How to calculate Occultation of a Comet by the Moon submitted by Dave Herald Advice for users of Occult 4. To predict such an event, the steps are as follows: 1. From the Ephemeris tab, Comets option, download the latest version of Comet.dat 2. From the Lunar Predictions tab, select Edit user file of minor planets. In the center of that form there is a box to "Import Comets". In the drop-down box, select the comet. Then click 'Import selected from list'. The comet will be added to the end of the list. Now click Save List, to save the updated list of objects - and close the form. 3. From the Lunar Predictions tab, select 'Predictions of single objects'. In the box for Asteroids there is a drop-down box. The comet will be listed in that box. Select the comet, and then 'Find Asteroid'. A list of events involving the comet will be given. You can generate maps and detailed predictions from this list - using the Help file from that form for guidance.]