Talented astrophotographer Andrew McCarthy has posted a wonderous 145-megapixel image of the sun he captured with a specially modified telescope.
The incredible detail of our nearest star is a complex image that essentially boils down to capturing two of the Sun’s three atmospheres.
The first is the Corona, the outermost part of the Sun’s atmosphere, which McCarthy tells PetaPixel he captured back in 2017.
There's the corona shot by itself. Now that I know more about photography, I'm looking forward to the next eclipse when I can get a much more detailed shot. pic.twitter.com/YZ8ObdeIIU
— Andrew McCarthy (@AJamesMcCarthy) August 16, 2022
“The Corona shot was captured using a Canon Digital Rebel and a 300mm Tamron telephoto lens,” he explains.
“It was captured with automatic settings, as it was before I learned anything about photography. I believe the exposure was about one second.
“For the next eclipse, my approach will be quite different.”
The second element of the photo, the chromosphere, was captured last Tuesday. But this capture required a far more advanced kit than a Canon Rebel.
“The chromosphere was captured using a modified 5-inch refractor telescope,” McCarthy says.
“It was modified using multiple filters, including an electronic-tuned hydrogen alpha filter called a ‘daystar quark’ which allows me to see the narrow bandpass of light that makes the atmospheric details of the chromosphere visible.”
The chromosphere image is a mosaic of some 45 tiles, with each tile a stack of 2,000 photos. His telescope has a focal length of 4,000mm.
“This was necessary to incorporate ‘lucky imaging’ to get a sharper image. Each individual shot was captured at six milliseconds and 100 gain through the heavily filtered telescope at f/27.”
McCarthy says that he is forever “tinkering” with his telescope, using custom and modified parts, to get greatly detailed images.
It is nearly impossible to shoot the Corona and the Chromosphere together because of the extreme differences in brightness which is why McCarthy composited the images together so the two solar atmospheres can be seen together.
Similar to photo stacking, lucky imaging is more commonly used for imaging the Moon, Sun, and Planets.
“What you have to do is take thousands of pictures of something over the course of a few minutes, and then stack them with software and it makes the image way clearer,” McCarthy writes on his website.
“This is due to the atmosphere, when you’re that zoomed in through miles of atmosphere, it ripples with the currents, destroying your image,” he explains.
“The software analyzes the images looking for the ones where this effect is the least pronounced, then stacks and sharpens them, revealing an image that is not just good, but better than what your eyes can even see.”
This is not the first time McCarthy’s celestial images have lit up the internet. He recreated NASA’s famous “Pillars of Creation” Hubble image of the Eagle Nebula with a $500 telescope.