A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Sean C
Date: 2019 Sep 16, 22:35 -0700
The weather was fine after I saw the halo. I guess it's not a totally reliable indicator. As for whether it was a halo or a corona: I'd say it looked much more like the pictures of a halo than those of a corona. In fact, I'd say it looked almost exactly like this picture from the Wikipedia page on halos that you linked to.
Right after I saw it, I tried to remember as best I could the appearance of the one I had seen previously. I estimated both to have a radius of about seven to ten moon diameters - which is right in line with your analysis. But judging arc distances by eye - or even through the likely distortion prone lens of a cell phone can be tricky. I suppose it's kind of funny that I was standing there trying to estimate the distance when I had a precision device for measuring it right inside my door. But the thought of using it never even occurred to me. Ha! I guess I was so preoccupied with admiring the sight and trying to get a decent picture that it totally slipped my mind. Anyway, the halo (or corona or whatever) was not even visible just a couple minutes later - so I'm not sure if I would have even had time to make a measurement.