NavList:

Hello Navlist experts. I have caught the lunar bug and have been studying Cook's journals. 2 questions please.
1) Cook and astronomer Charles Green did several accurate longitudes from eclipses of Jupiter's moons (especially June 29th 1770, when grounded up the Endeavour river). I can't get better than several minutes (time )error with a cheap but reasonable 4 inch refractor. Has anyone else tried this with more success and have any tips? do I just need a better telescope? I'm getting much better results with lunars, even on a moving boat,than with jupiter on terra firma.
2)Cook mentions several lunar distance observations towards the end of the voyage, after Green had died. eg May 21st 1771 he says" Long 24 deg 50 mins, 2deg 28mins west of account". This suggests he was using LDs for navigation even in 1771?(Frank earlier suggested the calculations may have been done later on return to England) My question is, Did he have a Nautical almanac with 3 hourly LDs up to 1771 to do the quick 30 minute clearance method? I thought he only had 1768-70.If not, he or someone else on board (not Green) must have used the 4 hour Maskelyne Mariners Guide method? Has anyone tried this? all help appreciated. Francis
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