Quality Control and Instrument Trending for MIDI: First Quality Control and Data Flow Operations Results I. Percheron a , P. Ballester a , C. Sabet b , M. Wittkowski a , S. Morel a , A. Richichi a a European Southern Observatory (ESO), Karl-Schwarzschildstr. 2, D-85748 Garching bei München b Tekom GmbH, Gautinger Str. 29, D-82152 Krailing ABSTRACT The ESO Data Flow Operations group (also called Quality Control group) is dedicated to look into the performance of the different VLT instruments, to verify the quality of the calibration and scientific data, to control and monitor them on different time scales. At ESO headquarters in Garching, Germany, one QC scientist is dedicated to these tasks for the VLTI instruments: VINCI, MIDI, AMBER, and (eventually) PRIMA. In this paper, we focus on MIDI. In this presentation, we define the tasks of the Quality Control scientist and describe the lessons learned on quality control and instrument trending with the commissioning instrument VINCI. We then illustrate the different aspects of the MIDI Data Flow Operations supported by the QC scientist such as data management issues (data volume, distribution to the community), processing of the data, and data quality control. 1. THE VLTI INSTRUMENTS The VLT Interferometer (VLTI) has been operating since the first fringes obtained with the 2μm VLTI commissioning instrument VINCI. The next instrument operating in the VLTI environment, MIDI, obtained the first fringes using 2 Unit Telescopes (UTs) end of 2002. MIDI (the MID-infrared Instrument for the VLT Interferometer) is a long-baseline direct interferometer in the mid-infrared (N band: 8 to 12 microns) that records spectrally-dispersed fringes. MIDI is the first instrument to allow observations with large apertures and hectometric baselines at such wavelengths. More information on the MIDI instrument and the scientific objectives are given in several papers in these proceedings [4, 5]. MIDI observations will be done in the future with the UTs as well as with the Auxiliary Telescopes (ATs). Several instruments are following MIDI: AMBER (the near infrared/red VLTI focal instrument), PRIMA (the instrument for Phase- Referenced Imaging and Microarcsecond Astrometry). 2. QUALITY CONTROL AND DATA FLOW OPERATIONS 2.1. What are the tasks of the Quality Control scientist? Most of the tasks are common to each VLT/VLTI Quality Control (QC) scientist [7]. The main activities are to verify the quality of the data, to monitor the performances of the instrument and to distribute scientific data to the Service Mode users. The main steps of the Data Flow Operations (DFO) will be described in the following section 2.2. During the commissioning of the different instrument modes, the QC scientist also verifies the integrity of the FITS headers keywords associated to each standard observation mode (template). This step is critical to assure accurate automatic data association and data processing. For each VLT/VLTI instrument, ESO follows a calibration plan both for the calibration of the science data and to monitor the health of the instrument. In the case of MIDI, there are two types of calibration data: the technical calibrations for determination of the read out noise, characterization of the detector linearity, stability of the reference pixels, transmission of the dispersive optical elements, wavelength calibration and determination of the throughput of the instrument; and the astronomical calibration measurements to remove the atmospheric and the instrumental effects signature imposed on the science data. Send correspondence to ipercher@eso.org