Eulaers, E.Tewes, M.Magain, P.Courbin, F.Asfandiyarov, I.Ehgamberdiev, ShKumar, S. RathnaStalin, C. S.Prabhu, T. P.Meylan, G.Van Winckel, H.2013-10-012013-10-012013-10-01201310.1051/0004-6361/201321140https://infoscience.epfl.ch/handle/20.500.14299/95412WOS:000319858700121Aims. Within the framework of the COSMOGRAIL collaboration we present 7- and 8.5-year-long light curves and time-delay estimates for two gravitationally lensed quasars: SDSS J1206+4332 and HS 2209+1914. Methods. We monitored these doubly lensed quasars in the R-band using four telescopes: the Mercator, Maidanak, Himalayan Chandra, and Euler telescopes, together spanning a period of 7 to 8.5 observing seasons from mid-2004 to mid-2011. The photometry of the quasar images was obtained through simultaneous deconvolution of these data. The time delays were determined from these resulting light curves using four very different techniques: a dispersion method, a spline fit, a regression difference technique, and a numerical model fit. This minimizes the bias that might be introduced by the use of a single method. Results. The time delay for SDSS J1206+4332 is Delta t(AB) = 111.3 +/- 3 days with A leading B, confirming a previously published result within the error bars. For HS 2209+1914 we present a new time delay of Delta t(BA) = 20.0 +/- 5 days with B leading A. Conclusions. The combination of data from up to four telescopes have led to well-sampled and nearly 9-season-long light curves, which were necessary to obtain these results, especially for the compact doubly lensed quasar HS 2209+1914.gravitational lensing: strongcosmological parametersquasars: individual: SDSS J1206+4332quasars: individual: HS 2209+1914text::journal::journal article::research article