anon-140

Here is the latest SCLK kernel for the mission: http://naif.jpl.nasa.gov/pub/naif/DEEPIMPACT/kernels/sclk/DI... and if you are not among the JPL/NAIF/SPICE cognoscenti and don't have the numbers sense to grok it from that file, here is one of the SPICE required reading files: http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/req/sclk.ht... to get you started. SPICE is one of the most robust, well-commented and -documented toolkits I have ever seen. There is more information about the spacecraft clock in the PDS archives e.g. http://naif.jpl.nasa.gov/pub/naif/pds/data/di-c-spice-6-v1.0...