To Capture a Comet

Photo/Corey Husic

Since 2010, the JPL mission NEOWISE has scanned the skies for asteroids and comets. On March 27, 2020, it identified a bright comet approaching the sun. Comet NEOWISE emerged from behind the sun on July 3 and, in the following weeks, dazzled the public and inspired amateur astronomers to capture photos, including the one at left, taken by Corey Husic, a graduate student in the lab of Assistant Professor of Chemistry Maxwell Robb.

Of the image, Husic says: “I’ve been interested in nature photography for some time. More recently, I’ve become fascinated by astrophotography. I’m blown away by the idea that the same camera I use to take a photograph of a butterfly right in front of me can also take pictures of distant objects in space. I was very excited about the discovery of Comet NEOWISE, since there hadn’t been a comet this bright since the mid-’90s. I traveled to darker skies in the San Gabriel Mountains and Mojave Desert to see the comet. But given NEOWISE’s connections to Caltech/JPL, I thought it would be cool to view it from campus. I knew it would be a challenge because of the light pollution here in Pasadena. Even on the darkest of nights, it can be difficult to make out more than a few stars, but I had to give it a try. Armed with binoculars and camera, I ventured out onto Beckman Lawn on the evening of July 20. With a bit of searching, using the Big Dipper as a guide, I found the comet. With the naked eye, it was just a faint smudge, although binoculars revealed a bit of the tail. I set up my camera on a tripod, focused on a bright nearby star, and took a six-second exposure, trying to balance light coming in from the faint comet with the overpowering lights in the foreground of the image. The final image is actually a stack of multiple exposures of the same scene, a trick used to combat thermal noise, which becomes a big problem on digital camera sensors on warm summer nights. The final result is the image you see!”

Data from NEOWISE are processed at IPAC, an astronomy center at Caltech.

Learn more at neowise.ipac.caltech.edu.