A243598 - OEIS

A243598

Decimal expansion of the fraction of the full solid angle subtended by a cone with the polar angle of 10^(-4) arcseconds.

5, 8, 7, 6, 1, 0, 7, 6, 3, 4, 7, 7, 4, 4, 7, 1, 4, 3, 7, 9, 0, 0, 7, 9, 0, 8, 9, 9, 4, 0, 6, 7, 7, 0, 0, 3, 1, 1, 3, 6, 2, 9, 8, 5, 2, 6, 1, 9, 5, 0, 6, 8, 5, 1, 9, 7, 0, 3, 7, 8, 7, 4, 8, 6, 2, 8, 5, 3, 4, 7, 6, 8, 4, 7, 7, 7, 1, 2, 6, 4, 6, 1, 7, 5, 7, 0, 8, 5, 7, 5, 6, 8, 6, 5, 2, 7, 5, 1, 2, 1, 6, 0, 9, 3, 7

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OFFSET

-19,1

COMMENTS

The resolution limit of present astronomical instruments is about 200 micro arcseconds, corresponding to a solid angle cut out by a cone with polar angle of 0.0001 arcseconds. This constant, a, expresses the smallest resolvable solid angle as a fraction of the full solid angle. One might also say that at current top resolution, the full celestial sphere contains 1/a resolvable pixels.

See A234597 for more details on solid angle fractions.

LINKS

Stanislav Sykora, Table of n, a(n) for n = -19..1980

Center for High Angular Resolution Astronomy, CHARA

FORMULA

(1-cos((0.0001/60/60)*(Pi/180)))/2.

EXAMPLE

5.8761076347744714379007908994067700311362985261950685197...e-20

Inverse:

1.7018068118460879832481638181180323127935597506413188919...e+19

PROG

(PARI) (1-cos((0.0001/3600)*(Pi/180)))/2