Gosh, I wonder what 'secret' society built the concrete arch-gravity 'Hoover Dam' and put this 'star map' with angels on it? Maybe they left a few clues?

"Hoover Dam" = 47 (Full Reduction)
"Star map" = 47 (Reverse Full Reduction)
A big number to the Masons.

The Masonic compass sits at 47 degrees and it represents 'time', connecting to the angel, err, I mean 'angle' that the tropic of Cancer and Capricorn sit parallel with the equator. Both are 23.5 degrees north and south of it, making them 47 degrees apart.
A star map, eh, all about documenting the passing of... 👇
"Time" = 47 (English)

That circle at the top of the compass is called the... 👇
"Pole star" = 47 (Reverse Full Reduction)
...representing the Sun and its angel, err, 'angle' of light (the 47 degrees). Light and time are very much connected.

"Time" = 144 (Jewish)
"Light" = 144 (Jewish)
12 hours of day, 12 hours of night.
12x12=???
12 moonths.