As the Sun is low in the western sky Dr. Angelle Tanner and her student, Randy Niffenegger, quickly finish their dinner. They then scour the cafeteria to fill a brown paper bag with enough snacks and drinks to last the entire night. Just to be sure, Randy wraps up an extra piece of the impressively good cherry chocolate cake.
For the third night in a row, they make their way up the hill to the WIYN telescope. This facility, located at an altitude of 6900 feet at the Kitt Peak National Observatory, houses a 3.5-meter diameter telescope. Tonight, the two weary astronomers are continuing their efforts to study how the intrinsic variability of stars might impact our ability to find new extrasolar planets orbiting around them.
After entering the small building which houses the telescope, they notice Karen, the telescope operator, coming into the room from the telescope dome. She came up to the telescope a few minutes earlier to prepare it for the night’s observing. This involves booting up the computers, opening the dome shutter and levelers and filling the telescope’s infrared camera with liquid nitrogen. She tells the astronomers that the calibration data has been finished and they can go to a bright calibration star when they are ready.
The rest of the night involves a repetition of similar steps: move to a new location in the sky, center the main science star and nearby reference stars on the desired part of camera and collect a few hours of continuous images which each have exposure times of 30 seconds. If they keep the camera shutter open any longer, the bright science star will be saturated, and the data will not be useable. In the end, these images will result in a series of data points representing the brightness of the star over the time span of a few hours. The reference stars are used to help remove variations caused by the turbulence in the Earth’s atmosphere.
As the night progresses, the observers are getting weary. Randy starts another series of exposures of a star which will be observed with the TESS (Transiting Exoplanet Survey Satellite) telescope. Collecting reconnaissance data on its intended targets now will help astronomers decide whether these stars have bona fide exoplanets orbiting around them. Dr. Tanner stares at her list of stars and tries to decide which target should be next given the amount of time left before sunrise and the atmospheric conditions.
After a few yawns, some blinking and a refreshed cup of coffee she decides that they’ll finish off the night getting more data on Tabby’s star, an enigmatic object whose random reductions in brightness have been attributed to anything from extraterrestrials to star-diving comets. Randy notices that the latest set of observing commands has finished and Dr. Tanner asks Karen to move to Tabby’s star.
The telescope observations end when the Sun comes up and begins to flood the infrared camera with its own light. Karen notices the guide camera has lost tract of Tabby’s star so that’s all the data they will get that night. Neither the observers or Karen are done with their work, however. Randy looks up all the different integration times they used over the night and begins to collect dark current frames. Karen goes into the telescope dome to close the shutter and the mirror cover and shut down some of the electronics that don’t need to be on during the day. Dr. Tanner makes a quick list of the stars with the highest priority for observing on their last night.
As Dr. Tanner and Randy walk back down the mountain to their dorm rooms the Sun is a few degrees above the horizon and the birds are chirping. Randy stops to get a picture of the long shadows created by the forest of telescopes. Dr. Tanner continues toward a bed trying not to stumble down the steep hill. A small crowd of tourists can be seen listening to a tour guide outside the gift shop.
“Just one more night on this beautiful mountain”, Dr. Tanner thinks to herself as she happily gets under a warm blanket only to start the entire process over again in eight hours.