MRI: Development of a Solar Photometric Instrument: Cartesian Full Disk Telescope-3 (SOPHI-CFDT3)

The main thrust of this 3-year MRI project is to develop a second-generation of photometry program at the San Fernando Observatory (SFO) that is built upon the strong foundation laid by the original program. This would yield photometric studies of the Sun, which is a powerful tool for modeling and understanding solar variability. The current solar cycle 24 demonstrates that solar variability is still unpredictable, and therefore requires continued measurement. While absolute solar radiative flux is measured from space, solar images from ground-based telescopes are used to decipher information about the photospheric and chromospheric sources of variability. The SFO and California State University at Northridge (CSUN) are well suited to continue to carry out long term photometric observations, while keeping costs low and employing undergraduate and graduate students, as well interested faculty. The resulting data product will be a uniform photometric record of daily solar images in multiple wavelengths, eventually at least 50 years long, which will yield information needed to study active region contributions to solar irradiance across two or more Hale magnetic cycles. The models to be developed with the new CFDT3 data will be used to: (1) provide support for space-based irradiance monitors; (2) characterize past and future variations in the amount of solar power reaching Earth; and, (3) gain deeper understanding of the physical sources of the Sun?s irradiance changes. The SFO/CFDT photometry program records full-disk solar images at multiple wavelengths on all sunny days (about 65% of the year), and maintains an archive of metadata describing solar variability.

The broader impact of the SFO?s photometry program is four-fold: (1) maintain a fundamental scientific data set; (2) support space-based solar irradiance monitors; (3) generate secondary data of interest to the larger scientific community; and, (4) fulfill an educational mission. Using the new data from CFDT3, the project team will reconstruct changes in the Sun?s total and spectral radiative output. These reconstructions are a valuable tool for the solar irradiance research community: not only do they provide scientific information, but they also allow the identification of discontinuities in the space-based irradiance record that can help bridge gaps between spacecraft missions. The analyses of solar variability are applicable to the study of other Sun-like stars. A major impact is educating undergraduate and graduate students in observational solar physics. California State University at Northridge is designated as an Hispanic Serving Institution and Asian American Native American Pacific Islander Serving Institution. Its pool of students reflects the ethnic diversity of its geographic area. CFDT3 is a hands-on instrument that will entice and encourage students to explore and consider Science, Technology, Engineering, and Mathematics (STEM) careers. Its accessibility allows for its integration into CSUN?s Physics and Astronomy curriculum at both graduate and undergraduate levels. Public outreach efforts through CSUN planetarium presentations expose the ethnically diverse population of the San Fernando Valley to the possibilities of scientific research.