I'm trying to figure out exactly when I can no longer get vitamin D from the sun for this year. I am referencing this chart http://aa.usno.navy.mil/data/docs/AltAz.php
I read somewhere on PR that when the sun altitude is below 50, you can't make vitamin D. But using that number and the chart linked above makes "vitamin D winter" where I live start much earlier for me than mainstream sources seem to say it does. Does anyone have a link to definitive info about what altitude the sun needs to be at in order to be able to produce vitamin D from it?
(I understand the altitude of where you live also plays a part, I'm taking that into account.)
I read somewhere on PR that when the sun altitude is below 50, you can't make vitamin D. But using that number and the chart linked above makes "vitamin D winter" where I live start much earlier for me than mainstream sources seem to say it does. Does anyone have a link to definitive info about what altitude the sun needs to be at in order to be able to produce vitamin D from it?
(I understand the altitude of where you live also plays a part, I'm taking that into account.)