https://web.pa.msu.edu/people/horvatin/Astronomy_Facts/
constellation_pages/leo.htm
https://www.messier-objects.com/messier-objects-byconstellation/messier-objects-in-leo/
http://www.seasky.org/constellations/constellation-leo.html
https://twitter.com/Unistellar/status/139836551865507430
9/photo/1
Subra