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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Corrections for latitude when taking sights
From: David Pike
Date: 2019 Mar 13, 09:42 -0700
From: David Pike
Date: 2019 Mar 13, 09:42 -0700
What use is a shot on the PV? The trigonometry now becomes sin Alt=sin Dec/sin Lat.
Brian
I don’t know which impresses me most, your cunning formula or you being up at 04.15LMT to answer us.
So, if your talking about Sin Alt, Dec, and Lat, you’re really looking at Cos Coalt, Codec, and Colat in the PZX triangle.
Sin Az will go to unity and Cos Az goes to zero, so the cosine formula ends up with Cos Coalt = CosCodec/CosColat, which can be written SinAlt=SinDec/SinLat, or something like that.
“Why, it’s just a matter of getting your A, B, and C, and your a, b, and c lined up” said Alice*.
At this rate, I’m never going to get this Appleyard Computer finished. DaveP
*Thanks to: Lewis Caroll, Dickie Richardson, & Frank Debenham.
