Shooting the Nighttime Skies

The structure working its way up from the bottom is IC1396, also called the Elephant’s Trunk Nebula. This nebula is located in the constellation Cepheus, and is about 2,400 light years away. Photo by John Lyon.

The astrophotography of John Lyon

As he approached retirement from his post as a chemistry professor at the University of Wisconsin-Green Bay, John Lyon decided he needed to plan how to use his free time. That led to him combining his long-standing interests in photography and astronomy to come up with astrophotography. 

Technically, astrophotographers take astronomical objects and events as their subjects. This differs from the observational astronomy used by scientists, with a goal of capturing aesthetically pleasing images rather than data. 

It’s a hobby that’s easy to start, not so easy to stop.

“Like lots of hobbies there’s a huge span of costs, from basically doing photography with an iPhone up to hundreds of thousands of dollars in equipment,” Lyon said. “I started with equipment that cost under $1,000 and got good images. It’s also a hobby that once you start there is always another piece of equipment you want to add. You progress and you want a better image, and an easier time making good images.”

He uses a 4-inch refractor and a computer-controlled mount.

“You would tell the microprocessor what object you want to scan to,” he said. “A motorized mount allows you to follow the stars as they move across the sky. For astrophotography, some kind of motorized mount to track the stars is a huge advantage.”

For the moon his approach is simpler. He shoots with an old 300mm Nikon lens, handheld at a hundredth of a second. The moon is very bright, he said, and most beginners overexpose it and their image is just a white blob. 

“If you shoot 20 to 30 images handheld you’ll get one or two,” he said. “Using a tripod you’ll probably get clear images 70-80% of the time.  But while the moon is huge and bright, details are small, and if the atmosphere isn’t clear it will blur the image.”

Good astrophotography requires certain discomforts – sleep deprivation and cold. Winter nights that have been still for days are great.

“The worst time is when you have a front coming through with a lot of different temperatures,” he said. “Mixing different densities of air causes the stars to twinkle.” 

Moist air is also something to avoid.

“If you look at the sky and see a halo around the moon, that means there is a lot of high-altitude water vapor, and you get scattering,” he said. “A really cold night is good, and if it has been cold for a while, you get low moisture in the atmosphere.”

Summer is a challenge because the nights are so short. “Spring is the time to take pictures of galaxies,” he said. “In the fall and winter there are a lot of good nebulae to image. In summer, the time is so short you get the tail end of the galaxy season and the beginning of nebulas, depending on how late you want to stay.”

Lyon does his exploration of the skies from the backyard of his house between Casco and Luxemburg where he keeps a setup that allows him to start shooting in five to 10 minutes. Skies are good so he doesn’t feel a need to travel to Newport State Park, which has protected dark skies.

“I have a lot of friends who travel to the park and do fantastic work when they get really dark skies, but I like a nice warm bed when I get done,” he said.

“I would really like to spend a lot of time on a single object and see how far I can push the quality of the image, but when I start one of those projects I usually end up falling flat because the next time I get to shoot, that object might not be in the sky. I need to collect the images in a single night because the next opportunity to shoot it again might be a month away.”

He uses equipment made specifically for astrophotography and has a camera with a cooling device on the sensor that can drop it to below the ambient temperature to cut down on thermal noise, which gives a cleaner image by reducing the atmospheric noise, light pollution and camera noise.

Specialized software, like Deep Skies Stacker freeware, lets him take a group of images and combine them for a final image he can process in Photoshop. He is processing almost all his new images in Pixinsight. 

“It has so many features it takes years to master it,” he said.

The technology is so different from 20 years ago, he said, and excellent equipment is now within reach of a larger portion of the population. 

“How you present the information, how you process it, is the art part of it,” he said. “The data is real, but how you accentuate different aspects depends on the photographer. That’s also true for the Hubble and James Webb photographs. They start as black and white and are combined to make a color picture that is pleasing to the eye.”

Seven years into retirement, after 31 years of teaching in different colleges around the country, he is pleased with his retirement planning. Astrophotography, gardening and working with his wife, Kim, in her Ladybug Gallery in Algoma keep him mentally challenged.

A room in the gallery is filled with images printed on metal that he and a few friends have made of the skies. Prices are reasonable, around $150 depending on size, and they have some collectors who have bought several prints. 

Although astrophotography hobbyists aim to create aesthetically pleasing pictures rather than advance the science, hobbyists have discovered celestial bodies such as nebulae, comets or a meteor hitting Jupiter.

Scientists are exploring with tools like the James Webb Space telescope, which cost over $10 billion and is now more than one million miles from earth. It has captured views of a dying star, the formation of a new star, a cluster of five galaxies, and the deepest infrared image of the universe to ever exist.

“What we are learning from space, we are trying to describe an elephant by touching its toenails,” Lyon said. “Our understanding is naive.” 

Scientists have discovered galaxies that are far older than they thought the entire universe was, he added.

“In another century our understanding will be very different,” Lyon continued, speaking as a scientist. “Our discoveries are so, so small, giving us an incremental increase in our knowledge.”