That Viking sunstone theory might be oversold

I read a paper from a researcher at University of Oslo who tested calcite crystals against a standard magnetic compass. They found the accuracy was only within 20 degrees on overcast days, not the pinpoint navigation people claim. Has anyone else looked at the actual lab data on this?

2 comments

2 Comments

the_anthony1mo ago

Oh man, I see it differently actually. That 20 degree figure comes from a really specific lab setup with low-grade calcite, not the high-quality Icelandic spar that would've been available.

wells.karen1mo ago

Get some quality Icelandic spar and do the measurement yourself, you'll see the difference is night and day. The cheap lab stuff they use in those studies has all kinds of impurities that mess with the refraction angles. I actually ran into this problem when I was trying to replicate a polarization experiment for a class project. Swapped in a proper piece of spar and suddenly everything lined up with the old texts. People get too hung up on numbers from modern equipment without accounting for the material quality.