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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2015 Jun 25, 01:38 -0700
David Pike forwarded this message from Richard Dunn which includes links to the details from the "Bligh Notebook" in the National Library of Australia. This is the original, primary source evidence from the open boat voyage, and it's clear from the details in it that Bligh had the Ramsden sextant. It's also clear that the sextant's value was small, even trivial, but surely it gave Bligh confidence. Two instruments are better than one, and even in 1789 a metal sextant always trumped a wooden quadrant. It was good for Bligh's morale, albeit irrelevant to navigation. The difference in latitude between sights taken with the "old quadrant" and the "Ramsden sextant" was three miles. That's all. Longitude was estimated entirely by dead reckoning.
Dear DavidMany thanks for the message. I derived this from John Bach (ed.), The Bligh Notebook (Sydney, 1987), esp. the discussion on pp. 26-37, which is a facsimile and transcription of this manuscript in the National Library of Australia:
http://www.nla.gov.au/apps/cdview/?pi=nla.ms-ms5393-1
This includes some instances of observations noted as being from both the quadrant and a sextant, e.g.
http://www.nla.gov.au/apps/cdview/?pi=nla.ms-ms5393-1-s79-v
which has readings with ‘Old Quadt’ and ‘R.B.’ (the Ramsden sextant) and here
http://www.nla.gov.au/apps/cdview/?pi=nla.ms-ms5393-1-s82-v
where it’s noted as ‘Ramsd B’Bach, who also refers to Morrison’s account, states (page 38, note 11)that Ramsden B is one of the three sextants mentioned in his log.
Looking at a transcribed version, there do seem to be some instances from the Bounty log:
http://www.fatefulvoyage.com/logbook/log880215.html
http://www.fatefulvoyage.com/logbook/log880817.html
http://www.fatefulvoyage.com/logbook/log880101.html
Bach also states in the same note that the nook of lat & longs seems to have been a bound collection of extracts of navigation manuals, now in the Dixson library.The Daily Assistant referred to by Morrison is indeed Hamilton Moore.
I’m not aware of the sextant surviving or of its fate after the boat journey.
I hope that helps.
All the best
Richard
Frank Reed
Conanicut Island USA
PS: Richard Dunn mentions a "bound collection of extracts". This was a type of 'book' that we would all recognize today --a collection of pages ripped from various books and "stapled" together into an ad hoc volume. It may be surprising, but these were common in the era, quite analogous to collections of photocopied pages that a modern navigator might assemble. It seems that these homemade books were usually discarded. Also common were manuscript (handwritten) copies of extensive portions of navigation manuals, even whole books. Sometimes it was cheaper and expedient to sit down at a desk and copy a whole book instead of locating and purchasing a copy of one's own. ....a little warning for the collector: manuscript copies of old books are easily forged.