Perched six floors above Dallas’ historic Dealey Plaza area, where President John Fitzgerald Kennedy was shot, The Sixth Floor Museum at Dealey Plaza is safekeeping for a variety of documentary materials surrounding the November 22, 1963 assassination. More than half a million people visit The Sixth Floor each year to learn more about the fateful day through original photographs, newspaper clippings, letters, films, and FBI reports.
While the museum’s first priority is to make these artifacts accessible to the public, it also must ensure that each object is protected and preserved from harmful environmental conditions. These include fluctuating temperature and relative humidity (RH) levels, and excessive light intensity.
“Our collection includes artifacts composed of a wide range of materials,” explains Lacie Ballinger, Collections Coordinator at The Sixth Floor Museum. “We have a ten-foot by ten-foot FBI scale model of Dealey Plaza on loan from the National Archives, which was used by the Warren Commission to analyze the trajectory of bullets. The model has glass walls, a Plexiglas top, and construction paper was used to simulate the surroundings, so it’s extremely light sensitive. We also have wooden objects such as Caroline Kennedy’s footstool, and textiles such as the flag that flew at half-mast over the Capitol after the assassination. With so many different types of materials, it can be a challenge to maintain the proper environment for our collections.”
As part of its indoor environment control strategy, The Sixth Floor Museum relies on HOBO® data loggers from Onset for continuous monitoring of temperature, RH, and light intensity. HOBO loggers are battery-powered, stand-alone devices that are equipped with a built-in microprocessor, memory for data storage, precision temperature, RH, and light intensity sensors, and a user-replaceable battery. The loggers interface with a computer and utilize a software program that activates the logger and enables the user to view and analyze the collected data.
At The Sixth Floor, HOBO data loggers are magnetically attached to various 10-foot-high metal ceiling beams throughout the facility. The beams, explains Ballinger, help maintain the warehouse look of the former Texas Schoolbook Depository from which the museum was converted in 1989. Each logger is set to record temperature, RH, and light every 12 minutes. “In general, we try to keep the temperature between 67 and 73 degrees Fahrenheit in most areas, humidity 50 to 55 percent, and light intensity between 5 to 0 footcandles, depending on the specific objects in the area that’s being measured.”
After two weeks worth of data has been collected, Ballinger retrieves the data using a data shuttle supplied by Onset. This pocket-sized device can offload and store the data from each logger, which Ballinger then takes back to a computer for data graphing and analysis using Onset’s BoxCar® Pro software. The software instantly translates the collected data into easy-to-read graphs that clearly show the temperature, humidity, and light readings for the two-week period. Ballinger is able to create custom charts for documentation purposes, and print them out for use at meetings. Since the data loggers were purchased in 2001, they have been functioning 24/7 without any problems. By continuously monitoring The Sixth Floor’s environmental conditions, the loggers are helping preserve artifacts connected to one of the most important and controversial pieces of American history.
Ballinger concludes, “The most important characteristic that we like about the HOBOs is that they pinpoint when events occur, like when an air handler turns off, and from that we can judge cause and effect. This is much more difficult to do with chart recorders. We also like the fact that the loggers can be hidden very easily in exhibit areas and visitors don’t notice them.” For more information about data loggers, please contact Onset Computer Corporation at 1-800-LOGGERS, or visit www.onsetcomp.com.