One of my most powerful memories from childhood is of sitting back in a large, old theater chair and looking up into the dome above as a planetarium projector (looking for all the world like a mutant ant on steroids) made the stars and planets wheel overhead.
My father was a planetarium lecturer. Not a very common trade: there are perhaps a hundred or two in the country, a thousand around the world. Dad ran the planetarium at Santa Monica College, and lectured part time at the Griffith Observatory for over twenty-five years.
A planetarium, for those unfamiliar with them, consists of a dome and a projector designed to be able to project up onto the dome the stars as they would appear at any given night within the last few thousand years -- or the next few thousand. You can see the stars as they would appear at any time, at any point on the world. A good, old fashioned star projector is a wonder of mechanical engineering. Star balls at each end contain a light source and thousands of carefully placed pin-pricks, focused by lenses, to project the stars in their correct place and brightness. Separate geared projectors show the planets as they follow their procession along the ecliptic, against the background stars.
The old lecturer's console up at Griffith (shown to the left, with the projector looming in the background) was a wonder of switches and dials encased in massive thirties-era woodwork. The lecturer, armed with a script, a dim reading light, and a laser pointer brought the lights down and summoned up the stars. There was always a brief "star talk" in which the lecturer pointed out the night constellations currently visible in the early evening, which planets were currently visible, and any upcoming astronomical events. Then the "feature" part of the show followed, which might cover anything from the anniversary of the moon landings, to the martian lander, to the set of conjunctions which may have been the "Star of Bethlehem."
These days, most planetariums used "canned shows". The movements of the projector and automated, and a pre-recorded voice gives exactly the same lecture every time. No wonder they're not very popular. As recorded entertainment goes, planetarium shows don't compete. But back then at least, Griffith shows were always life, with each lecturer giving the standard script his own flavor.
I wish I could claim that I'd retained more from those many afternoons and evenings under artificial skies. I can still identify a half dozen constellations and find Arcturus and generally know what planet I'm looking at in the early evening, but that's about it. Mostly, I have memories of bouncing in theater seats, looking at the ranks of dials, certain pieces of music that sound like stars coming out to me, and the tones of my father's voice as he walked the audience through the universe.
Réquiem ætérnam dona eis, Dómine. Et lux perpétua luceat eis.