{"id":163,"date":"2016-11-12T16:49:42","date_gmt":"2016-11-12T15:49:42","guid":{"rendered":"https:\/\/escience.aip.de\/robo\/?page_id=163"},"modified":"2017-01-18T15:43:39","modified_gmt":"2017-01-18T14:43:39","slug":"calibration-unit","status":"publish","type":"page","link":"https:\/\/pepsi.aip.de\/?page_id=163","title":{"rendered":"Calibration unit"},"content":{"rendered":"

Two comparable standard calibration units exist and can be internally exchanged if needed. One unit serves all standard telescope foci while the other serves just the Fabry-P\u00e9rot unit on the optical bench of the spectrograph. Each unit contains three halogen lamps (two hot spares) and two Th-Ar lamps (one hot spare). We employ flat-field halogen lamps with four fibre exits and Th-Ar lamps with single fibre exits. The halogen sources are tunable 100 W lamps from LOT-Oriel. The Th-Ar lamps are from Photron and Juniper.<\/span><\/p>\n

Beside the standard wavelength calibration, PEPSI radial velocities can be obtained relative to a Fabry-P\u00e9rot etalon. The etalon fringes are imaged simultaneously with the target spectrum. On average more than hundred fringes are available per echelle order.<\/p>\n