Guest Blog: Chilean skies through the camera lens

Posted by Alison Klesman
on Friday, March 16, 2018

Fig 1. Milky Way from Obseravatorio Astronomico Andino. // All Photos: Matthew Dieterich

By Matthew Dieterich

Instagram: @mattdieterichphotography

Click on the links in the text for extra images and larger versions of those shown here. 

I have been passionate about astronomy and night sky photography since 2006. Over those 12 years, I became fascinated with the most advanced telescopes in the world. During that time I found education and outreach to be an excellent medium for me to share my passion for astrophotography with the general public.

Far from cities where the night sky is pristine for studying the universe, the allure of visiting a professional observatory has been a common theme in my daydreams. I knew I had to find a way to visit one of these jaw-dropping locations for astrophotography. To this end, for three years I applied to an astronomy education program that traveled to world-renowned observatories in Chile. In 2017, my goal of joining the Astronomy in Chile Educator Ambassadors Program (ACEAP) was finally reached. As an ACEAP Ambassador, I would join a team of 8 astronomy educators from the U.S. to visit the most powerful telescopes on Earth.

Chile is the astronomy capital of the world and the U.S. has invested a lot into reaching that milestone. Our goal as ACEAP Ambassadors is to educate our communities about the science underway at these astronomical research facilities. Educating the U.S. public about the benefit of such an investment is important for increasing our nation’s science, technology, engineering, and mathematics (STEM) fields. Over the coming decade, additional groundbreaking facilities will be constructed in Chile and their discoveries will further advance our STEM capabilities as a society.

Fig. 2 : Milky Way from Cerro Mayu Observatory.

Our nine-day expedition began in Santiago, where we were briefed on how to maximize our presentations and outreach impact. With this knowledge in hand, we first visited Observatorio Astronomico Andino, which is a public observatory outside Santiago. That evening was my first experience seeing the Southern Milky Way, a view I had only in my dreams until that night (Fig. 1). To capture the view, I setup my Nikon D750 on a tripod and tossed on a 24mm lens. I set my aperture to F/1.4, shutter speed to 15 seconds, and ISO to 3200 to soak in the light of my first Southern Milky Way exposure. Needless to say, I was overwhelmed by the Southern Milky Way’s beauty after viewing the Northern Hemisphere’s counterpart for decades.

Fig. 6: Milky Way over CTIO.

Fig. 7: Panorama of sunset over the Andes from CTIO.

After a few days in Santiago, we flew north to the coastal town of La Serena. We enjoyed presentations from knowledgeable astronomers, engineers, and educators at the Gemini Observatory Headquarters. Later that evening our team headed to another stunning public observatory, Cerro Mayu Observatory. We had time to soak in the stars and I managed to capture a panoramic view of the Milky Way (Fig. 2) over a statue on the observatory grounds. I used my Nikon D750 and 24mm F/1.4 lens to manually capture 16 images for the panorama using 15-second exposures at ISO 5000. The following day, we headed into the mountains to visit the 4.1-meter Southern Astrophysical Research (SOAR) Telescope (Fig. 3) and 8-meter Gemini Observatory (Fig. 4). Watching both of these massive instruments move as the telescope operator slewed them around the observatory was incredible!

Fig. 4: Myself standing in front of the massive 8-meter Gemini South telescope.

Located on the neighboring mountain from Gemini, Cerro Tololo Inter-American Observatory (CTIO) was our home for the next three nights. We were fortunate enough visit with professional astronomers while they conducted their research with the 4-meter Blanco telescope (Fig 5).  Afterwards, I wanted to capture a panorama of the Milky Way over CTIO (Fig. 6). The 30 mph (50 kph) winds on the mountain forced the observatory to close, but I managed to keep my tripod stable long enough to capture a 20-image panorama. I setup my Nikon D810a with a 24mm F1.4 lens and collected 15-second exposures at ISO 5000. The thrill of viewing the RAW files on the camera with the Milky Way arching over the observatory was amazing! I knew this was going to be a memorable image. The old adage of “the best camera is the one that’s with you” rang true when I didn’t have my DSLR with me at dinner and sunset erupted into a beautiful magenta filled sky. The only camera I had on me was a small Sony RX100, but the resulting images blew me away! I hand-held shot a panorama as the magenta light hit the snowcapped Andes (Fig. 7) and then quickly ran over to capture an image of the observatories backlit by the sunset’s glow (Fig. 8). Thankfully, I was glad I had this small point-and-shoot camera from Sony in my pocket to capture the best sunset I have ever seen.

When I thought the trip couldn’t get any better, we headed to our final location in the Atacama Desert. Unlike the previous observatories where we visited optical telescopes, we were about to tour telescopes that captured radio waves to study the universe. The Atacama Large Millimeter/submillimeter Array (ALMA) is the most powerful radio telescope in the world and is located in an incredibly harsh environment for a reason (Fig. 9). The benefit of building ALMA in one of the most arid deserts in the world and at an elevation of over 16,000 ft (5,000 m) means that the radio telescopes have less interference from the Earth’s atmosphere. Equally as impressive as the radio telescopes at 16,000 ft, the night sky in the Atacama was the best I have witnessed. I have never seen the Milky Way core brighter than during our three nights in San Pedro de Atacama. Merely a few miles outside San Pedro, I used my Nikon D750 and 24mm F/1.4 lens to capture a short 8-second photo at ISO 10,000 of the Milky Way (Fig. 10). That same evening, I captured a panorama of myself under the Milky Way (Fig. 11). I captured 8 photos with a Nikon D810a and 24mm lens using 15 second exposures at ISO 5000 to create the panoramic view.

Fig. 9: Myself standing in front of a few radio antennas at the ALMA site.

Being able to visit many of the world’s most powerful telescopes in person was nothing short of a dream come true. A fitting end to my time in Chile concluded with a photo I wanted to capture for years, the Milky Way from a plane (Fig. 12). I had the row of seats to myself, so I setup my Nikon D750 and 14mm F/2.8 lens on a tripod. To minimize movement of the plane’s speed, I had to shoot fast 5-second photos at max ISO, 51,200. The resulting photo of the Milky Way from 40,000 ft over Chile was an excellent way to finalize my trip.

Fig. 12: Milky Way from 40,000 ft in an airplane over Chile.

In closing, I hope that my outreach as an ACEAP Ambassador will inspire members of the next generation to follow career paths in STEM, just as similar images of space inspired me.

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