I'm developing a C++ computer library with the formulas in the book "Practical Astronomy with your Calculator or Spreadsheet 4th Edition" but I have a problem with the formula 49, "Sunrise and sunset": I don't get the same results than in the book.
The example in the book say:
Calculate the times of sunrise and sunset (upper limb) over a level horizon at sea-level on 10 March 1986, as observed from Boston, Massachusetts, at longitude 71.05º W and latitude 42.37º N. We shall take the Sun's angular diameter to be 0.533 degrees, its horizontal parallax to be 8.79 arcseconds, and the refraction due the atmosphere as 34 arcminutes and, having added on half of the Sun's angular diameter and a small correction for parallax, we arrive at a total vertical shift at the horizon of the upper limb of 0.833333 degrees. The time zone correction is -5 hours.
In the book:
Rise: 6h 6m 0s Set: 17h 43m 0s
With my implementation:
Rise: 6h 4m 2.98s Set: 17h 39m 41.28s
I've been searching to find online calculator to check if the book is wrong or I am wrong. I've found some but I can't get any conclusion because each of them returns a different value; i.e, if I have tried three, I get three different values for sunset and sunrise.
So, I have searched to find the formulas that these online calculator uses without success. I've been searching for the formulas adopted by the IAU but, again, without success.
Where can I find those formulas?
The online calculators are:
I repeat my question because it seems that there is something that it is misunderstood:
Where can I find the formulas adopted by the IAU?