Sigma significance map from LEGRI observation of Crab. Positive B-spline image on a 21 × 21 net with 2 degree pitch. Exposures with count rates outside 3.5-6.0 cnts/sec excluded.
First image made of Crab using data from the LEGRI coded mask telescope with the false assumption that the background rate in each detector does not vary with time and resulting in the significant image artifacts seen which will be removed after a satisfactory background model has been decided.