Astrophotographer’s statement “I threw Sirius out of focus and took this series of short exposures (1/25-second) with a 150mm telephoto lens on a Canon 5D Mark IV earlier this month [January, 2021]. The images are raw right out of the camera and not altered in any way. They show not only the star’s remarkable color changes but also its changing brightness as eddies of air of different temperature and pressure pass by.
At nightfall on April 6, on a visit to the countryside, I was drawn outdoors by an exceptionally clear, deep dark and starry sky. In every direction the stars were twinkling. From the southwest, flashing Sirius, the brightest of all stars seen from Earth, to pulsing Arcturus in the east, something out of the ordinary was happening. Sirius took hold of me, inspired me to concentrate my gaze to discern its white light fracturing into prismacolors. The star flickered, throwing off fragments of green, blue and red dazzle. It was like gazing at sunlight on snow or on jiggling dewdrops or a finely faceted diamond in daylight.
Above Sirius, it seemed a breeze in the atmosphere brushed by Procyon, Betelgeuse, Castor, Pollux and Capella, their twinkling reminiscent of wind lifting and twirling leaves in the crowns of trees. I walked north to a clearing to see the sky to the northeast and east. Everywhere, stars twinkled zestfully.
In my search for words to describe the science of twinkling stars, the astronomy columnist AstroBob came to my attention. I had already penned the headline “wildly twinkling stars” when I read Bob King’s wonderful description of Sirius: “Flashing wildly on turbulent nights, the brightest nighttime star is a mesmerizing sight.” I not only found the atmospheric context – turbulence – articulated in King’s writing, I found AstroBob the image-maker. His photograph, at the head of this article, is a rare record of a twinkling star. To my eyes, it is an artwork that captures the experience of seeing a twinkling star in time and space—a star that is most often visible as a single point of bluish-white light. King’s caption succinctly explains the science.