Czech astronomer has international impact with night sky images

Zodiacal arc over La Silla, photo: Petr Horálek

Czech astronomer Petr Horálek started his career at the Academy of Science’s Astronomical Institute. During this time, he fell in love with astrophotography, becoming one of the most respected Czechs in the field. He is one of the photo ambassadors of the European Southern Observatory in Chile and several of his pictures were featured as NASA’s Astronomy Picture of the Day. Horálek specializes in capturing rare night-sky phenomena and hopes that his unique shots will draw attention to the problem of light-pollution.

Petr Horálek,  photo: ESO / P. Horálek,  CC BY4.0
When I met with Petr Horálek, I first asked him to tell me what triggered his interest in night time photography:

I started my professional career as an observer of fireballs at the Ondřejov observatory. It was a very interesting job but also a little bit boring, because all I had to do was to look after a lot of cameras. So I was looking for something I could do in the meantime.

“I bought a new camera to shoot some time lapses for my documentary about the night sky, but I eventually realised it would take years to finish the film. In the meantime, however, I took a lot of pictures with and this is how I became an astrophotographer.”

I guess that the Czech Republic is not the best place for astrophotography, because there is a high level of light pollution.

“It is, unfortunately, and it is not just a problem for those who want to enjoy the night sky. We know that it also affects people around the world: their health, as well as economy and ecology. So there are so many negative effects of light pollution.

“My way to deal with the problem is to travel far away from Europe to places with no civilisation. I try to get the most beautiful pictures of the night sky to show people what they are missing due to light pollution.”

So what are some of the best places in the world to take pictures of night sky?

“These parts of Chile are very far from the city and the light pollution is very low. So it’s like being closer to the universe.”

“I said that Europe was one of the worse places in the world in terms of light pollution, but of course the conditions are not bad everywhere. You can find some beautiful spots for instance in Slovakia, Ukraine or the Alps.

“But of course if I travel somewhere further, I try to find places with no population. There I can the Milky Way just like nowhere else, because I can see it even beyond the horizon, which would be impossible here.

“I can also capture some unique phenomena, which are quite common, but are not easy to capture them due to air pollution, such as air glow, the natural emission of our atmosphere.

How did you learn the skills of taking pictures of night sky?

“When I started in 2011 I spent months researching the Internet. But there are so many ways to do it and to post-process the pictures.

“One of the best people I have ever met is Professor Miroslav Drückmiller from Brno, who has pioneered a mathematical way of post-processing images.

“He became very famous in the world for his photos of solar eclipses. He uses his mathematical mind to get the best information out of every pixel, which is what we are all trying to do in astrophotography.”

How important is equipment in astrophotography? I imagine it plays a crucial role.

Zodiacal arc over La Silla,  photo: Petr Horálek
“Of course, along with weather conditions and location. For example I use a full frame Cannon 6D camera which is modified. Usually these cameras are fitted with a filter in front of the sensor that are human eye sensitive around the green colour.

“But the universe doesn’t lie only in green colour and shines in lot of colours. So I removed the filter and replaced it with a different one, which allows the camera to be sensitive in the whole visible spectrum, from red to blue, so the pictures are somehow more colourful. The other crucial thing is to have good lenses.”

Is there any particular time of the year which is more favourable for taking pictures of the night sky?

“It depends on where you take the pictures and what you are taking pictures of. But the most favourable season everywhere in the world is from April to the end of October, when the central part of the Milky Way is the most visible. A lot of people all around the world take fantastic images at this time of year.”

In 2015 you were appointed one of the 27 ambassadors of the European Southern Observatory? What does that mean?

“I try to get the most beautiful pictures of the night sky to show people what they are missing due to light pollution.”

“It is a huge honour for me and I have the wonderful privilege that I am one of the 27 people who are allowed to get to the ESO observatories in Paranal and La Silla at night time.

“These observatories are open for the general public during the day but only the photo ambassadors are allowed to be there, which is the best thing about it.”

The observatories are regarded as one of the best places in the world to observe night sky. Why is that?

“They are located in dry mountain desert called Atacama and there are very particular conditions. It is very dry, so you don’t have to worry about humidity, which is one of the biggest problems for astronomers and photographers.

“It is in higher altitudes so you don’t have to care about dust and other problems related to lower altitudes. This is the most important thing. You can do what you want to do. You don’t have to worry about the weather.”

So what does it feel like, being there at night, watching the night sky?

Milky Way,  photo: Petr Horálek
“It’s like a miracle. It’s like being closer to the universe. The sky is very dark, because these parts of Chile is very far from the city and the light pollution is very low.

“The Milky Way is so bright that you can actually picture your own shadow and because of the darkness, the sky is much richer in stars and other objects. So it is really very easy to make a wonderful picture there. You don’t even need any special equipment, because the conditions are so good.”

Several of your pictures were chosen by NASA as Astronomy picture of the Day. How important is it for you?

“It is of course a huge honour. I can mention that some of the pictures were actually taken in the Czech Republic and they show the Czech countryside with something in the sky.

“But also, my mission is to show people that light pollution is a serious problem. And when NASA started to publish my images, people somehow started to take me more seriously.”

What are your plans into the future? IS there a place you would like to visit?

“Atacama desert is of course not the only place in the world with wonderful night sky. I was in Namibia for several times, but also in the Canary Islands, Australia, New Zealand and the Cook Island.

Namibian Geminid night,  photo: Petr Horálek
“My biggest dream is to earn enough money to make this trip again, not only to Cook Islands, but also along the South Pacific, to enjoy the night sky from these islands.

“But my next “real” plan is to visit Namibia again, because of the upcoming total lunar eclipse, which will occur on July 27. This eclipse will be very rare, because it will be the lunar eclipse in the century.

“And on the same day, there is the biggest opposition of Mars since 2003. So there will be two very unique phenomena in the sky almost in the same moment.”