1. A method to determine sample points for entering magnetic resonance (MR) data into k-space with a random undersampling scheme comprising: in a processor, automatically determining a set of sample points for entering reduced MR data, to be acquired by multiple reception coils of a magnetic resonance data acquisition unit, into an electronic memory representing k-space, according to a random undersampling scheme; in said processor, automatically determining calculated reconstructed MR data suitable to be reconstructed from the reduced MR data, and also automatically calculating an indicator of a signal noise in said calculated reconstructed MR data; in said processor, determining an additional sample point in k-space that is not included in said set of sample points; in said processor, calculating a change of said indicator that results by addition of said additional sample point to said set of sample points; in said processor, selectively adding or not adding said additional sample point to said set of sample points dependent on the calculated change, to obtain a further set of sample points; operating said MR data acquisition unit to acquire reduced MR data for said further set of sample points with said multiple reception coils; and in said processor, reconstructing a set of reconstructed MR data from the reduced MR data for said further set of sample points, and making the reconstructed MR data available as a data file at an output of said processor.