Cell phone service in our area is spotty to non-existent.
Depending on your cell carrier, service is generally available in the local towns of Fort Davis, Alpine, and Marfa, but there are significant dead zones in between.
The publicly accessible areas at the Observatory do not have cellular phone service, and the Visitors Center does not provide public WiFi service in our facilities. During evening programs, we prohibit the use of any electronic devices (smart phones, tablet computers, iPods, etc) that have a light-emitting screen, at least in our telescope park and amphitheater areas. Your best views of the night sky are possible only when your eyes are fully dark-adapted, and even at minimum brightness setting, these devices are too bright to maintain dark adaptation.