The Research Station for Astrophysics of the Royal Swedish Academy of Sciences runs a 0.5-m solar telescope on the Canary Island of La Palma. The research in solar physics takes advantage of the superb observing site to study small-scale solar phenomena such as granulation, sunspot structure, and small magnetic elements. This is done with techniques for imaging, spectroscopy, and polarimetry that are being developed in Stockholm and on La Palma to allow sub-arcsecond resolution.
The telescope is used by many guest observers for solar (and planetary) studies. Many of their observing programs are collaborations with the scientific staff based in Stockholm. Essentially all the observational programs are designed to take advantage of the high spatial resolution obtainable. An example of this is the studies of the small photospheric bright points that are especially bright when imaged in the wavelength of the G band and are tracers of enhanced magnetic fields. These bright points are barely resolved at the diffraction-limit of the telescope, and the phase-diversity technique for wavefront sensing and image restoration has been frequently employed in their study.
During 1997 and 1998 several observational runs were made in coordination with observations by the SOHO and TRACE spacecraft. The TRACE programs led to the discovery of a new kind of coronal emission from active regions called "moss", which does not have a simple correspondence to the photospheric magnetic field.
Other scientific projects of the Stockholm staff include observational and
theoretical studies of photospheric line formation processes aimed at
improving abundance analysis work, observations of H- 
wings for
testing photospheric convection models, studying the structure and dynamics
of sunspot penumbræ, and magnetographic studies of weak solar magnetic
fields.
On the instrumentation side, the correlation tracker that allows precise tracking and image stabilization has been made more efficient and reliable, more cameras have been added and the computer interfaces of the cameras have been improved; some of this development was performed in collaboration with researchers at Compaq's (formerly Digital Equipments') systems research center. The properties of the magnetographic setup have been investigated in order to improve it. The development of an adaptive optics system using new methods for wavefront sensing has started. Such a system will be essential for the new solar telescope which was designed during the period. Funding of the new telescope, which will be of twice as large aperture as the current one, has been secured and construction work has started. The new telescope is planned to replace the current one in early 2001.