Flat Earth Math | Sight Reduction Tables Spreadsheet in realtime! @FlatEarthMath | Uploaded February 2022 | Updated October 2024, 4 hours ago.
I've been learning about celestial navigation, and discovered that the process doesn't end with the Nautical Almanac and sextant readings, it actually uses a process called "Sight Reduction." On the ocean, navigators can use Sight Reduction Tables to help in the process. I decided to try to duplicate the tables using home-grown methods (based on spherical trigonometry, specifically the Spherical Law of Cosines).
https://msi.nga.mil/Publications/SRTMar (my source for the tables)
0:00 Intro to the Table
4:17 The Celestial Triangle
12:57 Spherical Law of Cosines
16:06 Starting the Spreadsheet
24:54 CoDec, CoAlt formulas
28:16 Hc, d in decimal form
30:11 Formatting Hc
35:00 Formatting d
37:30 Azimuth formula
48:40 “CONTRARY” Hc, d, Z
55:07 “SAME” but opposite LHA
1:02:49 Eliminating negative Hc
1:08:42 Final spreadsheet
Please excuse all the mistakes, part of the challenge was to see if I could do a complete spreadsheet in about an hour, in realtime, with no script and no cuts. I did a few notations on-screen, but my errors are there for all to see, and some are cringe-worthy. Sorry! :-)
Here's my end result, as a Google Sheet. Feel free to download a copy to your Google Drive and mess around with it! :-)
docs.google.com/spreadsheets/d/1mHIy1UdDOzPphFdQNwePx1lgwbWmo_W8HDMXa-a9heA/edit?usp=sharing
Please check out a complete celestial navigation course at @The Nav Station. And thanks to @roohif for giving me my starting values for my challenge.
I've been learning about celestial navigation, and discovered that the process doesn't end with the Nautical Almanac and sextant readings, it actually uses a process called "Sight Reduction." On the ocean, navigators can use Sight Reduction Tables to help in the process. I decided to try to duplicate the tables using home-grown methods (based on spherical trigonometry, specifically the Spherical Law of Cosines).
https://msi.nga.mil/Publications/SRTMar (my source for the tables)
0:00 Intro to the Table
4:17 The Celestial Triangle
12:57 Spherical Law of Cosines
16:06 Starting the Spreadsheet
24:54 CoDec, CoAlt formulas
28:16 Hc, d in decimal form
30:11 Formatting Hc
35:00 Formatting d
37:30 Azimuth formula
48:40 “CONTRARY” Hc, d, Z
55:07 “SAME” but opposite LHA
1:02:49 Eliminating negative Hc
1:08:42 Final spreadsheet
Please excuse all the mistakes, part of the challenge was to see if I could do a complete spreadsheet in about an hour, in realtime, with no script and no cuts. I did a few notations on-screen, but my errors are there for all to see, and some are cringe-worthy. Sorry! :-)
Here's my end result, as a Google Sheet. Feel free to download a copy to your Google Drive and mess around with it! :-)
docs.google.com/spreadsheets/d/1mHIy1UdDOzPphFdQNwePx1lgwbWmo_W8HDMXa-a9heA/edit?usp=sharing
Please check out a complete celestial navigation course at @The Nav Station. And thanks to @roohif for giving me my starting values for my challenge.
