All Figures

$\begin{figure} \par\includegraphics[width=13cm,clip]{1887Fig1.eps}\par\end{figure}$ Figure 1: For a given observing date (Oct. 29, V), we show aligned CCD frames Ref ( top left), I ( top right) and Sub ( bottom left). The image Sub is the result of the subtraction of the frame I from the reference frame Ref convolved with an optimal kernel. In these frames, north is up and east is to the right. Field of view is approximately $3'\times 3'$ . The top left inset illustrates the flux variations of the four lensed QSO components between the frames I and Ref.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=8.2cm,clip]{1887Simu.eps} \end{figure}$ Figure 2: An example of CCD frame simulated for the statistical determination of the photometric error bars: the frame corresponds to the same observing date as Fig. 1 (Oct. 29, V).
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[angle=-90,width=13cm,clip]{1887Vban.eps} \end{figure}$ Figure 3: Light curves of the lensed components A, B, C and D of Q2237+0305 in the V band. Magnitude is plotted with error bars as a function of time (heliocentric Julian Days -2 450 000).
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[angle=-90,width=13cm,clip]{1887Rban.eps} \end{figure}$ Figure 4: Light curves of the components A, B, C and D of Q2237+0305 in the R band. Magnitude is plotted with error bars as a function of time (heliocentric Julian Days -2 450 000).
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[angle=-90,width=13.5cm,clip]{1887ind.eps} \end{figure}$ Figure 5: Resulting V-R colour curves of the components A, B, C and D of Q2237+0305 plotted as a function of time (heliocentric Julian Days - 2 450 000).
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[angle=-90,width=15cm,clip]{1887sta1.eps} \includegraphics[angle=-90,width=15cm,clip]{1887sta2.eps} \end{figure}$ Figure 6: Light curves of four field stars in the V band ( left) and in the R band ( right). Magnitude is plotted with error bars as a function of time (heliocentric Julian Days - 2 450 000). NB: in a few CCD frames (Oct. 16, V; Oct. 16, R; Oct. 19, V; Oct. 19, R; Oct. 21, V; Oct. 21, R; Oct. 23, V; Oct. 23, R; Oct. 30, R; Dec. 9, V), no photometry of star#1 could be derived because its image is truncated by the field border. Moreover, an aberrant point on Nov. 8, R (mag 15.35) does not appear in the star#1 plot.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[angle=-90,width=13cm,clip]{1887fit.eps} \end{figure}$ Figure 7: For both the V ( left) and R ( right) bands, results of the fitted straight line through the B, C and D light curves, after subtraction of their respective mean magnitude ( top). The results of subtracting this average straight line from the previous B, C and D light curves are shown in the middle diagrams. Finally we show in the bottom diagrams the results of subtracting the same straight line from the A light curve.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[angle=-90,width=13cm]{1887VR.eps} \end{figure}$ Figure 8: V-R colour curves for the components A, B, C and D of Q2237+0305 plotted as a function of the V magnitude.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{1887Mod.eps} \end{figure}$ Figure 9: The GLITP-ISIS data (Alcalde et al. 2002) in the V band are shown altogether with the simulated light curve (solid line) using a torus source model (Lee et al. 2005). The logarithmic magnitude scale has been transformed into linear flux units (mJy).
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=8.2cm,clip]{1887Simu.eps} \end{figure}$	Figure 2: An example of CCD frame simulated for the statistical determination of the photometric error bars: the frame corresponds to the same observing date as Fig. 1 (Oct. 29, V).
Open with DEXTER

$\begin{figure} \par\includegraphics[angle=-90,width=13cm,clip]{1887Vban.eps} \end{figure}$	Figure 3: Light curves of the lensed components A, B, C and D of Q2237+0305 in the V band. Magnitude is plotted with error bars as a function of time (heliocentric Julian Days -2 450 000).
Open with DEXTER

$\begin{figure} \par\includegraphics[angle=-90,width=13cm,clip]{1887Rban.eps} \end{figure}$	Figure 4: Light curves of the components A, B, C and D of Q2237+0305 in the R band. Magnitude is plotted with error bars as a function of time (heliocentric Julian Days -2 450 000).
Open with DEXTER

$\begin{figure} \par\includegraphics[angle=-90,width=13.5cm,clip]{1887ind.eps} \end{figure}$	Figure 5: Resulting V-R colour curves of the components A, B, C and D of Q2237+0305 plotted as a function of time (heliocentric Julian Days - 2 450 000).
Open with DEXTER

$\begin{figure} \par\includegraphics[angle=-90,width=13cm]{1887VR.eps} \end{figure}$	Figure 8: V-R colour curves for the components A, B, C and D of Q2237+0305 plotted as a function of the V magnitude.
Open with DEXTER

$\begin{figure} \par\includegraphics[width=8cm,clip]{1887Mod.eps} \end{figure}$	Figure 9: The GLITP-ISIS data (Alcalde et al. 2002) in the V band are shown altogether with the simulated light curve (solid line) using a torus source model (Lee et al. 2005). The logarithmic magnitude scale has been transformed into linear flux units (mJy).
Open with DEXTER