... Armagh Observatory, College Hill, Armagh BT61 9DG, +44 (0)28 3752 2928 . The distance of the Sun from Earth is the basic unit of all astronomical distances. ... The 18th century transits of Venus allowed a proper geometrical determination of this unit to be made for the first time. ... One of the most famous of these problems is the black drop effect. ... They calculated the mean distance to the Sun to be 95 million miles whereas the currently accepted value is close to 93 million miles. ...

... Fortran . ... The final example shows the program in the new programming language F. program tpk(input,output); (* Pascal program for Unix *) var i : integer; y : real; a : array [0..10] of real; function f (t : real) : real; begin f := sqrt(abs(t)) + 5*t*t*t end; begin for i := 0 to 10 do read(a[i]); for i := 10 downto 0 do begin y := f(a[i]); if y > 400 then writeln(i,' TOO LARGE') else writeln(i,y); end end. ... C THE TPK ALGORITHM C FORTRAN IV STYLE DIMENSION A(11) FUN(T) = SQRT(ABS(T)) + 5.) ...