Abstract: We spectroscopically re-observed the gravitational lens system SDSS J1339+1310 using OSIRIS on the GTC. We also monitored the r-band variability of the two quasar images (A and B) with the LT over 143 epochs in the period 2009-2016. These new data in both the wavelength and time domains have confirmed that the system is an unusual microlensing factory. The C iv emission line is remarkably microlensed, since the microlensing magnification of B relative to that for A, ?BA, reaches a value of 1.4 (?0.4 mag) for its core. Moreover, the B image shows a red wing enhancement of C iv flux (relative to A), and ?BA = 2 (0.75 mag) for the C iv broad-line emission. Regarding the nuclear continuum, we find a chromatic behaviour of ?BA, which roughly varies from ?5 (1.75 mag) at 7000 Å to ?6 (1.95 mag) at 4000 Å. We also detect significant microlensing variability in the r band, and this includes a number of microlensing events on timescales of 50-100 d. Fortunately, the presence of an intrinsic 0.7 mag dip in the light curves of A and B, permitted us to measure the time delay between both quasar images. This delay is ?tAB = 47+5 -6d (1? confidence interval; A is leading), in good agreement with predictions of lens models.

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