NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Lewis and Clark. was: sextant practice and time keepers
From: George Huxtable
Date: 2010 Sep 18, 21:55 +0100
From: George Huxtable
Date: 2010 Sep 18, 21:55 +0100
Hewitt Schlereth wrote- "One of the good things about celestial is you can learn all you need to know without going to sea - just ask Lewis or Clark." Lewis and Clark may well be icons of American history, but they should not be held up as examples of celestial navigation. They may have been competent leaders of a military expedition into then-alien lands. Their dead-reckoning along the river may have been workmanlike. But as celestial navigators, they were inept. It wasn't really their fault. Wich no experience of navigation between them, Lewis was pitched into a crash-course on celestial navigation with the astronomer Robert M Patterson, in Philadelphia, before the journey started. He was provided with a handwritten document, Patterson's "Astronomical Notebook", which he carried throughout the great journey. It was not at all "user-friendly", and did not address the special requirements of a land-navigator. I have made a transcript of its contents available, with an explanatory commentary, at- http://www.hux.me.uk/lewis01.htm After leaving Philadelphia, Lewis had no other source of navigational advice. When Clark joined, he was instructed by Lewis, so it was a case of the blind leading the blind. I have made a detailed analysis of the early part of their journey, in http://www.hux.me.uk/lewis02.htm . This covers their ascent of the Mississippi, from its junction with the Ohio, near modern Cairo, to winter near its junction with the Missouri, close to St Louis. From this point, the expedition proper commenced, up the Missouri. So these were their days of self-learning about navigation, in which they would make every conceivable blunder. Unfortunately few of those errors were recognised, and most continued right through the voyage. As a result, not one of their deduced positions was ever correct, and even simple latitudes were grossly in error. So, fine explorers they may have been, and they certainly made a momentous journey. But Lewis and Clark should not be held up as exponents of celestial navigation. George contact George Huxtable, at george{at}hux.me.uk or at +44 1865 820222 (from UK, 01865 820222) or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. ----- Original Message ----- From: "Hewitt Schlereth"To: Sent: Saturday, September 18, 2010 6:04 PM Subject: [NavList] Re: sextant practice and time keepers | Good Afternoon, Alan - | | Well, welcome to a quaint old art. It's always heartening to see a new mind | engaged by it. | | I'm curious about the sextant you're using and what sight reduction method. | | Also be interested to know what general (landlocked) part of the world you | are in. One of the good things about celestial is you can learn all you | need to know without going to sea - just ask Lewis or Clark. | | Hewitt | | On Sat, Sep 18, 2010 at 12:46 PM, Alan wrote: | | > For reasons unknown, during the last few years I became interested in | > celestial navigation, strange as that might be, for I'm not a | > boating/sailing type. | > | > In any case, getting "good" with a marine sextant requires practice with | > the thing, an activity that living inland makes difficult. A while back, | > looking though a Celestaire catalog, I came on the Davis Artificial Horizon, | > and purchased one. They also offer a Practice Bubble Horizon that mounts on | > the sextant. I have yet to obtain success with the latter, though he former | > works, assuming that one reads the brief instruction sheet that comes with | > it. | > | > Working against a Known Position (GPS coordinates), my calculated fix | > (estimated position) often falls well within 5 NM of KP. Granted, I'm not on | > a small boat, bouncing all over the place, however granting that, one can | > get about as much practice as they can stand with the Davis Artificial | > Horizon. | > | > As to time keepers, a while back I purchased a Casio G-Shock Atomic Watch, | > via Amazon. Paid about $50.00 for it. The thing is, and remains dead nuts | > on, as far as I can determine via checking with Official Time via computer, | > time data coming from The Naval Observatory. | > | > For the sake of clarity, aside from being, in a small way, a customer, I | > have no connection with either Celestaire or Casio. | > | > | > ---------------------------------------------------------------- | > NavList message boards and member settings: www.fer3.com/NavList | > Members may optionally receive posts by email. | > To cancel email delivery, send a message to NoMail[at]fer3.com | > ---------------------------------------------------------------- | > |