Location: Hvar, Croatia
Owner: Faculty of Geodesy - University of Zagreb
The double solar telescope at Hvar Observatory (HO) was installed in 1972 and is operated by the Faculty of Geodesy, University of Zagreb, Croatia. One of the aims of HO is to complement Kanzelhöhe full-disc images by HO active region high-resolution images.
The main objective of the Hvar photospheric telescope is achromatic doublet with diameter of 217 mm and the focal length of 2450 mm. The solar continuum filter is designed to enhance the visibility of solar granulation and sunspot details by transmitting a specific spectral region around 540 nm, free of emission and absorption lines, thus boosting the contrast and reducing the effects of atmospheric turbulence. The field of view of the corresponding system is about 11.28 arcmin, yielding the resolution of 0.33 arcsec/pix with 4MPix CCD camera.
The optical system of the chromospheric telescope consists of an energy reduction filter, iris diaphragm, main objective, auxiliary lens, H-alpha filter and CCD camera. The main objective is achromatic doublet with a diameter of 130 mm and focal length of 1950 mm. The energy reduction filter blocks most of the sunlight, thus decreasing the heating and turbulence inside the telescope. The Baader research grade filter is used as H-alpha filter with the narrow 0.2 Å passband. The field of view with corresponding system is about 7.15 arcmin wich gives 0.21 arcsec/pix with 4MPix CCD camera.