Apophis in the new Synodic Orbit Visualisation Tool

The intricate pattern representing the path through space of the asteroid Apophis depicted using ESA's new Synodic Orbit Visualisation Tool.

The tool keeps the Sun at the centre and Earth located in the X-axis, approximately one astronomical unit from the Sun. The resulting reference system allows the helpful display of visibility regions that depend on a telescope’s visual magnitude.

Based on the absolute magnitude of a near-Earth object (NEO) and the limiting visual magnitude of a telescope, the tool displays a yellow balloon-like shape known as the ‘detection polar’. This 3D surface provides the geometrical location of the points – the limits – where the NEO would become visible using the selected telescope. When the NEO is outside of this surface, it is not observable with such a telescope. If the object path enters this detection polar, the object would then become visible. 

The tool creates beautiful shapes when representing the motion of an NEO in this reference system, the figures reminiscent of the Spirograph. They provide an improved and more intuitive understanding of how and when an object may be observed.