ICDTrack

This text-only addon is useful for calculating the Internal Cooldown (ICD) of trinket procs.

To start tracking a cooldown, you'll need the spell ID fo the prod from wowhead. If you wanted to test the Heroic Starcatcher Compass, you'd find it on wowhead and then click on the buff. Then you start tracking it:

/icd start 109712

As it procs, it will show you the time between procs and let you know when it sees a new best time.