This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Bianchini's meridian line with solar disc. Francesco Bianchini's meridian line with solar disc in the basilica Santa Maria degli Angeli dei Martiri Rome gnomon in the basilica's south wall projects the sun's image onto the line every solar noon Here the image is minutes before local noon at an angle of nearly degrees from the zenith