By analyzing data from astronomical surveys, Japanese astronomers have detected a new, extremely variable quasi-stellar object (QSO), or quasar. The newly found object, designated SDSS J125809.31+351943.0, brightened in optical band for 4.0 mag over three decades, which means that it was one of the largest quasar brightening events so far recorded. The finding is reported in a paper published November 3 on arXiv.org.