Phase screen on long baselines of LOFAR

Image may be NSFW.
Clik here to view.© Neal Jackson/Long Baseline Working Group

Each frame of this movie shows the derived phase correction (left) of a number of different sources in the Long-Baseline Working Group test field, on the baseline from Exloo (phased-up core stations) to Effelsberg. The movie is based on an 8-hour observation, and phase corrections and imaging have been done by hand (although we are working to automate the process!) Phases are referenced to 1327+5504, the bright source towards the right-hand side of the picture, and are colour-coded on a colour loop (cyan=0). Note the slow variations close to the reference source, and the faster and more high-amplitude variations further from the reference source. The right hand panel shows the ionospheric delay relative to 1327+5504, with a colour scheme ranging from pink (-100ns) to white to yellow (100ns). Only one source is bright enough to derive good delays.