ON THE DIGITISATION OF ODESSA COLLECTION OF ASTRONOMICAL NEGATIVES. EXAMINATION OF THE EPSON PERFECTION V700 PHOTO SCANNER

Abstract

This study was aimed to estimate the precision of the selected plate processing method and test the accuracy of the Epson Perfection V700 Photo scanner used to digitize astroplates from the Odessa Astronomical Observatory’s collection. The processing of astroplates was performed using specific software developed in the LINUX/MIDAS/ROMAFOT environment. In order to estimate the repeatability of the scanner’s astrometric and photometric errors, six consecutive scans of one and the same plate (No 17,000 — the Pleiades star cluster) were processed in two scanning modes with spatial resolutions of 1,200 and 2,400 dpi. The plate was exposed for 30 minutes with the fourth tube of the Seven Wide Angle (SWA) astrograph. The scan size was 18 x 24 cm (13 x 18 degrees). The following estimates of the scanner’s accuracy were obtained for the stars brighter than B < 13 m in the two scanning modes:1) σxy = ± 0.023 px, σm = ± 0.013m; 2) σxy = ± 0.082 px, σm = ± 0.042m for the Cartesian coordinates and instrumental magnitude, respectively.