The introduction of the Nautical Almanac in 1767 had required sailors to make use of astronomical time, where the day was reckoned from noon, beginning twelve hours after the start of the civil day. Until then, sailors had used the civil day along with the nautical day. The nautical day also began at noon, but started twelve hours earlier than the civil day. The potential for confusion because of the similarity between astronomical and nautical days was much reduced when on 11 October 1805; the British Admiralty issued an order to end the use of the nautical day. A similar change was made in America in 1848.