A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Position-Finding
From: Tracy Shrier
Date: 2018 Jan 7, 21:02 -0800
I've been meaning to post this for a while. Took these sights right after the Navigation Symposium, but then got busy with training in early December, then the Holidays.
To further introduce myself to the NavList community: I am a CRJ pilot for a U.S. regional airline. I'm periodically taking sights from the flight levels to recreate Cel Nav techniques of the '40s. I am self trained using Weem's 1943 Air Navigation, the Navy's '40s Air Navigation series, a U.S.N 1945 Air Navigators Handbook, and a later H.O. Pub. No. 216. I am using a Link A-12 sextant and I want to particularly acknowledge the gracious assistance recieved from Mr. Robert Swartz to get it working. It was quite an honor to present results to date and the Navigation Symposium in November and Frank has posted my slides at fer3.com/mystic2017/. Generally, I am taking 2 minute sights with the A-12, trying to trigger a hs tick every 10 seconds. I've calibrated the A-12 to a water horizon and Polaris, interpolating IC from there. I'm using the Air Almanac and Pub. 249 for data and sight reduction. And I'm doing everything old school - paper, 'whiz wheel' nav computers, etc., and then comparing to my FMS (flight management system). As I generate what I consider to be new milestones with this project I'll post the results here for your interest and feedback.
On this night we were flying form MSP to GTF with Alphecca right on our nose. For the first time I was able to get two speed lines that matched the FMS! Also got a satisfyingly accurate three star fix.
Plot 1 - Apphecca speed lines. plotted without coriolis correction as the lines are near perpendicular to track. first and last sight, 27 min. and 170Nm apart give accurate ground speed!
Plot 2 - Alphecca, Altair, and Formalhaut. plot of calculated average of hs. Z-coriolis corrected once from the triangulated fix.
Plot 3 - plot from the visual average of the hs ticks on the A-12 disk.
Reduction - reduction worksheet
Sight data - hs readings, averages, and sight notes.