First Results from SOLIS


SOLIS (Synoptic Optical Long-term Investigations of the Sun) is a project to replace antiquated synoptic observing equipment at the National Solar Observatory. SOLIS includes a suite of three instruments on an equatorial mount originally installed at a site in Tucson and will be moved to Kitt Peak before the end of 2003. The major SOLIS instrument is a vector spectromagnetograph that maps magnetic fields across the full solar disk using a slit spectrograph and one arc sec pixels. Daily observations include several line-of-sight component magnetograms in the photosphere and chromosphere and, for the first time, full-disk vector magnetograms. At a medium scan speed ( ensuremath∼10 minutes for the full disk) noise is less than 1 Mx/cm$^2$. This low noise, combined with negligible instrumental polarization and well resolved spectral line profiles, yields moderate resolution magnetograms of unprecedented quality. Sample observations show magnetic flux nearly everywhere in the photosphere from the disk center to the solar limb. The flux is organized in large scale patterns that heretofore had been visible only in strong flux elements or after substantial spatial smearing. Good results have been obtained from the other SOLIS instruments: a full-disk filter imager at several narrow wavelengths and a grating spectrograph that provides high-accuracy line spectra of integrated sunlight. SOLIS data are freely available via the Internet and users may submit observing time requests for special observations. The National Solar Observatory is operated by AURA, Inc. under a cooperative agreement with the National Science Foundation. Additional support for the development of SOLIS from NASA and ONR is gratefully acknowledged.

AGU Fall Meeting Abstracts