NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Lunars and pixels
From: John Huth
Date: 2010 Dec 11, 14:54 -0500
From: John Huth
Date: 2010 Dec 11, 14:54 -0500
Since this was discussed extensively just a little while ago, I thought I'd share the experience of some of my students in doing lunars with pixels. Some of the trials and tribulations may sound familiar to some of you.
They calibrated their pixel width using stars in Leo, and then did a Sunset - Lunar time difference and did shots of the Moon and Regulus. One of the bigger issues was pixel bleeding - in order to get a decent image of Regulus, the disk of the Moon became overexposed and quite fuzzy. They only did as well as 5 degrees in longitude using this, and their conclusion was that navigators "back in the day" had to have considerable patience to do lunars.
Here are some of the other projects they did
clepsydra
orientation of saxon and norman churches
viking sun stone
map-making using the techniques of Lewis and Clark
Latitude and longitude from sunset/sunrise and meridian passage
Accuracy of backstaves
Nocturnals
Construction of a sun compass
Latitude and longitude from satellite dishes
All of them had to do some statistical analysis of their results. I was pleasantly surprised by some of the results. In particular, I was amazed at the accuracy of the sunstone. They used some optical quality calcite, and used it to find north at sunset. They were systematically off in their measurements, and were perplexed until I pointed out that the sun was (is) setting south of due west this time of year. When they put this in, the measurements were spot -on. As we talked about before, one doesn't know if sunstones were really employed by the vikings. I'm simply pointing out that they do work, and I was surprised at how well they did.