An Ottawa astrophotographer, fascinated with space for years, has gained recognition from NASA scientists for a dramatic picture of the aftermath of two colliding galaxies.
In the picture, it looks like a pale but fiery strip of orange curls around a blue and purple swirl of stars. The two shapes meet in a flash in the middle, creating the impression, like the Astronomy Day Image The description goes that "this galaxy is jumping through a giant ring of stars".
Rudy Kohl, the Ottawa man behind image processing, said "there is a gravitational force that was created between them, sort of separating it," although he was quick to add that he was not an astronomer.
In a telephone interview with CTVNews.ca, Kohl said he was thrilled to have his picture chosen by NASA's astronomical image of the day – his second image since he started sending to NASA.
"It's really extraordinary to get one of these," he said. "Hundreds of images are sent to NASA every day for this."
The Astronomy Picture of the Day has been on display since 1995, and each photo comes with an explanation of the image, provided by a professional astronomer.
Although it appears that two galaxies are fighting before our eyes, the blue and orange arms of the image are part of the same galaxy: NGC 7714.
According to the description, the image shows how NGC 7714 was “stretched and distorted by a recent collision” with NGC 7715, a smaller neighboring galaxy, which is to the left of the image frame.
Scientists believe the NGC 7715 "charged directly for the NGC 7714".
The golden ring of light in the image is made up of millions of older stars thought to be similar to our sun, the description says, while the bright center of NGC 7714 is the nexus of a new star formation for the galaxy.
You would never guess by looking at the vibrant colors of the image, but this image began as a series of black and white photos taken by NASA's Hubble telescope.
It took hours of work to process the image, but Kohl, 69, was happy to do so.
Kohl is part of an online community of astrophotographers who create stunning color photographs of space. While some have their own telescopes and sky-shooting equipment, others rely on free files such as the legacy Hubble file, to find the source images to create your masterpieces.
If the source images are in black and white, does that mean that those who process the images are choosing colors randomly?
Not according to Kohl. The color streaks are in the filters Hubble uses, he said.
“What they do is put a color filter in front of the camera in black and white. In this case, there are three colors: red, green and blue. It is called RGB image. It's the same image as on our computer monitors and our televisions, ”he explained.
“Each pixel is made up of a percentage of red, percentage of green and percentage of blue.
“Then the Hubble camera puts a red filter in front, which means it blocks everything except red, and the red wavelength hits the camera and you get an image.
Although the image still comes out in black and white, it is effectively an image of what the galaxy would look like if it were just red light.
The process is repeated with blue and green filters, Kohl said, producing countless images that – while technically grayscale images – contain a huge amount of information about where different wavelengths of light and therefore different colors are concentrated in the image. .
Astrophotographers capture these different grayscale images and fill them with the color corresponding to the filter with which they were taken; therefore, they end up with numerous layers of red, blue and green from the same deep space object. When they align the different images, it is when the actual image of a galaxy, star or nebula begins to form.
It takes a lot of processing and refining of the different layers to filter out noise in the images and produce a final photo that looks as sharp as NGC 7714's Kohl photo. Kohl said it could take 12 to 16 hours to finish an image.
He used to have his own telescopes and equipment to imagine the skies, but when a chronic illness advanced on him, he said he needed to sell his equipment.
"It broke my heart to do that," he said.
Working with public archives of spatial images has allowed her to maintain her passion.
A love of science is something that has informed most of his life. Kohl majored in molecular genetics at Carleton University and met his wife while studying science. He has only started posting astrophotography photos in recent years, but is not slowing down now.
"I'll do it for the rest of my life now," he said. "I'm as impressed as when I think of the vastness of space."
NGC 7714 is about 100 million light years away from Earth, making it a relatively close cosmic neighbor.
According to APOD, NGC 7714 and NGC 7715 began interacting about 150 million years ago, and are expected to continue for several hundred million years, possibly resulting in the combination of the two into a single galaxy.