Main Caviar graphical interface, showing part of an image from the Cassini wide-angle camera (W1559467979_1.IMG). In this example, the main image has been zoomed by a factor of two (the zoom factor is user-selected). Predicted positions of any known satellites or planets within the field of view, based on SPICE ephemerides, are shown in yellow. Predicted catalogue star positions are shown in red and blue: stars labelled in red were successfully detected within the image, while those in blue, although within the field of view, were not detectable. When the cursor is within the main image window, the small zoom panel at the lower right follows the cursor position. The position of the cursor is labelled in real time, showing image coordinates, in addition to right ascension (RA) and declination (Dec), and radial distance from the centre of the primary body (Saturn in this case). This small zoom window disappears when the refresh button is pressed (second button from top right) to reveal the additional tool buttons hidden underneath.