A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Jeremy C
Date: 2021 Sep 30, 02:26 -0700
Recently I found myself in the Yellow Sea dodging an erratic Typhoon. I had never been up there before and was pleasantly surprised to find a much better horizon than I was used to seeing in the East China Sea. I am attributing that to the warmer water there.
In any case, I had a young 3rd mate and an AB who had also recently graduated. In a mixture of observations and teaching we did some sunlines and crossed them with LAN while they were on watch. We were a bit late on one of the LAN observations, so I decided to show them how an ex-meridian worked. It was a bit of an academic exercise since we were up around 35N so the few minutes we were late resulted in a correction of only 0.1’ in Latitude. I did the reductions both by hand and also with my Celsticomp V. Sadly the Celesticomp is older than both of my students.
I didn’t bother with a plotting sheet, instead opting to draw the LOP’s directly on the paper chart we still keep. I am sure they were just humoring me by pretending to pay attention, but it certainly demonstrated that the GPS was at least in the ballpark.
While we were underway, I also used Frank Reed’s GPS Anti-spoof app to assist them in their azimuth duties (and hopefully inspire some sales for Frank). They found it much easier to find gyro error by hitting the “pause” button on the phone app rather than typing in all the information into the computer for calculation.
I also used Frank’s app to shoot LAN. I waited until the exact moment the AZ read 180 and took my observation. It certainly made the process much quicker than waiting for the sun to hang and “calling noon.”
Sadly we were prevented from shooting stars by clouds at twilight, but hopefully we will have a bit better weather when we get underway sometime next month.