Getting ready for high accuracy measurements: The VLTI Calibrators Program

摘要

The VLTI Calibrators Program is a common project between ESO and NEVEC. The main goal is to establish a network of measurements of calibrator objects with an accuracy high enough to fully exploit the different VLTI instruments. We started this project in 2001 by defining a list of objects to be used during the observations with the commissioning instrument VINCI. During the first year of observation (18th March 2001-18th March 2002), a total of 5060 observations have been recorded on 156 astronomical objects. More than 60% of the observations have been done on 63 calibrator objects. These calibrator data are currently analyzed to refine the measurements of the adopted diameters. After a brief description of the instrument and of the data reduction process, we describe the criteria used to establish a list of calibrators suitable for the commissioning instrument VINCI with baselines of up to 200m. We define a strategy to observe and analyze the data for the commissioning of the VLTI and of several baselines. We emphasize the difficulties of instrumental calibration to an accuracy of a few 0.1% and the necessity of a long term effort.