SunGraph 3.7.2 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. We recommend checking the downloaded files with any free antivirus. The application lies within Lifestyle Tools, more precisely Weather. The actual developer of this free software for Mac is Robert R. Urschel.
From the developer:
SunGraph is a sunrise and sunset calculator showing sunrise and sunset times for anywhere in the world and for any day of the year. For any latitude, the earliest and the latest sunrise and sunset times will be displayed. The tool displays the equation of time along with the inclination of the sun above the horizon at transit. A world view shows the location of the sun on the Earth for the current time, or any day of the year.
You may want to check out more Mac applications, such as Dwarf Fortress, Eldy or Tide Graph, which might be related to SunGraph.