| | Ring_Polar | The representation of ring data requires a unique projection. The rings are modeled by a thin disk centered on the body and in its equatorial plane. For Saturn, the thin disk is centered on Saturn and in its equatorial plane, with an outer radius of 500,000km. If the field of view falls partially or completely beyond this limit or if it intersects the primary body before intersecting the rings, the data will not be included. For Cassini CIRS (composite infrared spectrometer), the plotted coordinates are derived as follows. If A is the location of the intersection of CIRS field of view with the body's equatorial plane, the X coordinate is the distance of A from the center of the body (e.g. Saturn), and the Y coordinate is the local time on on the body at the intersection with the body's surface of the line between A and the body's center. Local time is expressed in fractional hours, from 0.0 (at midnight) to 12.0 (at noon), to 24.0 (at midnight). |