title: How can I compute sunrise/sunset times?
body: <p>I like to keep track of sunrise and sunset times.  For the past couple of years I've been doing this with a small program written with a popular library for my favorite programming language.  The last two months I've been keeping track of these times more regularly than usual, and I happened to notice that on the day of the equinox the sunrise time jumped eight minutes as compared to the day before!  I knew this was impossible and compared with <a href="http://aa.usno.navy.mil" rel="noreferrer">NOAA</a>, finding out that my rise and set times had been off for several days and in fact seemed to be off by about a minute for most of the year.</p>
  
  <p>At this point, I'd like to just implement the calculations myself.  What algorithms or formulas are available to do this computation?</p>