A ‘stellar’ hobby

Nighttime sky the focus of local photography efforts

This is a photograph of the Cygnus region of the sky taken by Todd Stephens of Marquette. Stephens also is a member of the Marquette Astronomical Society. (Photo courtesy of Todd Stephens)

MARQUETTE — As many people who have tried to take a photo of the nighttime sky can attest, “astrophotography” can be challenging.

A few local people, thought, have achieved “stellar” results.

One is Todd Stephens of Marquette, a member of the Marquette Astronomical Society.

“For amateur astronomers, long-exposure photography of the nighttime sky can show details that the eye cannot see when looking through binoculars or a telescope,” Stephens said in an email. “Digital cameras with modern sensors can show subtle colors, various wavelengths of light and dim details that cannot be seen, or are extremely difficult to see.”

The summer Milky Way, being one of the boldest objects in the nighttime sky from an area not affected by too much light pollution, is still mostly seen in grayscale, he said.

“Long-exposure photography, however, can reveal a multitude of red, blue and yellow stars, regions of magenta and blue nebulas, and large swaths of dark lanes from dust blocking the starlight from reaching our eyes,” Stephens said.

He said his interest in astrophotography began by wanting to see more than what’s visible through the eyepiece of a scope.

“Not to replace it, but to see more of what’s there that the human eye can’t see,” Stephens said.

Taking nocturnal sky photos can be tricky.

The challenge of long-exposure nighttime photography is being able to keep the camera shutter open long enough to collect enough photons to produce a pleasing image, he noted, but not so long that the motion of the stars across the sky produces streaks that blur the details of the image.

Preventing star trails requires the use of an equatorial tracking mount, which rotates the camera to follow the motion of the stars, Stephens said. These types of mounts, for photographers in the Northern Hemisphere, are aligned with the north celestial pole near Polaris and greatly extend the exposure time before star trails are apparent.

Stephens acknowledged another issue with taking pictures of the nighttime sky: fighting “noise,” which comes from the electronics in the camera, the temperature of the camera sensor and from the sky itself.

“Because objects in the nighttime sky are so dim, they are often lost in this noise,” Stephens said. “To overcome this, multiple shots need to be taken of the object and aligned and ‘stacked’ through special image processing software. Stacking not only increases the amount of photons collected from an object light-years away from the camera, but also tends to average out the noise and allows these objects to be seen in a long-exposure photograph.”

However, he noted that while many objects are quite small as seen from a human’s point of view, other objects are extremely large and require a wide field of view to frame in a photograph.

Large observatory telescopes are not required for these types of images, he said, and simple camera lenses work well.

“The Milky Way in particular is too large to fit into the field of view for most camera lenses, which requires multiple images to be stitched together to create a larger mosaic of the entire region,” Stephens said.

For one of his works, he said images were taken across seven different nights with wide-angle and telephoto lenses, with total exposure time exceeding 21 hours. The wide-angle lens was used to photograph the large-scale background detail in the Milky Way around the constellation Cygnus, and the telephoto lens was used to photograph certain areas in higher resolution.

Toward the bottom left in the photo is the bright blue star Deneb, with surrounding areas of reddish nebulosity, he said. Near the center bottom is the Veil Nebula, which is the remains of a supernova. Following the dark dust lanes toward the upper right corner of the image through the arm of the Milky Way, the stars become more dense towards the galactic core, with a brightening of the yellowish band.

MAS President Scott Stobbelaar is pleased with Stephens’ involvement in the astronomy world.

“It is very satisfying to see members of MAS making the effort to obtain very detailed photographs of the night sky,” Stobbelaar said in an email. “It encourages others in the club to do the same. It shows other members what is possible. It also shows the public the type of dark skies we have around the Marquette area.”

He even tried astrophotography without a scope.

“It is difficult,” Stobbelaar noted.

Paul Nelson, who runs the Marquette-area Creator’s Hand Photography, also is an avid astrophotographer. He recently completed a photo of the Orion Nebula, M42 and NGC 1975, also known as the Running Man Nebula.

He enjoys the pastime beyond the technical skills needed to accomplish it.

“Astrophotography allows me to see the amazing works in the heavens, and to share those wonders with people who are not able to be up in the middle of the night,” Nelson said in an email. “The stillness and quiet of the midnight hours bring a peace to my soul I don’t get in the chaos of everyday life, and I see God’s hand in the stars and contemplate life.”

Christie Bleck can be reached at 906-228-2500, ext. 250.