Cerberus: A three-headed instrument for the OARPAF telescope

We present the preliminary design of Cerberus, a new scientific instrument for the alt-az, 80cm OARPAF telescope in the Ligurian mountains above Genoa, Italy. Cerberus will provide three focal stations at the Nasmyth focus, allowing: imaging and photometry with standard Johnson-Cousins UBVRI+H alpha+Free filters, an on-axis guiding camera, and a tip-tilt lens for image stabilization up to 10Hz; long slit spectroscopy at R similar to 5900 thanks to a LHIRES III spectrograph provided with a 12001/mm grism; echelle spectroscopy at R similar to 9300 using a FLECHAS spectrograph with optical fiber.