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A,B, P etc - BigBill - 11-12-2017
Does anyone know or have a link that explains what exactly the values for A,B, F, P etc represent in a sight reduction?
I was asked recently and I know anything with H has to do with altitudes and the Zs are azimuths but the rest I don't know with enough certainty to pass on.
Thanks
RE: A,B, P etc - Rumata - 11-12-2017
(11-12-2017, 04:35 PM)BigBill Wrote: Does anyone know or have a link that explains what exactly the values for A,B, F, P etc represent in a sight reduction?
I was asked recently and I know anything with H has to do with altitudes and the Zs are azimuths but the rest I don't know with enough certainty to pass on.
Thanks
BigBill, maybe it refers to Ageton method ? Or there is another one, just called S-tables method which used smartly developed tables and can be used for any latitude.
Also, in Dutton, composite sailing. Another remote possibility is the analysis of deviation. It includes 6 coefficients: A,B,C,D E,J. See Bowditch for details. Unless those letters represent angles and sides of the spherical triangles ( which I think they are), I don't know any other instance where I saw those letters regrading sight reduction.
RE: A,B, P etc - BigBill - 11-13-2017
(11-12-2017, 08:19 PM)Rumata Wrote:(11-12-2017, 04:35 PM)BigBill Wrote: Does anyone know or have a link that explains what exactly the values for A,B, F, P etc represent in a sight reduction?
I was asked recently and I know anything with H has to do with altitudes and the Zs are azimuths but the rest I don't know with enough certainty to pass on.
Thanks
"BigBill, .... Unless those letters represent angles and sides of the spherical triangles ( which I think they are), I don't know any other instance where I saw those letters regrading sight reduction."
Thanks. That's what I was thinking but I didn't want to pass on bad information. These are the values being looked up in the Nautical almanac.
RE: A,B, P etc - Rdutton - 11-14-2017
(11-12-2017, 04:35 PM)BigBill Wrote: Does anyone know or have a link that explains what exactly the values for A,B, F, P etc represent in a sight reduction?
I was asked recently and I know anything with H has to do with altitudes and the Zs are azimuths but the rest I don't know with enough certainty to pass on.
Thanks
BigBill,
Just a guess but maybe the P stands for the elevated Pole as in the geographical North pole projected into space?
I know there are the A, B, C tables and perhaps that applies to Nories?
Roland
RE: A,B, P etc - craigsl - 11-15-2017
(11-14-2017, 11:51 PM)Rdutton Wrote:(11-12-2017, 04:35 PM)BigBill Wrote: Does anyone know or have a link that explains what exactly the values for A,B, F, P etc represent in a sight reduction?
I was asked recently and I know anything with H has to do with altitudes and the Zs are azimuths but the rest I don't know with enough certainty to pass on.
Thanks
It's not Ageton which deals only with A, B and I think R.
L typically is Latitude and P is Parallax.
Take a look at Bowditch Chapter 24 The Sailings-
Bowditch Chapter 24- The Sailings
Maybe that'll help?
Craig
RE: A,B, P etc - Rumata - 11-16-2017
Yes, it doesn't look like from Ageton' method, despite the fact that in that method A,B, C, R, K, L, H are used ( yes, in the table itself, just A,B, and K. Others are for the intermediate results.) I'm still inclined to believe that those are the sides and angles of a spherical triangle. Bowditch, Chapter 14. And, if it is for the sight reduction process, what else it could be, except for the well-known just few methods? The basis for all those is a spherical triangle and the sin and cos formulas to solving the sides and angles. Just my humble opinion.