astronomy cites

[Laurence Horn]

At 3:06 PM -0600 12/14/04, Mullins, Bill wrote:
>
>annulus
>OED: "4. Astr. A ring of light, as in an annular eclipse. " 1871
>
>Monthly Notices of the Royal Astronomical Society, "Observations of the
>Solar Eclipse, May 15, 1836, by various Observers." volume 3, Number 24,
>June 10, 1836, page 200
>"Mr. Baily gave a verbal account of a remarkable optical phenomenon observed
>by him at the late annular eclipse of the sun, consisting of several dark
>ligaments apparently connecting the borders of the sun and moon, at the
>commencement and dissolution of the annulus."

Well, yes, but does anyone know why "annulus" ('ring') and "annular",
which are from the diminutive of "anus", spelled with a double "n"?
It's not that the astronomers and geometers are or were embarrassed
by the association, is it?  (OED just mentions an "erroneous"
medieval spelling.)

larry