This is a movie of the Sirius A+B binary star system. The initial frame of the movie illustrates the geometry of the system. Click "Start" at the bottom of the frame to begin the animation. Once the animation begins, there is a row of buttons in the control panel at the bottom. Their functions are easily deduced, but a detailed explanation is given below. Button Functions: These buttons control how different elements of the movie are displayed: 'Hide Orbits' hides the two orbits but not the stars; button label changes to 'Show Orbits'. 'Hide Sirius A' hides only Sirius A (but not its orbit); label changes to 'Show Sirius A'. 'Hide Sirius B' hides only Sirius B (but not its orbit); label changes to 'Show Sirius B'. 'Hide C.M.' turns off display of the system's center of mass; label changes to 'Show C.M.'. 'Show Info' displays informational text and labels; button label changes to "Hide Info'.

Exit and Speed: Click 'Exit' to leave the animation and return to the opening frame of the movie. The left and right arrows on either side of the 'Exit' button toggle the speed of the animation down or up, respectively, one step for each click.