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We present the strategies adopted in the relative and absolute calibration of two different data sets: U,B,V,I-band images collected with the Wide Field Imager (WFI) mosaic camera mounted on the 2.2m ESO/MPI Telescope and u,v,b,y Stroemgren images collected with the 1.54m Danish Telescope (ESO, La Silla). In the case of the WFI camera we adopted two methods for the calibration, one for images collected before 2002, with the ESO filters U/38_ESO841 and B/99_ESO842, and a different one for data secured after 2002, with the filters U/50_ESO877 and B/123_ESO878. The positional and color effects turned out to be stronger for images collected with the old filters. The eight WFI chips of these images were corrected one by one, while in the case of images secured with the new filters, we corrected the entire mosaic in a single step. In the case of the Danish data set, we compared point-spread function (PSF) and aperture photometry for each frame, finding a trend in both the X and Y directions of the chip. The corrections resulted in a set of first and second order polynomials to be applied to the instrumental magnitudes of each individual frame as a function of the star position.
We report on the implemented design of a two-colour instrument based on electron multiplying CCD (EMCCD) detectors. This instrument is currently installed at the Danish 1.54m telescope at ESOs La Silla Observatory in Chile, and will be available at t
Absolute calibration of the Pierre Auger Observatory fluorescence detectors uses a 375 nm light source at the telescope aperture. This end-to-end technique accounts for the combined effects of all detector components in a single measurement. The rela
Aims: To investigate a possible dependence between age and metallicity in the Magellanic Clouds (MCs) from a study of small open star clusters, using Str{o}mgren photometry. Our goal is to trace evidence of an age metallicity relation (AMR) and corre
We describe a process for cross-calibrating the effective areas of X-ray telescopes that observe common targets. The targets are not assumed to be standard candles in the classic sense, in that we assume that the source fluxes have well-defined, but
Learning optimal policies from historical data enables the gains from personalization to be realized in a wide variety of applications. The growing policy learning literature focuses on a setting where the treatment assignment policy does not adapt t