Weather Report for April 12, 2013

Despite the rather benign appearance of the weather satellite picture, observations had to be made through clouds all night. Only the brightest targets could be observed. Therefore, almost the entire night was spent observing Mrk421 for polarization, since it is reported to be in an unprecedented bright state at both TeV and X-ray energies. The seeing varied between 1.4 and 2 arcsec.