Look To The Skies

 

Praise Be for little old ladies who take once-in-a-lifetime voyag
es through South America, take pictures of just about anything, then write detailed descriptions of what they saw onto each individual slide.

Or Praise Be to Edith for short.

In this case : 

Machu Pichu Sun Dial Knowledge of astronomy was very advanced. Incas had a lunar calendar of 12 months. It is not known exactly how they operated the sun clocks.

OK.

Bonus -