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While reading more about Trim the cat, I found an interesting item by Matthew Flinders (explorer and cat-o-phile) regarding his Australian longitudes...

 

Some of you may remember that we were talking a while back about correcting lunar longitudes after a voyage. Since the distances in the Nautical Almanac were only barely acceptable in terms of accuracy for many years, it made sense for accurate mapping and charting work to re-do lunar calculations by comparison with actual observations made at Greenwich. I could not point to a specific example of this the last time this came up, but here's one in that cat-happy explorer's own words:

   "The publication in 1814 of a voyage commenced in 1801, and of which all the essential parts were concluded within three years, requires some explanation. Shipwreck and a long imprisonment prevented my arrival in England until the latter end of 1810; much had then been done to forward the account, and the charts in particular were nearly prepared for the engraver; but it was desirable that the astronomical observations, upon which so much depended, should undergo a recalculation, and the lunar distances have the advantage of being compared with the observations made at the same time at Greenwich; and in July 1811 the necessary authority was obtained from the Board of Longitude. A considerable delay hence arose, and it was prolonged by the Greenwich observations being found to differ so much from the calculated places of the sun and moon, given in the Nautical Almanacks of 1801, 2 and 3, as to make considerable alterations in the longitudes of places settled during the voyage; and a reconstruction of all the charts becoming hence indispensable to accuracy, I wished also to employ in it corrections of another kind, which before had been adopted only in some particular instances."

   --Matthew Flinders, 1814.

 

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