“The best way to begin is just to put a camera on a tripod and take pictures”

“The best way to begin is just to put a camera on a tripod and take pictures”

Thierry Legault is French. He is an engineer. And he is also a renowned amateur astronomer and astrophotographer. One of Legault’s most famous photos, which shows the ISS transiting the sun, appeared in several magazines worldwide.


Thanks so much for talking to us. Please introduce yourself to our community.

I’m engineer in a large aerospace company, aged 51. Amateur astronomer since teenage.


An astrophotographer is A. an astronomer who takes photos, or B. a photographer who is an amateur astronomer?

Both may happen (I know photographers who became interested in astronomy after trying nightime shots), but generally, it’s A. People begin with astronomy (visual observation) and then many of them want to keep traces of what they see (or what they don’t see: long exposure allows to record things that no telescope in the world can show visually). Perhaps like underwater photography: you begin with diving and later you try to take pictures. To be able to take pictures of the sky, anyway you need to have a minimum knowledge of what is in the sky, when/where/how it is visible etc.


How did you come to astronomy and when did you discover astrophotography as a hobby?

When I was teenager, I read popular science magazines and one day a found a special issue about astronomy. One of the articles was about amateur astronomers, with pictures of telescopes, and I said to my parents: I would like to have a telescope! Several years later (and several changes of telescopes), I tried film photography (it was in the 70’s!) to record the planets, lunar craters etc. I became in charge of the photo lab of my local astronomy club.


You are renowned for your images, one of the most famous showing the International Space Station (ISS) transit the sun. How much planning was needed to get this shot?

The easiest part is the calculation, performed with a website called Calsky.com, as soon as you know how to use it (it’s full of numbers everywhere!). Well, you know where and when the transit is visible. You have to plan your trip to the center of the visibility path (approx. one mile wide only, sometimes less). If you are very lucky, it’s in your backyard, but generally you have to put the equipment in the car … or in a plane. My farthest transits were taken from Australia, Sultanate of Oman and Florida. But the most difficult part is the weather: a small cloud just in front of the Sun at transit time and it’s lost!




What basics (equipment, knowledge) does a person who wants to start with astrophotography need?

The best way to begin is just to put a camera on a tripod and take pictures of constellations or the Milky Way. Preferably with a DSLR, allowing bulb exposures and good image quality. Most compact cameras are very limited.


How much photo editing is involved?

It can be just a little bit for images taken with a camera on a tripod (actually not more than with ordinary pictures). But much more for specialized shooting like the planets with video cameras, where specialized astronomical software take care of complex processing including morphing and automatic selection of the best frames in the video (the ones where the image is not blurred by atmospheric turbulence). Photoshop is a toy for us!


I am curious, do you still have an overview over how much money you’ve invested in your hobby so far?

I prefer not calculating the total! But after all, some invest a lot for sailing, for example. Or in luxury cars. No equipment is totally versatile, therefore when you want to take pictures of everything happening in the sky, as I do, you need different types of telescopes and cameras. But it’s not mandatory and many people only have one telescope and one camera.


Is it easier for people these days to begin with astrophotography because of cheaper and better soft- and hardware?

It’s much much easier now with digital cameras. Actually it’s another world, and digital sensors were a true revolution for astronomy, almost comparable to the invention of spectroscopy or even the telescope. Digital cameras are much more sensitive and the result is visible immediately on the screen, so that we can identify the problems immediately (bad focus, bad tracking, bad exposure time, bad settings etc.) and improve very quickly.


You are located in France. Is it a good place for taking a shot? And is there any place you wish you could go to at some time?

Not really. Northern France is latitude 50° North and clear nights are not frequent (sometimes no clear night at all during one month in Winter, and a few even in Summer). It’s not California! Moving with the telescope is an advantage, and also patience and perseverance!!! But astronomy is a hobby and my job is more important. I go where I need, depending on my availability (I travel a lot for business but generally I don’t have time to practice astronomy during those trips). For example, next month I will go to Norway for polar auroras (“northern lights”).


You and your images are world-renowned, have received several prizes and there is also an asteroid named “Legault”. Any goals in life left?

Just continuinng to enjoy astronomy, and share my experience with other’s. It’s a hobby!


Book: “Astrophotography” Thierry Legault

More info on astrophoto.fr



Fotos: ISS and ATV-5 European Cargo (Sept. 2014) und Thierry Legault via http://legault.perso.sfr.fr/ISS_ATV5.html