The 1-meter Swedish solar telescope

We describe the 1-meter Swedish solar telescope which replaces the former 50-cm solar telescope (SVST) in La Palma. The un-obscured optics consists of a singlet lens used as vacuum window and two secondary optical systems. The first of these enables narrow-band imaging and polarimetry with a minimum of optical surfaces. The second optical system uses a field mirror to re-image the pupil on a 25 cm corrector which provides a perfectly achromatic image, corrected also for atmospheric dispersion. The adaptive optics system is integrated with the design of the telescope but is sufficiently flexible to allow future upgrades. It consists of a low-order bimorph modal mirror with 37 electrodes, allowing near-diffraction-limited imaging a reasonable fraction of the observing time on La Palma. The new telescope became operational at the end of May 2002 and has already proven to be the most highly resolving solar telescope ever built. In this paper, we describe its mechanical and optical design, the polishing and testing of the optics and the instrumentation in use or planned for this telescope.