $5 M and weighs 160 tons. Initially, NASA needed it to survey the planets and subsequently support spacecraft dispatched on missions for more detailed studies. Currently, HJS can be outfitted with many different instruments enabling a variety of astronomical research observations, including the composition of stars, motion of galaxies, and search for other planets around stars in our galaxy. This telescope is still used on every clear night of the year.
The second tour stop was at the HET (Hobby-Ebberly Telescope). The HET was dedicated in 1997 and uses a 91-hexagonal mirror honeycomb to create in effect a 433-inch (10 meters) mirror. HET is the third largest optical telescope in the world, weighs 80 tons, and moves on cushions of air, which allows viewing of 70% of the visible sky. HET receved a $40 million upgrade in 2016.
This telescope is conducting the DEX (Dark Energy Experiment), the first major effort to search for dark energy in the early universe. Dark energy is a yet unknown force theorized to explain why the universe expansion is accelereating rather than slowing. To discover dark energy, HETDEX is making a 3-D map of the universe when it was 1 billion years old and measuring its rate of expansion at that time. This requires gathering a considerable amount of data. More specifically, DEX is determining the position of 2.5 million galaxies and measuring the speed at which they are moving away from us. The DEX began in 2017 and is expected to be completed by December 2023. E
We were able to view the HET; however, only from behind a clear plastic enclosure. Fortunately, our tour guide provided an extensive explanation of how it worked and what it was doing. We saw a display of a single hexagonal mirror and support mechanism (pictured below). Of course, the earth is rotating as HET views galaxies and collects data, so the mirrors of the telescope must be adjusted frequently by computers to provide the perfect reflecting surface.
The “Sky Party” didn’t begin until after sunset. We drove back to our hotel, took naps, and enjoyed an excellent steak dinner at the restaurant next door. We returned to Mount Locke and were treated to a spectacular sunset. Rain had been forecast for the evening, but the weather cooperated with a clear sky.
Guides directed us to the outside amphitheater behind the Visitor Center once it was dark. An observatory scientist conducted an interesting lecture/discussion/Q&A/stoty-yelling about the night sky and described the five telescope viewings planned for the evening. She spent worthwhile time re-teaching us the basics, and more, of star-gazing, which many of us had learned as kids. Where’s the North Star, what planets are visible, what are the names of the visible constellations, etc? With her talk, she was also allowing for the phenomenon of “dark adaptations,” to occur. This is the process by which it takes our eyes about 40 minutes to adjust to seeing in darkness. Finally, the length of her talking was meant to let the audience of about 80 people depart the amphitheater at staggered times so as not to cause long waits in lines at each viewing. Didn’t work at all, but the lines moved quickly enough.
Local astronomers brought their personal telescopes for three of the viewings, and on-site telescopes were used for the other two. We viewed the “moon interrupter” first. The interrupter is the edge between the bright and dark sides of the moon. It was the closest I’d ever seen the moon, and by looking at the interrupter, the craters and surface features were strikingly clear with distinctive shadows. An “oh wow” moment for sure!
Our remaining four viewings were all what astronomers call Messier Objects: a spiral galaxy, a sombrero galaxy, an open (small) star cluster, and a large globular star cluster. Charles Messier was a French astronomer in the 18th century. In his hunt for comets, he also discovered 103 fixed diffuse objects, which he cataloged meticulously. Each Messier Object was designated by an “M” and a number and ultimately were published on a list in 1781. While we were told the Messier designation for each viewing, I can only remember one: M1 the spiral Adromeda Galaxy. Andromeda is the closest galaxy to the Milky Way at 2.5 million light years. The sombrero galaxy was also a spiral galaxy viewed from its edge. Out of the center was a bulge of stars, which is what made it look like a sombrero.
Next, we viewed the two star clusters. What made them interesting was the difference in numbers of stars they contained and their distance from us. The “open cluster” contained approximately 1,000 stars and was 50,000 light years away. In contrast, the globular cluster contained an estimated 1,000,000 stars and was 50 million light years from us. Frankly, we couldn’t wrap our heads around the magnitude of these numbers and the related vastness of the universe. While waiting in line for one viewing, the crowd began murmuring and pointing to the low northern sky. We looked up just in time to see a line of moving white lights, which it turns out was sunlight reflecting off of 10 (out of the 4,000 in low-earth orbit) SpaceX Starlink Satellites. That was a bonus viewing! Too bad there was no way to take pictures.
We didn’t get back to our hotel until after midnight. Was smart that we napped. For me, this side trip was the highlight of our two weeks in southwest Texas. But our connection with “space” wasn’t over. Several afternoon’s later we were chilling when there was a knock on Arthur’s door. We were greeted by unknown neighbors who broke the ice by handing us beers and asking us about our AirSkirts. Patrick and Jill McClure sat and talked with us a while. He is an amateur photographer, who loves taking pictures of night skies. They had just taken advantage of several “dark sky” nights in nearby Big Bend Ranch State Park where he captured some great shots. He shared these two with us.
We aren’t drinking much alcohol these days, but the McClure-gifted beers sure hit the spot on that burning hot afternoon. These pictures capture how much we’re still loving this adventure.
