NavList:

Hello everyone, although I've been lurking around quite a bit these past few weeks, this is my first post on this site. I've been a sailor for decades but took up celestial navigation only recently and I'm finding it fascinating. I'm sure I still have a lot to learn but I was able to perform my first fix from the snowy beach at our lake house two weeks ago and I was within 2 miles (call it beginner's luck). I found the process of sight reduction to be quite tedious and lengthy and was looking for a way to make it easier and to do away with the Almanac and sight reduction tables. I found several mobile apps and computer programs to do it, but apps imply using a GPS-equipped device to plot a celestial fix, which doesn't feel right, and I think computers are too cumbersome and fragile, so I wondered if I could program my good old HP Prime calculator to do it. It turned out that it IS possible and that it actually works quite well, but it took a LOT more effort than I ever anticipated, especially to calculate the ephemerides. I have made the source code and instructions available in this Github repository and I would welcome anyone to inspect, critique, and contribute to the code base.

With this, I am able to plan observations, look up ephemerides, perform sight reduction and graphically plot a fix, all on the calculator, so all I need to plot a position is a sextant, a watch, and the calculator.

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