Capturing the night sky – A chat with astrophotographer Ralf Rohner

When we first saw Ralf Rohner’s photos of the night sky we were drawn into the way he captured the beauty and magic of landscapes at night and the imensity of night skies. His work unveils the wonders of this universe and allows us a peek at the wonders of the universe.

Ralf is an astrophotographer from Switzerland. He is married and a father of 10 year old twins. He currently works as Captain for SWISS International Air Lines on the Boeing 777-300ER.

How would you describe your photographic style?

Although the major part of my photographic work consists of wide field landscape astrophotography, I have my photographic roots in telescopic deep space imaging. This made me a longtime advocate of using deep space imaging and processing techniques in nightscapes. My photographic style is therefore very technical both in the field and during post processing. I use tracking mounts, modified cameras and narrowband filters to capture my data and my images are the result of dozens, if not hundreds of exposures that are merged in post processing. It is however very important for me that my images show a real scene. This means that the alignment of the sky over the landscape is scientifically correct and that all parts of my images are captured from the same location and during a single night. Of course, the images are not a representation of what the human eye can see, but in my opinion, revealing the hidden beauty in the sky is what astrophotography is all about.

What led you to begin doing night photography?

Already as a kid, I was interested in physics and especially in astronomy. Some 25 years ago, I finally bought my first telescope and I started doing visual astronomy. It didn’t take long until I attached a camera to the telescope and started dabbling with astrophotography. In 2015, we went on a camping vacation in the US Southwest with our kids. As my telescopic equipment was too big to take along, I bought one of the small tracking mounts that started to become available a few years earlier, and that’s how I started with my first nightscapes.

Describe a shot you had to work really hard to achieve.

One of the shots that required quite an effort is my ‘deepscape’ with Orion Nebula setting behind the building on Mt. Saentis in the Switzerland’s Alpstein Mountains:

Such images are called ‘deepscapes’, as they combine classic deep space images with landscapes. They are captured at longer focal lengths than usual for landscape astrophotography and this makes the alignment critical. Correct planning is very important, as a small error in the tripod position can make the deep space target miss the foreground feature.

To capture this alignment, I had to snowshoe for one hour on an icy mountain path with my deep space equipment. The backpack with a heavy tripod, an equatorial tracking head, counterweights, a cooled monochrome camera, an electronic filter wheel, the lens, a computer and a 12V battery pack to power the whole rig weighted roughly 40kg. I slipped and fell twice during the ascent, but fortunately got away with nothing worse than a few bruises.

What is your favorite equipment to have on hand when you shoot and why?

That’s definitely a small tracking mount. These lightweight and easy to set up devices make the camera follow the movement of the stars in the sky and thus allow me to capture long exposures of the night sky without star trailing.

You have photographed some amazing places like Death Valley, the Canary Islands, the Swiss Alps & so many more-what role does exploration play in your photography?

Exploration is very important. Of course, I have to do a lot of scouting to find interesting foregrounds with a good sky alignment, but that’s only part of the story. Exploring these wonderful places and enjoying the solitude in a beautiful natural setting really is the fun part of my photography. For me this was the reason to switch from telescopic astrophotography, where the equipment is too bulky to be carried along, to landscape astrophotography with more lightweight gear that can be taken on a hike.

On the topic of exploration-what is your process of choosing locations to do night photography in?

One important factor certainly is sky quality. You cannot capture a good landscape astrophotograph, if there is too much light pollution. Unfortunately, this rules out many areas that are too close to big cities.

The other important factor is an interesting foreground. Coming from deep space imaging, this is something I first had to learn: A great sky over a dull landscape looks boring, but a less than perfect sky over a stunning foreground can still look great.

Whenever I see a good daylight landscape photo, I ask myself if this scene can be captured in connection with an interesting astronomical target. Fortunately, there are excellent remote planning apps, like e.g. PlanIt for Photographers, which help you answer this question. If I decide that a place would be worth a visit, I mark it with a flag on Google maps and save the planning in my app.

What is the most interesting object in the sky you have ever photographed (or the most interesting one you want to photograph)?

The most interesting object I ever captured certainly is a Quasar named Q1227+120. It actually is a chance find in one of my deep space images of Markarian’s Chain, a galaxy chain in the constellation Virgo. The quasar is at a mindboggling cosmological distance of 19.2 billion light years, almost at the edge of the observable universe. The light of this quasar was emitted 11.1 billion years ago. That’s 4/5th of the time that has elapsed since the big bang! Its image, however, is not pretty, as the quasar is only a bright dot among the stars, but it is definitely there.

Something I would really like to photograph is the southern sky. There are lots of interesting targets, like e.g. the Magellanic Clouds. These dwarf galaxies are orbiting our Milky Way galaxy, but are not visible from the northern hemisphere. I was able to capture them from the airplane, but for real good quality, I have to shoot from the ground.

I read that you have been a pilot for over 25 years.Do you think your experience as a pilot has shaped your photography in any way?

Yes, of course. The most obvious photographic output from my job as a pilot, are my airborne astro-lapse movies and the astro or aurora images captured from the flight deck. My airborne astrophotography has become quite popular over the last years and brought me some nice publications.

Another aspect of being a pilot is that I travel a lot. Sometimes, I can even do my photography during one of my layovers abroad, which is a nice bonus. With a different profession, I certainly wouldn’t have been able to shoot as often or in so many different places.

You experiment with a lot of different techniques in your night photography. If you were going to tell an aspiring night photographer one technique that would help them achieve better results, what would that be?

Maybe I am using all these exotic techniques, because I have to keep the technical edge to make up for lack of artistic talent… LOL

Most aspiring astrophotographers are starting with a camera on a tripod. If they are not aiming for star trail images, they have to limit exposure times to avoid star trailing. Even with a fast lens, this means that they have to use high ISO settings, which makes single exposures look very noisy.

The problem is, however, not the high ISO setting, but the lack of signal due to the short exposure time. Fortunately, there is a remedy for that: Stacking several identical exposures is a standard technique in astrophotography to increase the signal-to-noise ratio and thus make the image look much cleaner.

Of course, the stars will move in an untracked sequence of sky images and stacking these images would lead to star trails, similar to a single long exposure. There are, however, software solutions that align the stars before stacking (Sequator for Windows, freeware / Starry Landscape Stacker for Mac, $40).

My recommendation therefore is to shoot a sequence of 7-10 exposures in immediate succession and stack them in one of the above mentioned programs before further processing. Stacking can also be used to reduce noise in night landscapes or cityscapes without stars.

Have you ever seen a ufo (or photographed one)?

No. I have seen a few things I couldn’t immediately explain when I saw them, but further research always yielded an explanation based on atmospheric science or human technology.

How can our readers help to support your work?

It would be nice if some of the Learn Photography Skills users would choose to follow my work on my social media channels and if they really like one of my images, they can order prints under ralf-rohner.pixels.com.

See more of Ralf’s work:

Website: https://ralf-rohner.pixels.com
Facebook: https://www.facebook.com/skypointer2000
Instagram: https://www.instagram.com/skypointer2000
Flickr: https://www.flickr.com/skypointer2000
YouTube: https://www.youtube.com/channel/UCQUe0ltXdp0dh-RdM80jzCQ