Plotting an ellipse w/ 15 points; need to find best fit curve

[astronomer]

I have problems with plotting an ellipse. I have 15 points with coordinates and I have to plot best curve through points. The curve is ellipse, it is rotated and it's center is in (0,0). Do you know any computer programs for plotting like this? Thank you for help

 

[tkhunny]

One traditional way is to find the foci and the fixed length that is the sum of the distances from both foci.