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The data has been taken from \cite{Potter_2011}. All timing stamps are in BJD using the TDB time scale. No further transformations needed. A total of 42 timing measurements exist. However, Potter et al. have discarded data points. See their text for details. In this analysis I will consider the full set of timings as a start. Later the analysis chain can be repeated with any discarded timing measurements.  \section{Linear ephemeris - fitting a straight line using LINFIT}  In general I am using IDL for the timing analysis. The cycle or ephemeris numbers have been obtained from IDL> ROUND((BJDMIN-TZERO)/PERIOD) where BJDMIN are all 42 timing measurements, TZERO is an arbitrary timing measurement that defines the CYCLE=$E$=0 and PERIOD is the binary orbital period (0.087865425 days) and was taken from \cite{Potter_2011}, Table 2. In this work I will use TZERO=BJD 2,450,021.779388. It is a bit different from the TZERO used in Potter et al. (2011).  As a first step I used IDL's LINFIT code to fit a straight line with the MEASURE\_ERROR keyword set to an array holding the timing measurements errors (Table 2, 3rd column, Potter et al. 2011). This way the square of deviations are weighted with $1/\sigma^2$ where $\sigma$ is the standard timing error for each timing measurement. The average or mean timing error for the 42 measurements is 6.0 seconds. Also I have rescaled the timing measurements by subtracting the first timing measurement from all the others. Rescaling introduces nothing spooky to the analysis and has the advantage to avoid dynamic range problems. This is in particular needed for a later analysis when using MPFIT. Using LINFIT the resulting reduced $\chi^2$ value was 95.22 ($\chi^2 = 3808.82$ with (42-2) degrees of freedom) with the ephemeris (or computed timings) given as \begin{equation}  T(E) = BJD~2450021.77890(6) + E \times 0.0878654291(1)   \end{equation} 
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