OFFSET
17,1
COMMENTS
The distance for which 1 AU (approximately the mean radius of the Earth's orbit around the Sun) subtends an angle of 1 arcsecond.
The value is exactly 149597870700 m / tan(Pi/(180*3600)) since it is defined in terms of the astronomical unit, whose length was defined in 2012, see A163103. - M. F. Hasler, Oct 14 2014
This constant is algebraic of degree 86400. - Charles R Greathouse IV, Oct 31 2014
In 2015 the parsec was redefined to be exactly 648000/π astronomical units, so this sequence no longer gives the current value of a parsec, which is now given in A292525. - M. F. Hasler, Sep 18 2017
Although the definition has changed, this sequence is preserved in the OEIS for historical reasons. - N. J. A. Sloane, Oct 14 2017
LINKS
International Astronomical Union, 2012 Resolution B1
J. S. Calcut, Rationality and the Tangent Function, as of Oct 12 2006.
Wikipedia, Parsec
EXAMPLE
1 parsec = 149597870700 m / tan(Pi/(180*3600)) ~ 3.085677581 * 10^16 meters.
MATHEMATICA
RealDigits[ 149597870700 / Tan[Pi/648000], 10, 111][[1]] (* Robert G. Wilson v, Nov 17 2014 *)
PROG
(PARI) 149597870700/tan(Pi/180/3600) \\ Then use eval(Vec(Str(%))) or digits(%\.1^99) to get the digits. - M. F. Hasler, Oct 14 2014
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Arkadiusz Wesolowski, Oct 06 2014
EXTENSIONS
More terms from M. F. Hasler, Oct 14 2014
STATUS
approved