What Is The Difference Between The Local Equator Vs Local Horizon In Starry Night Pro Plus 8? (Answer: Read On!)

Hi All. I'm trying to determine the exact upper limb azimuth for a historical sunrise at sea level using white sky, but am having a hard time figuring out the difference between Alt-Az 'local equator' and Local View 'local horizon'. I presume it has something to do with atmospheric refraction, but can't get my head around it. Essentially, at Stonehenge on July 18th 3000 BCE, the upper edge of the sun will appear to rise over the 'Local Horizon' at azimuth 48.236 at 4:40:27 AM, while it rises over the 'Local Equator' at azimuth 49.174 at 4:45:16 AM over the 'Local Equator'. Presuming Stonehenge was at sea level, which sunrise on July 18th would the observer in 3000 BCE actually see? The sun rising over the 'local horizon' or the sun rising over the 'local equator'?  Any feedback would help. Thanks, Carl