Eclipse photographyUSA 2017

Is this the defining photo of the Great American Eclipse?

HDR astrophotographer Nicolas Lefaudeux explains how he got this fabulous image of the Sun’s corona during last year’s Total Solar Eclipse

Image Credit & Copyright: Nicolas Lefaudeux

They might call us eclipse-chasers, but most astronomers and astrophotographers are after just one thing during a total solar eclipse; the Sun’s mighty corona. After many months of careful post-processing, French optical engineer and amateur astrophotographer Nicolas Lefaudeux recently published a fabulous HDR example of just that, which was deservedly selected to be NASA’s Astronomy Picture of the Day.

Here he answers some questions from
Q: Where were you on 21 August, 2017, and why did you choose your location?

A: I was in Unity, Oregon. I chose Oregon beforehand as it provided the best prospects for seeing the eclipse (lowest cloud cover) and also because the timing of totality in the morning let me expect a good seeing. The final location in Oregon was chosen according to the latest weather forecast in order to avoid both high clouds and smoke from wildfires.

Q: Briefly describe your experience, and your camera set-up.

A: The set-up is quite common, it consisted in an apochromatic refraction of 100mm diameter, with a field flattener to get sharp image over the whole field of view, and a high resolution digital camera, the Sony A7R2. In order to obtain such image quality, even if the setup is simple, everything must be perfect: focusing, tracking, no vibration, etc… which is not so straightforward.

Q: What is the ‘Druckmuller’ style, and why did you choose to use it?

A: There is no ‘Druckmuller’ style as such, but rather a method of processing with different steps. Those steps are no magic, they are the right way to do stuff in order to reveal the details of the solar corona.

And when those details are revealed, you end up with images of a “certain style” which can be called Druckmuller style as he Miloslav Druckmuller was the first to do it. Thus it is not so much about choosing a style but more about doing the things the right way to reveal solar eclipse details. Even though the steps are the same as Druckmuller’s ones, in the end, my image is quite different, because I used different filters to enhance the details and because of my own personal taste.

Q: Why did it take you so long to process?

A: I did all the processing steps from scratch, and I have gone through a lot of trials and errors. I obtained good results much earlier, but there were still artifacts in the image. Spotting what made them and finding how to correct them took a lot of time. Eventually, when I showed the image when I got results that fully satisfied me, i.e. no artifacts, all the subtle details of the solar corona revealed, while keeping the natural aspect of the eclipse.

Q: You say your last eclipse was 1999. Do you regret not going to more total solar eclipses?

A: Obviously I do! But there are a lot of things to do, a lot of travels to make, and time and money constraints impose to make choices between them!

Q: Where do you plan to be for July, 2019 & December 2020? (I will be in the Elqui Valley)

A: If I go to TSE 2019, I should be in Chile, either Elqui Valley or La Silla or elsewhere according to the last weather forecasts.