strange thing on this picture
Can somebody tell me what that thing is we see on the lower left?
Many thanks in advance
It's a (fairly) bright star in our own galaxy. It's so bright that it overloads the CCD pixels at and near its center, producing the strange patterns. The line is a diffraction spike, produced by light bouncing off one of the four vanes which hold the secondary mirror in the telescope in place (there are four of these spikes, you can just see one of the others; they're like the points of a compass).