I have a friend who lives near Buenos Aires, Argentina who loves to photograph the sky day and night. Her name is Piqui Díaz, and she often shares images of clouds and night-sky scenes taken with a basic cellphone on Facebook. For many, a smartphone is our only camera, and while it produces surprisingly good photos in daylight, night shots — without additional software or a high-end phone — are trickier.
But with care and determination it’s amazing what you can do. Díaz recently used her phone and the working half of a pair of broken binoculars to take photos of the asteroid Vesta and the planets Uranus and Neptune from her light-polluted suburban location. Sitting as still as a statue she positioned her phone against the lens and held her breath during each 8-second exposure. The slightest movement and the stars would streak. Because the stars were too dim to show on the phone screen she had to carefully aim the instrument to the right location and shoot blind. Her work stands out as a superb example of what a beginning astrophotographer can accomplish from compromised skies with the bare minimum of equipment.
Díaz’s recent photo of Orion caught my eye because it showed how odd the constellation looks to northerners when viewed from the southern hemisphere. In a word — upside-down! The three belt stars look familiar, but the rest of the constellation appears askew. That’s not all. Orion is in the northern sky in the southern hemisphere. When you turn to face it, east is on your right and west on the left. As the constellation rises and sets, it moves from right to left across the sky instead of left to right as viewed in the northern hemisphere.
The same is true of other sky scenes including the recent moon-and-planet alignment. In the northern hemisphere, the ecliptic, the path taken by the sun, moon and planets across the sky, tilts to the south at dusk this time of year. As you might guess by now, it tilts north from the southern hemisphere, a fact demonstrated nicely by the side-by-side views (above) from Florida and Ezeiza.
If you get in a car or plane and travel south from the northern hemisphere, all the stars in the southern sky slowly move upward to the north. Take Orion the Hunter. It stands about halfway up in the southern sky from U.S. and European latitudes. But travel in Orion’s direction and the constellation climbs higher and higher in the southern sky. Sky-wise vacationers in the Caribbean are often amazed at how high the Hunter stands. If you fly all the way to the equator the constellation will shine from directly overhead!
Continue your journey below the equator to the southern hemisphere to faraway Buenos Aires or Darwin, Australia and Orion slides past the zenith (overhead point) into the northern sky. To see it you must turn completely around and face north, and when you do, the constellation appears upside down. And by the way, only on a spherical Earth are such changing perspectives possible. If the Earth were flat Orion would only appear in one place in the sky no matter where you viewed it from on the planet.
But here’s the weird thing. People who are used to seeing Orion with his legs in the air think it’s perfectly normal and rarely imagine the constellation any other way. They also associate Orion with summer, not winter like we do in the north. Our Orion? Completely upside down and totally weird. Not to mention you have to put on 5 pounds of clothes to appreciate it!