I’ve been away from the blog for a few months, and part of the reason was I went on a vacation to South America. Tonight, May 24, you can see the crescent moon just after sunset in the western sky. The moon lies very close to the two brightest stars of Gemini, the twins Castor and Pollux (Pollux is the one on the left, slightly brighter and yellower than its twin). Brilliant Venus will also be visible, but much closer to the horizon.
Thinking about the crescent moon reminded me of the unusual (to a North American) sights of the Southern Hemisphere sky. Yes, I expected to see stars and constellations that are impossible to see here in Chicago (for example, the Southern Cross, and Alpha Centauri). What was truly odd, however, was seeing familiar sights in the sky, but backwards (or upside down). The constellations of Orion, Canis Major, and Leo were all upside down. And the moon was backwards:
After sunset, the crescent moon looks like the sketch on the left in Buenos Aires, but it looks like the sketch on the right in Chicago. In the northern hemisphere, the sun and the moon (and everything else) rise in the east, circle around to the south, and set in the west. Well, in the southern hemisphere, the sun and moon also rise in the east, of course, but they circle around to the north (because it’s the south pole that is visible in the sky, not the north) before setting again in the west. Thus, to northern eyes, everything looked backwards!