Overview
This application streamlines the traditional "intercept method" of sight reduction. Unlike standard calculators that hide the math, this tool combines a high-precision internal almanac with a Digital H.O. 229 Table Simulator, allowing students and navigators to verify their manual sight reduction steps directly on screen.
Key Features
H.O. 229 Simulator
A pixel-perfect simulation of the sight reduction tables. Displays the exact Page (LHA), Latitude, and Declination grid used for reduction, including interpolation logic.
AP Assistant
Automatically calculates the mathematically correct Assumed Position (AP). It adjusts your longitude to ensure an integer LHA, a critical step for manual table entry.
Integrated Almanac
Calculates GHA, Declination, SD, and HP on the fly for any second in time using J2000 algorithms. No physical books required.
Digital Workflow
Follows standard USNO/H.O. logic with auto-corrections for Index Error, Dip, Refraction, and Parallax. Data is persisted automatically.
Interactive Plotter
Visual plotting sheet with running fix capability. Handles date-aware advancement of LOPs for fixes spanning across midnight.
Star Finder
"Identify" mode scans the sky for bodies within 2° of your observed altitude, perfect for identifying stars in twilight.
Technical & License
Architecture: React 18, Tailwind CSS, Astronomy Engine. Delivered as a single HTML file for completely offline portability.
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY.