TESELA: a new Virtual Observatory tool to determine blank fields for   astronomical observations
  The observation of blank fields, regions of the sky devoid of stars down to a given threshold magnitude, constitutes one of the typical important calibration procedures required for the proper reduction of astronomical data obtained in imaging mode. This work describes a method, based on the use of the Delaunay triangulation on the surface of a sphere, that allows the easy generation of blank fields catalogues. In addition to that, a new tool named TESELA, accessible through the WEB, has been created to facilitate the user to retrieve, and visualise using the VO-tool Aladin, the blank fields available near a given position in the sky. 
N. Cardiel, F.M. Jim\'enez-Esteban, J.M. Alacid, E. Solano and M.   Aberasturi
astro-ph.IM