I've also been wondering how thick the ring will be. Your numbers seem to correlate to the number on the NASA map called Magnitude; I am assuming that is the percentage area that is covered? For Knarraville it's 0.967. If that is indeed for the area then then diameter would be the square root of that, or 0.983, correct? So 1.7% is uncovered and the ring thickness is half that, or about the number you give. However, on the USNO site they have a number called Obscuration, which sounds like the right number, and for Cedar City it is 87.3%. They don't have Knarraville, but they also have the same Magnitude number for Cedar City that the NASA site has, 0.963. So which is it? There's quite a big difference there. If the Magnitude was for the diameter then the area would be 93.5%, so that's not it. On Wed, May 9, 2012 at 3:51 PM, Brent Watson <brentjwatson@yahoo.com> wrote:
This morning's calculations were made in a hurry, and I mistook minutes of arc for seconds of arc. The ring will actually have a thickness of 15.75 seconds of arc (1/4 minute of arc). That is still pretty small, but larger than my morning erroneous calculation. The solar diameter on the 20th during the eclipse is 31.558 minutes of arc. The ring thickness will be only 0.83% of the diameter.
Now for the excuse: I had to hurry off to a class this morning. I must have gotten a bit smarter in the class. This shows the need for peer review. Anyone feel like checking this calculation?
From: Brent Watson <brentjwatson@yahoo.com> To: Utah Astronomy <utah-astronomy@mailman.xmission.com> Sent: Wednesday, May 9, 2012 7:46 AM Subject: [Utah-astronomy] Annular but not by much
This looks to be annular only by a very small margin. My initial calculations show the the uncovered disk of the sun will be a ring only 1/4 second of arc thick. Does this jive with other's calculations? If this is correct, it will be very interesting to see what that small amount of sunlight will do to destroy the view of the corona and prominences. If anything is visible, it will be only fleeting. Perhaps Baily's Beads will be the star of the show. _______________________________________________ Utah-Astronomy mailing list http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy
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