NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Formulas to Compute LHA
From: Lu Abel
Date: 2009 Jun 28, 09:15 -0700
From: Lu Abel
Date: 2009 Jun 28, 09:15 -0700
Will Ross, in a later post, mentioned the United States Power
Squadron's celestial nav courses (there are two of them and they are
more accurately "offshore navigation" classes, GPS and even
computerized voyage planning have been added to traditional celestial).
They have a well-organized sight reduction form that includes a time diagram.
You can download it at http://www.usps.org/national/eddept/n/files/sr96a.pdf The front side includes all corrections going from hs to Ho, calculating the GP of the body, and then a Law of Cosines reduction to Hc. The back side includes a form for calculating Hc using the NASR method.
If you read Chapter 15 of Bowditch (available on-line), there is a pretty comprehensive explanation of how to draw a time diagram. Or, as Will suggests, take the USPS course(s).
Lu Abel
Bill wrote:
They have a well-organized sight reduction form that includes a time diagram.
You can download it at http://www.usps.org/national/eddept/n/files/sr96a.pdf The front side includes all corrections going from hs to Ho, calculating the GP of the body, and then a Law of Cosines reduction to Hc. The back side includes a form for calculating Hc using the NASR method.
If you read Chapter 15 of Bowditch (available on-line), there is a pretty comprehensive explanation of how to draw a time diagram. Or, as Will suggests, take the USPS course(s).
Lu Abel
Bill wrote:
Andrew wrote regarding time diagrams:I am interested in this diagram, where can I find it?I am not certain this is what you are looking for as it is not called "time diagram", but the attached does make LHA a bit more digestible for me. It is from Susan P. Howell's book "Practical Celestial Navigation" which I purchased from Celestair. Other texts I own (but are sadly in storage far away) may use the same diagram but in the opposite rotation. The end result is the same. A question for the list. When teaching at Purdue I recall copies from a book could me made for educational purposes, and "deju duh" (the Indiana version of "deju du) causes me to think there was a limit on the number of copies. Am I skirting violation of copyright law by postings excerpts? If so, would it be legal to send just one copy off list? Thanks Bill B --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---