A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Lunar stuff (was: Calculating accurate apparent-angles between stars)
From: William Allen
Date: 2003 Jan 8, 12:35 -0800
From: William Allen
Date: 2003 Jan 8, 12:35 -0800
George, I for one will be very appreciative of any work you can provide and I will wait as long as it takes. I can only imagine how time consuming this must be! And I agree that we hope Bruce will take to heart the serious interest that many of us having in not only using his book of tables but also understanding the theory behind the tables. As for the targetted lunar epoch, I would suggest that we aim for the heyday of lunars, which might be just before chronometers become widely available at reasonable prices. Would this be a period around 1800 to 1850? I'm not as expert on this as many of the other members, but this is my first thought. Without the benefit of the Cotter book, I am wondering what year did Borda (and others) first publish his (their) methods? Thanks for the reminder about the various Cotter books. I own the History of the Sextant, but you are right, there are other navigation titles written by this Cotter. I am trying to get the History of Nautical Navigation from my library. The prices mentioned by other helpful members seem a bit steep. Regards, Bill -----Original Message----- From: Navigation Mailing List [mailto:NAVIGATION-L@LISTSERV.WEBKAHUNA.COM]On Behalf Of George Huxtable Sent: Wednesday, January 08, 2003 2:47 AM To: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM Subject: Lunar stuff (was: Calculating accurate apparent-angles between stars) Bill Allen said. in a thread: Calculating accurate apparent-angles between stars >I have been silently following the lunar discussion with fascination for the >last year or so. You might say I am on the lunar-tic fringe. It has surprised me how many listmembers with an interest in lunars have bobbed up to the surface over the last year. It's been most gratifying. >I agree with George and his assessment of our needs for some detail behind >Bruce's tables (which I own and have used, but like many, I wish I knew the >rationale for what I am doing). I hope, and think, that Bruce is hearing these messages. >Also, George, I really appreciate the write-ups you did explaining lunars. >Am I correct that there are only 4 parts or have I missed number 5? Thank you, Bill. You are quite correct, sorry to say. I would be deeply embarrassed about the situation, if I were the embarrassable kind. It's become a family joke, here. >I don't know if you >had given any thought to going back through these and making any additions >or corrections that might apply. Well, what's on the stocks just at the moment is a revision of part 4, in particular that section that deals with the possibility of calculating predicted altitudes of the Moon and other-body, instead of measuring their altitudes. This is a point that I got quite wrong in the original message, and have been steered in the right direction by helpful interventions from listmembers, for which I am most grateful. I'm going to be off-watch, away from this coming Saturday 11 Jan for about 6 weeks, and it's touch and go whether I can complete this revision and get it out to the list before then. I will if I can. The intention is to tie up the series in a final message (or maybe two) after my return in late Feb. Whether this good-intention prevails over other commitments and a certain natural indolence, remains to be seen... The aim then will be to tie together all the parts of a lunar observation, up to deducing the longitude. One problem is this: lunars play no part in present-day navigation, so anyone making lunar observations nowadays is, to some extent at least, delving into the past. But what period in the past? The historical aspect becomes important, because the details of nautical tables, and indeed the way navigators have thought about their position-finding, have changed very significantly over the years. To some extent at least these changes will need to be reflected in the final part (or parts) of my series about lunars, when it appears. The intention is that it WILL appear, and I appreciate the occasional nudges from listmembers such as Bill, encouraging me to finish the thing off. ========================= Now for Cotter's book on "A history of Nautical Astronomy". Don't order the wrong book: he wrote several others on nautical technology, including a good one on "A history of the navigator's sextant". I am glad that my listing of errors to be found in Nautical Astronomy hasn't put off potential readers. I bought my copy about 3 years ago, which had to come from the US, at about $90, as I remember. I put it on the Abebooks waiting-list, where it languished for about 3 months before a copy turned up. Don't give up; it's worth waiting for, in spite of its defects. ======================== By the way- We will be away in New Zealand, and this is the story behind it. I come from a big family, the oldest of seven siblings, and my youngest sister Syl is over 20 years younger than me. She has cohabited with her New Zealand partner for 16 years, producing two now-teenage daughters. Now, for some reason, they have decided to get married. Not one to rush into things, our Syl. So a lot of Huxtables are travelling to Christchurch, and as the bridegroom is also one of a large family, it's going to be a big and enjoyable shindig. Or it will be, if President Bush doesn't manage to set the world on fire in the meantime. George Huxtable.