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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Lunar distance method of Chauvenet
From: Paul Hirose
Date: 2020 May 26, 12:07 -0700
From: Paul Hirose
Date: 2020 May 26, 12:07 -0700
On 2020-05-26 8:00, Roger W. Sinnott wrote: > But I'm curious why you are > setting delta-T (or, ET - UT) equal to +10 seconds. According to the > 2020 Astronomical Almanac, delta-T was +7.6s at 1855.0 and +7.7s at 1856.0. I'm not surprised there's a discrepancy. My delta T model is based on the paper by Morrison, Stephenson, and Hohenkerk, "Measurement of the Earth's rotation: 720 BC to AD 2015." http://fer3.com/arc/m2.aspx/Delta-T-long-term-formula-Hirose-feb-2018-g41332 According to the table at the UK HO site, +10 s is about right. For convenience I rounded the value from my model to the nearest integer. http://astro.ukho.gov.uk/nao/lvm/
