Balloon-borne telescope for high-resolution solar imaging and polarimetry

In January 2000, an 80-cm F/1.5 Ritchey-Chretien solar telescope flew for 17 days suspended from a balloon in the stratosphere above Antarctica. The goal was to acquire long time series of high spatial resolution images and vector- magnetograms of the solar photosphere and chromosphere. Such observations will help to advance our basic scientific understanding of solar activity, in particular flares. Flying well above the turbulent layers of the Earth's atmosphere, the telescope should be able to operate close to its diffraction limited resolution of 0.2 arcsec, providing high resolution observations of small scale solar features. To achieve this goal we developed a platform for the optical telescope that is stable to nearly 10 arcsec. We also developed an image motion compensation system that stabilizes the solar image on the CCD focal plane to about 1 arcsec.