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Re: Bligh's noon by chronometer
From: Jeremy C
Date: 2010 Jun 3, 07:46 EDT
From: Jeremy C
Date: 2010 Jun 3, 07:46 EDT
Gary wrote:
I've never understood the slavish devotion to catching the sun at the
exact highest point. If instead you work the noon sight as a normal LOP
sight using the normal tables (HO 214 etc.) you have a four minute
period when you work the sight with an LHA of zero and an AP within 30
NM of the DR and this method produces an LOP of the normally expected
accuracy.
gl
============================
My guesses:
1) easy to understand/visualize
2) easy to reduce (1 book, 1 stick figure, add/subtract)
3) easy to plot (1 horizontal line, no AP needed)
4) not overly time critical
5) not DR critical
6) fairly easy to shoot.
I had to laugh when you referenced HO 214 as a "normal table." In 17
years I've only seen one person use it at sea and only a few more who might know
what it was. "Normal" since the 1970's has been HO 229. That being
said, i have a nearly complete set of HO 214 (0-70 degrees) but would like to
find a digital copy of the set, if one exists, to compile into a single volume
pdf such as i have done with HO 229 so that i can carry it with me on my
computer. For the record, i prefer HO 214, especially for star
identification despite having to use meridian angle (t) instead of straight
LHA.
Jeremy
