Calibrating Astronomical Instruments to Improve the Science Gained from the Large Synoptic Survey Telescope

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The future Large Synoptic Survey Telescope (LSST) of the United States will revolutionize astronomy by obtaining images of objects observed repeatedly over long periods of time. These observations will be extremely accurate. In order to get the best science from these observations, two types of additional, supporting observations will also be used: observations that have been made using different telescopes and instruments in the past, and observations that will be made with other telescopes and instruments in the future. For all of these supporting observations to be useful, they must be as accurate as the observations that will be taken using the LSST. For this project, the astronomers will calibrate the telescopes, instruments, and sky conditions of the observatories where the other observations are or will be made. This project serves the national interest, as it ensures that the data acquired with the new telescope will contribute the best scientific results possible, promoting the progress of observational astronomy. The astronomers are from Texas A & M University, which draws most of its students from a heavily Hispanic population. The investigators intend to employ two graduate students and 8 - 10 undergraduate students.The Large Synoptic Survey Telescope (LSST) project will produce an enormous amount of photometric data that will revolutionize the field of astronomy. One of the LSST goals is to provide an unprecedented level of photometric accuracy: 0.5%. Existing and on-going data from other telescopes will be used for comparison and follow-up observations with the new LSST observations. These observations, however, will need to be very well calibrated. The investigators will use existing equipment to provide accurate spectrophotometric calibration of imaging systems at observatories around the world. The calibration will include in-situ measurements of the telescopes, optics, filters, and detectors, providing detailed knowledge of the transmission profiles of the instruments. The atmospheric transmission above the observatory sites will also be measured. Together, these measurements will help to enable exceptionally accurate photometric calibration of these systems. Based on similar measurements of the DECam instrument and the Cerro Tololo Inter-American Observatory location, the investigators estimate that the proposed work should allow for accuracy of ~0.2% across large surveys and all spectral bands.