NavList:

From: Gary LaPook <glapook@pacbell.net>
Subject: [NavList] Re: help with sun sights
To: NavList@navlist.net
Date: Saturday, January 15, 2011, 11:37 PM

I have to add that using H.O. 249 volume 2 and 3 is the same as using H.O. 229 but using H.O. 249 volume is different but easier once you know how it works. But volumes 2 and 3 cover all latitudes and all bodies up to 30° declination. This means that you can work the sun, moon, planets and 31 of the 57 listed stars. You can't use H.O. 249 volume 2 and 3 for 10 stars with high northern declinations or 16 stars with high southern declinations. Volume 1 though lets you use many of these additional stars but with a different procedure. I have complete sets of H.O. 249, H.O. 229, H.O. 214 and H.O. 218. gl --- On Sat, 1/15/11, Gary LaPook <glapook@pacbell.net> wrote: From: Gary LaPook <glapook@pacbell.net> Subject: [NavList] Re: help with sun sights To: NavList@navlist.net Date: Saturday, January 15, 2011, 4:43 PM H.O. 229 takes up a lot of space and is heavy and provides more precision than is actually needed for small craft navigation. H.O. 249, Sight Reduction Tables for Air Navigation,  is much more compact and the arrangement of the tables is more convenient. Both tables are used the same way (with the exception of the second differences correction for slightly greater accuracy for high altitude sights in H.O. 229 that you can skip if you choose) so if you can work one set of tables you can work the other. I suggest you download H.O. 249 from this site: http://msi.nga.mil/NGAPortal/MSI.portal (click on "Publications") print out a few pages and compare with your H.O. 229. You can check your work by having the Navy do the computations here: http://www.usno.navy.mil/USNO/astronomical-applications/data-services/cel-nav-data Since you are just getting started, and before you head gets polluted with these other complicated methods, I suggest you try the flat Bygrave slide rule which you can make for yourself at a cost of a few dollars with the printouts available here: https://sites.google.com/site/fredienoonan/other-flight-navigation-information/modern-bygrave-slide-rule https://sites.google.com/site/fredienoonan/other-flight-navigation-information/self-contained-long-term-celestial-navigation-system The Bygrave computes everything your need in less than two minutes and uses no batteries. gl --- On Sat, 1/15/11, Patrick Goold <goold@vwc.edu> wrote: From: Patrick Goold <goold@vwc.edu> Subject: [NavList] Re: help with sun sights To: NavList@navlist.net Date: Saturday, January 15, 2011, 2:15 PM Gary, I am using HO 229.  Patrick On Fri, Jan 14, 2011 at 10:22 PM, Gary LaPook <glapook@pacbell.net> wrote: "I am still unclear how to read the reduction tables. Thanks so much!" Which tables are you using? gl ---------------------------------------------------------------- NavList message boards and member settings: www.navlist.net/NavList Members may optionally receive posts by email. To cancel email delivery, send a message to NoMail[at]navlist.net ---------------------------------------------------------------- -- Dr. Patrick Goold Department of Philosophy Virginia Wesleyan College Norfolk, VA 23502 757 455 3357 Charles Olson: "Love the World -- and stay inside it."