1. - Given that the radius of the Earth's orbit is ≈1.49×1011 m and that 1 light-year ≈9.461×1015 m, explain Bessel's calculation that 61 Cygni is about 10.3 light-years away.
2. - Modern estimates place 61 Cygni at about 11.4 light-years away. Calculate a more accurate value for the parallax of 61 Cygni.