Fans of NASA’s Astronomy Picture of the Day might have noticed Friday’s installment: a stunning shot of the southern sky over Iguaçu Falls, as seen from deep in the Brazilian side of the national park surrounding the falls.
—Picture copyright Babak Tafreshi (TWAN)
I was lucky enough to get in touch with the astrophotograher who snapped the shot, Babak Tafreshi, a photographer, science journalist, astronomy communicator, and award-winning creator of The World at Night (TWAN) project.
Babak graciously answered a few questions for me—which appear below, lightly edited—about his experience in Iguaçu Falls and the technical challenges of capturing so many night-sky objects in a misty rain forest.
1. What brought you to Iguaçu Falls? Was this your first visit?
I was invited for an astronomy conference in Brazil in Rio state, but visiting Iguacu was my long-time dream. I have been to Victoria Falls in Africa and Angels Falls (picture) in the Amazon too, and being at night at Iguaçu was my goal. So I started contacting the national park officials a few weeks before to get permission to stay there overnight. They were worried I might encounter jaguars!
2. The Iguaçu park seems pretty remote, especially at night! Did you run into any unique challenges—or weird wildlife—while making the picture?
Yes, there were challenges to make TWAN photos here, besides the long travel. The area is very wet at this high-water season, and working at night with long exposures close to the falls kills the camera easily, and it’s often foggy and cloudy.
It’s not possible to wonder around the national park overnight without special permission. Another challenge was dealing with wandering jaguars. There were a couple of onça-pintadas (a kind of jaguar) reported seen in the area a few days before I arrived.
Staying in front of the roaring giant falls at night with the southern Milky Way and the Magellanic Clouds in front of me and dense rain forest at my back was an experience to remember. Any sound from the trees was bringing thoughts of how to meet a jaguar at night! But they didn’t show up, although there were lots of activities in the woods!
After three nights of overcast sky, the clear sky came. It didn’t last more than few hours, but it was enough for a successful night adventure in this paradise.
3. What kind of camera and settings did you use? What time did you start, and how long was the exposure?
I used two DSLR cameras as usual, an old Canon 20D for time-lapse videos (which will be released soon) and a 5D for still shots and panoramas. I have modified my 5D for nighttime imaging. I have replaced its built-in IR-cut filter with an astronomical one, as the original filter cut a lot of stars and nighttime environment lights.
This specific shot is a panorama of four stitched shots all made by a 28mm lens and by one-minute exposure. I have also used a star tracking drive on my tripod to make a bit longer exposure without having startrails [streaks of starlight created by Earth's rotation]. Near the center along the horizon are lights from Argentina’s Iguazú Falls International Airport.
I started the session before sunset with setting up everything, and it took a few hours until I got a good result. I was in the area for four nights, finding locations and waiting for clear skies. I was hoping to get much closer to the falls (something like this) but it was too wet with raining mist and the clear sky didn’t last long, so maybe next time!
4. How many of the objects in your picture are visible only from the Southern Hemisphere?
All in the left half of the picture are mainly visible from the Southern Hemisphere or northern equatorial regions, including the Southern Cross, Alpha and Beta Centauri, and the Magellanic Clouds.
The star Canopus is technically visible from below 35-degrees North latitude, but many people in the Northern Hemisphere miss it because it’s usually so close to the horizon.
5. Were you surprised by any of the objects visible in the frame?
The Small Magellanic Cloud was mostly behind the clouds and suddenly appeared for a short time, and I was fascinated to capture both galaxies in one shot.
6. What’s your top tip for anyone interested in doing their own astrophotography?
Besides technical information on nighttime photography, learning about the night sky is an important key. A successful landscape astrophotographer should be in the right place at the right time.