ACSN was privatized in 1980, and its name was changed to The Learning Channel in November of that year; the name was subsequently shortened to "TLC. " (NASA immediately launched NASA TV as the ACSN's internal replacement. ) The channel mostly featured documentary content pertaining to nature, science, history, current events, medicine, technology, cooking, home improvement, and other information-based topics. These are often agreed[by whom?] to have been more focused, more technical, and of a more academic nature than the content that was being broadcast at the time on its rival, The Discovery Channel. The channel was geared toward an inquisitive and narrow audience during this time, and had modest ratings except for the boating safety series Captain's Log, produced and hosted by Mark Graves, a. k. a. Captain Mark Gray. Captain's Log aired weekly in primetime on TLC from 1987 to 1990. It achieved between a 4. 5 to 6 share in the ratings and was the highest compensated series in the history of TLC with over 30 times the compensation of any other TLC series.