NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Andrew Bauer
Date: 2022 Oct 22, 08:31 -0700
Part 1:
I have occasionally posted news here about the LD tables and charts I have created using Python. Humble thanks for permitting me to do so.
Lunar Distance charts are simply a visual aid and depict the data in the LD tables over the passage of 24 hours for any particular day. First let me draw your attention to the fact that I created the charts with a Plate Carrée projection, originally inspired by Bowditch pages 250-251 (2002 Bicentennial Edition) or 246-247 (2017 Edition).
I was always disappointed with the distortion on a Plate Carrée projection that increases with higher latitudes towards the poles. It is not conformal; local scale varies in every direction (except along the equator); and areas are not comparable. I favour the following quote from Wikipedia:
“The fundamental problem of cartography is that no map from the sphere to the plane can accurately represent both angles and areas. In general, area-preserving map projections are preferred for statistical applications, while angle-preserving (conformal) map projections are preferred for navigation.” (https://en.wikipedia.org/wiki/Stereographic_projection)
Before I proceed, the code is published here:
- in GitHub: https://github.com/aendie/SkyAlmanac-Py3
- in PyPI: https://pypi.org/project/skyalmanac/
Sample LD tables and charts (as previously created) for November 2022:
