THE SOLAR-STELLAR SPECTROGRAPH - PROJECT DESCRIPTION, DATA CALIBRATION, AND INITIAL RESULTS

The Solar-Stellar Spectrograph (SSS) is a project initiated in the 198 0s by scientists from the High Altitude Observatory, Lowell Observator y, the Pennsylvania State University, and the Sacramento Peak Observat ory. The instrument is comprised of two spectrographs: one is an echel le covering the wavelength range lambdalambda5000-9200, while the seco nd is a Littrow spectrograph covering the Ca II H and K region around lambda3950. This project is designed to address a broad range of outst anding questions regarding the nature of stellar activity cycles. The unique capability of the spectrograph is its ability to record both so lar and stellar spectra, allowing more accurate placement of the Sun i n the stellar context than has been feasible previously. In this repor t we discuss the motivation for this project, the instrumental charact eristics, the observing programs, the methods being used to reduce, ca librate, and analyze the data, and the connection of our database to e xtant databases. A central part of the discussion is the connection of the Sun with the stars both in terms of existing solar and stellar ac tivity indices as well as physical flux. This work resolves a long-sta nding discrepancy in this area and establishes a protocol for relating the large set of observations from the Mount Wilson Ca II H and K pro ject to physical flux, in preparation for future comparison to our obs ervations and results from theory.